Method and device for determining endurance performance index of vehicle, electronic equipment and processor

Abstract

This application discloses a method, apparatus, electronic device, and processor for determining the durability performance indicators of a vehicle. The method includes: acquiring a road load spectrum of the vehicle under vibration conditions and acquiring a second load of the vehicle under hydraulic rollover conditions; determining a first load caused by the vehicle's mass inertia based on the road load spectrum; performing matching processing on the first load and the second load respectively to obtain a matching result, wherein the matching result represents the stress amplitude distribution of different units in the vehicle over time as a function of the first load and the second load, and the strain amplitude of the materials constituting the vehicle under the coupled action of the first load and the second load; determining the linear superposition result of the damage to the vehicle under vibration and hydraulic rollover conditions based on the matching result; and determining the vehicle's durability performance indicators based on the linear superposition result. This application solves the technical problem of the inability to effectively determine the durability performance indicators of a vehicle.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and more specifically, to a method, apparatus, electronic device, and processor for determining the durability performance indicators of a vehicle. Background Technology

[0002] Currently, assessments of vehicles under hydraulic rollover conditions often employ quasi-static analysis methods, evaluating only the ultimate strength during the initial ejection and retraction of the hydraulic cylinder. These methods fail to simulate the dynamic load evolution throughout the rollover process and cannot calculate the vehicle's fatigue life or cycle count. Furthermore, fatigue life analysis is often based solely on road vibration conditions, failing to couple the damage caused by hydraulic rollover with the damage under vibration conditions. This neglects the superimposed effect of these two types of loads throughout the vehicle's lifespan, leading to significant discrepancies between predicted durability performance and actual failure scenarios. Therefore, the technical problem of low accuracy in vehicle durability performance assessment persists.

[0003] There is currently no effective solution to the aforementioned technical problems. Summary of the Invention

[0004] This application provides a method, apparatus, electronic device, and processor for determining the durability performance indicators of a vehicle, so as to at least solve the technical problem of being unable to effectively determine the durability performance indicators of a vehicle.

[0005] According to one aspect of the embodiments of this application, a method for determining the durability performance index of a vehicle is provided. The method may include: acquiring a road load spectrum of the vehicle under vibration conditions and acquiring a second load of the vehicle under hydraulic rollover conditions, wherein the road load spectrum represents the load existing between the vehicle and its hydraulic rollover system; determining a first load caused by the vehicle's mass inertia based on the road load spectrum; performing matching processing on the first load and the second load respectively to obtain a matching result, wherein the matching result represents the stress amplitude distribution of different units in the vehicle over time as a function of the first load and the second load, and the strain amplitude of the materials constituting the vehicle under the coupled action of the first load and the second load; determining a linear superposition result of the damage to the vehicle under vibration conditions and hydraulic rollover conditions based on the matching result; and determining the vehicle's durability performance index based on the linear superposition result, wherein the durability performance index represents the vehicle's fatigue life and durability mileage.

[0006] Optionally, based on the matching results, the linear superposition results of vehicle damage under vibration and hydraulic rollover conditions are determined, including: determining a critical plane in the stress tensor space of different elements in the vehicle by dividing it into target angles, wherein the critical plane is used to reflect the concentration trend of damage caused by the coupling effect between the first load and the second load; based on the critical plane, the matching results are projected and / or filtered to obtain an equivalent uniaxial strain amplitude and stress amplitude sequence consistent with the direction of the critical plane; and different elements are grouped according to the material property information to obtain a metal material element group and a welded structure element group, wherein the metal material element group and the welded structure element group are respectively grouped. The material element group is used to represent multiple non-welded structural components, and the welded structure element group is used to represent the connection area formed by welding. Based on the equivalent uniaxial strain amplitude, stress amplitude sequence, and the metal material element group and welded structure element group, the number of cycles experienced by each finite element under the matching result is determined. Based on the number of cycles and the linear cumulative damage rule, the initial damage is determined, where the initial damage is used to represent the local fatigue damage value accumulated by the finite element under a single load cycle under vibration and hydraulic overturning conditions. The initial damage is coupled and calculated to obtain the linear superposition result of the damage under vibration and hydraulic overturning conditions.

[0007] Optionally, based on the linear superposition results, the vehicle's durability performance indicators are determined, including: performing a three-dimensional mapping of the linear superposition results according to spatial location to obtain a distribution cloud map of the linear superposition results, wherein the distribution cloud map is used to represent the three-dimensional distribution shape and gradient characteristics of the linear superposition results in space; based on the distribution cloud map, determining the fatigue failure critical region corresponding to the linear superposition results, wherein the fatigue failure critical region is used to represent the position where the linear superposition results are greater than or equal to the threshold of the linear superposition results under the coupling effect between the first load and the second load; based on the fatigue failure critical region, determining the fatigue life, and based on the fatigue life and the length of the test section where the vehicle is located, determining the durability performance mileage, wherein the fatigue life is used to represent the total number of cycles that the vehicle undergoes from zero damage accumulation to failure.

[0008] Optionally, the first load is matched to obtain a matching result, including: acquiring a first inertial release result file and a first time history load signal under vibration conditions, wherein the first inertial release result file is used to represent the displacement, stress, and Gaussian integral point force results calculated by inertial release when a unit load is applied to the first load under no external constraints, and the first time history load signal is used to represent the simulated load signal borne by the vehicle's cab and hydraulic tilting system; based on the first inertial release result file and the first time history load signal, the first load is matched to obtain a matching result under vibration conditions.

[0009] Optionally, the first inertia release result file under vibration conditions is obtained, including: obtaining the coordinates of key hard points in the cab, vehicle suspension system, and hydraulic tilting system, respectively, wherein the key hard point coordinates are used to represent the coordinates of joints with connections or the coordinates of response points of interest; applying unit force and unit torque loads to the key hard point coordinates to obtain multiple sets of independent load conditions; under the load conditions, controlling different units to balance external loads and inertial forces in a free state to obtain the displacement, stress, and Gaussian integral point force results of different units under unit load; and outputting the displacement, stress, and Gaussian integral point force results as the first inertia release result file.

[0010] Optionally, acquiring the first time-history load signal under vibration conditions includes: acquiring the initial signal of the vehicle under vibration conditions, wherein the initial signal represents the motion state of the vehicle running on road sections under different conditions; standardizing the initial signal to obtain a target signal; inputting the target signal into a multibody dynamics model for matching to obtain a driving signal, wherein the driving signal is obtained by the time-domain displacement function applied by the driving cylinder in the simulation platform; determining the frequency response functions of the target signal and the driving signal, wherein the frequency response function represents the linear transfer relationship between the displacement drive in the simulation platform and the target sensor response in the vehicle in the frequency domain; outputting the displacement drive in response to the frequency response function satisfying the coherence function condition and the error value of the target signal being less than the error value threshold, wherein the displacement drive represents the frequency domain excitation component corresponding to the time-domain displacement function; and inputting the displacement drive into the multibody dynamics model for simulation to obtain the first time-history load signal.

[0011] Optionally, the second load is matched to obtain a matching result, including: acquiring a second inertia release result file under hydraulic tilting conditions and a second time history load signal under hydraulic tilting conditions, wherein the second inertia release result file is used to represent the displacement, stress, and Gaussian integral point force results calculated by inertia release when a unit load is applied to the second load under no external constraint conditions, and the second time history load signal is used to represent the load sequence generated under hydraulic tilting conditions and when the vehicle's cab is in an unlocked state; based on the second inertia release result file and the second time history load signal, the second load is matched to obtain a matching result under hydraulic tilting conditions.

[0012] According to another aspect of the embodiments of this application, a device for determining the durability performance index of a vehicle is also provided. The device may include: an acquisition unit for acquiring a road load spectrum of the vehicle under vibration conditions and a second load of the vehicle under hydraulic rollover conditions, wherein the road load spectrum represents the load existing between the vehicle and its hydraulic rollover system; a first determination unit for determining a first load caused by the vehicle's mass inertia based on the road load spectrum; a matching unit for performing matching processing on the first load and the second load respectively to obtain a matching result, wherein the matching result represents the stress amplitude distribution of different units in the vehicle over time as a function of the first load and the second load, and the strain amplitude of the materials constituting the vehicle under the coupled action of the first load and the second load; a second determination unit for determining, based on the matching result, the linear superposition result of the damage to the vehicle under vibration and hydraulic rollover conditions; and a third determination unit for determining the vehicle's durability performance index based on the linear superposition result, wherein the durability performance index represents the vehicle's fatigue life and durability mileage.

[0013] According to another aspect of the embodiments of this application, a processor is also provided. The processor is used to run a program, wherein the program is executed by the processor to perform the methods described in the embodiments of this application.

[0014] According to another aspect of the embodiments of this application, an electronic device is also provided, including: a memory storing an executable program; and a processor for running the program, wherein the program executes the methods in various embodiments of this application when it runs.

[0015] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored executable program, wherein, when the executable program is running, it controls the device where the computer-readable storage medium is located to perform the methods of various embodiments of this application.

[0016] According to another aspect of the embodiments of this application, a computer program product is also provided, including a computer program that, when executed by a processor, implements the methods of various embodiments of this application.

[0017] According to another aspect of the embodiments of this application, a computer program product is also provided, including a non-volatile computer-readable storage medium storing a computer program that, when executed by a processor, implements the methods in various embodiments of this application.

[0018] According to another aspect of the embodiments of this application, a computer program is also provided, which, when executed by a processor, implements the methods of the various embodiments of this application.

[0019] According to another aspect of the embodiments of this application, a vehicle is also provided. The vehicle includes a memory and a processor. The memory stores an executable program; the processor is used to run the program, which, when running, implements the methods described in the embodiments of this application.

[0020] In this embodiment, after obtaining the road load spectrum of the vehicle under vibration conditions, the second load of the vehicle under hydraulic rollover conditions, and determining the first load caused by the vehicle's mass inertia based on the road load spectrum, the first and second loads can be matched to determine the stress amplitude distribution of different units in the vehicle over time as a function of the first and second loads, as well as the strain amplitude of the materials constituting the vehicle under the coupled action of the first and second loads. This allows for the determination of the linear superposition of damage under vibration and hydraulic rollover conditions, further determining the vehicle's durability performance indicators. This embodiment overcomes the limitations of related technologies that consider only a single operating condition and determine only a single damage, leading to errors in the determination of durability performance indicators. It thus solves the technical problem of not being able to effectively determine the vehicle's durability performance indicators, achieving the technical effect of effectively determining the vehicle's durability performance indicators. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0022] Figure 1 This is a flowchart of a method for determining the durability performance index of a vehicle according to an embodiment of this application;

[0023] Figure 2 This is a flowchart of a durability simulation method for a vehicle body and hydraulic rollover system according to an embodiment of this application;

[0024] Figure 3 This is a schematic diagram of a sensor arrangement for road load spectrum testing according to an embodiment of this application;

[0025] Figure 4 This is a flowchart of a multibody dynamics modeling method according to an embodiment of this application;

[0026] Figure 5 This is a schematic diagram of a Stuart-type virtual vibration table according to an embodiment of this application;

[0027] Figure 6 This is a flowchart of a virtual load iteration method according to an embodiment of this application;

[0028] Figure 7This is a schematic diagram of the time-domain load on the vehicle body supported by the hydraulic cylinder under a rollover condition according to an embodiment of this application;

[0029] Figure 8 This is a flowchart of a fatigue damage accumulation calculation method according to an embodiment of this application;

[0030] Figure 9 This is a schematic diagram of a device for determining the durability performance index of a vehicle according to an embodiment of this application. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0032] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, functional component, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, functional components, or devices.

[0033] According to an embodiment of this application, an embodiment of a method for determining the durability performance index of a vehicle is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0034] Figure 1 This is a flowchart of a method for determining the durability performance index of a vehicle according to an embodiment of this application, such as... Figure 1 As shown, the method may include the following steps.

[0035] Step S102: Obtain the road load spectrum of the vehicle under vibration conditions, and obtain the second load of the vehicle under hydraulic rollover conditions.

[0036] In the technical solution provided in step S102 of this application, the road load spectrum can be used to represent the load between the hydraulic rollover systems of vehicles.

[0037] In this embodiment, dynamic response signals directly related to the vehicle's hydraulic rollover system and body structure can be accurately collected during the vehicle's real-world road durability test, thereby constructing load information that can truly reflect the interaction between the vehicle body and the hydraulic rollover system under different working conditions.

[0038] Optionally, the aforementioned road load spectrum refers to a series of dynamic response signals generated during actual vehicle operation by the combined effects of road surface unevenness, vehicle speed, suspension stiffness, and vehicle mass distribution. These response signals can be acquired by sensors deployed at key connection points. For example, the response signals may include, but are not limited to: the triaxial acceleration signals of the upper and lower supports (body end) and lower supports (frame end) of the front and rear suspensions of the cab, the axial relative displacement signals of the spring dampers and the hydraulic tilting cylinder, and the triaxial acceleration signals of the upper and lower supports of the hydraulic tilting cylinder. These response signals record the time-varying inertial loads applied to the vehicle body structure by the six-degree-of-freedom vibration motion of the cab relative to the frame due to road excitation during vehicle operation, which is then transmitted to the structure through the connection interface between the suspension system and the hydraulic tilting system. This load is not actively generated by the hydraulic system, but is passively transmitted to the structure by the inertial effect of the vehicle mass under dynamic excitation; it is essentially a mass inertial response.

[0039] Optionally, the second load (i.e., the time-domain load) under the aforementioned hydraulic tilting condition refers to a series of dynamic loads generated at the connection points between the hydraulic tilting system and the vehicle body (e.g., the upper lifting lug of the hydraulic cylinder, the lower support, and the frame fixing point) during the process where maintenance personnel actively drive the cab to complete a tilting action (e.g., tilting it from the locked state to the maximum tilt angle and then lowering it back to its original position) under conditions where the vehicle is stationary and there is no road excitation. The generation of this second load depends on the displacement control of the hydraulic cylinder, the driving speed, the friction characteristics, the instantaneous impact of the locking mechanism, and the rotational inertia of the cab itself, and is unrelated to road conditions, vehicle speed, suspension response, etc.

[0040] Optionally, a typical characteristic of the second load is a drastic change in force value within a very short time. For example, during the initial ejection and final return phases of the hydraulic cylinder, significant impact loads are generated due to the disengagement / engagement of the locking mechanism. This type of load is an actively driven load that can be directly transmitted to the vehicle body structure through the hydraulic cylinder bracket, and is a direct cause of weld cracking in the hydraulic cylinder bracket and fatigue damage in the rear suspension area of ​​the cab.

[0041] In this embodiment, traditional simulations often neglect the dynamic participation of the hydraulic rollover system under vibration conditions, only using the suspension load as the vehicle body load input. However, this embodiment can simultaneously acquire dynamic loads at the hydraulic cylinder bracket, achieving complete capture of the loads from the combined effects of vibration and hydraulic rollover conditions. The resulting road load spectrum not only includes the inertial loads caused by road surface excitation but also implicitly includes the unexpected dynamic response of the hydraulic rollover system caused by vehicle body vibration.

[0042] Step S104: Based on the road load spectrum, determine the first load caused by the vehicle's mass inertia.

[0043] In the technical solution provided in step S104 of this application, a high-precision multibody dynamics model of the vehicle can be established, and the first load caused by the vehicle's mass inertia and acting on the connection points of the vehicle body and hydraulic rollover system can be derived in reverse. For example, by establishing a high-fidelity system-level multibody dynamics model, combined with the road load spectrum, and using virtual load iterative inversion technology, the first load (i.e., the time-domain inertial load) can be decoupled from the overall response in reverse.

[0044] In this embodiment, the aforementioned road load spectrum records the acceleration and displacement responses at locations such as the cab suspension upper support and the hydraulic tilt cylinder upper support, reflecting the cab's motion attitude relative to the vehicle frame. However, these responses are the result of the dynamics of the entire vehicle system, rather than loads directly acting on the vehicle body.

[0045] Optionally, to obtain the actual loads borne by the vehicle body, a hybrid rigid-flexible multibody dynamics model can be established, including the cab (rigid or flexible), suspended elastic elements (springs, shock absorbers, bushings), hydraulic tilting mechanism (hydraulic cylinders, connecting rods, brackets), frame (rigid or flexible), and a Stuart-style virtual vibration table (which can be simply referred to as a virtual vibration table). This multibody dynamics model uses the six degrees of freedom displacement / force at the frame end as unknown inputs and the measured response at key points of the cab as the target output.

[0046] Optionally, in this multibody dynamics model, a set of random drive signals generated by a combination of white and pink noise can be applied to excite the chassis end, calculate the theoretical response at each measuring point in the cab, and compare it with the measured road load spectrum in the frequency domain. A mathematical mapping between the input excitation and the output response is established using the Frequency Response Function (FRF). Then, an iterative algorithm continuously corrects the input load at the chassis end, ensuring that the simulated output and the measured signal continuously approximate each other in the time and frequency domains, until the root mean square error of the main target signal (e.g., the acceleration of the upper suspension bracket and the upper hydraulic cylinder bracket) is less than 15%, the relative damage error is controlled between 0.85 and 1.15, and the auxiliary signal error also meets the acceptable engineering range. At this point, the converged chassis end drive signal is the external excitation required by the entire vehicle system under real road surface excitation.

[0047] Optionally, the aforementioned second load is an additional dynamic force generated under hydraulic tilting conditions due to factors such as the relative movement of the hydraulic cylinder piston and cylinder body, internal oil pressure fluctuations, bushing nonlinear stiffness, and structural resonance, especially the fluctuating load at the upper and lower supports of the hydraulic cylinder that exceeds the transmission range of conventional suspension mounts. The second load is not directly excited by the road surface, but is excited by the inherent dynamic characteristics of the hydraulic tilting system coupled with vehicle body vibration. The aforementioned first load can also be called the vibration condition load, and the second load can also be called the hydraulic tilting condition load. It can be that the frame transmits the first and second loads to the cab through the suspension mounts and the hydraulic tilting system.

[0048] In this embodiment of the application, the first load caused by the mass inertia of the vehicle is determined based on the road load spectrum, providing a real, complete, and physically interpretable input for the subsequent determination of the vehicle's durability performance indicators.

[0049] Step S106: Perform matching processing on the first load and the second load respectively to obtain the matching result.

[0050] In the technical solution provided by step S106 of this application, the matching result can be used to represent the stress amplitude distribution of different units in the vehicle in the time dimension as a function of the first load and the second load, as well as the strain amplitude of the material constituting the vehicle under the coupling action of the first load and the second load.

[0051] In this embodiment, the first load and the second load are matched to obtain the matching result. The first load and the second load obtained by the virtual load iterative inversion technology in the previous stage are accurately correlated with the linear response characteristics of the high-precision finite element model, so as to calculate the stress amplitude distribution and strain amplitude of each finite element in different units (e.g., structure) of the vehicle under real time history.

[0052] Optionally, matching processing can be performed on the first load (e.g., time-domain inertial load) and the second load (e.g., time-domain load) to obtain the full-field time-domain stress and strain amplitude results of the vehicle. The full-field time-domain stress represents the stress amplitude distribution of different elements in the vehicle over time, varying with the time-domain inertial load and the time-domain load, while the strain amplitude results represent the strain amplitude of the materials constituting the vehicle under the action of the time-domain inertial load and the time-domain load.

[0053] Optionally, unit loads (unidirectional force or torque) can be applied to load input points of the vehicle body structure (e.g., front upper suspension bracket, rear upper suspension bracket, hydraulic tilting cylinder upper lug, etc.), and the displacement, stress, and Gaussian integral point force response of different units under unconstrained conditions can be calculated using an inertial release algorithm, forming a response database that corresponds one-to-one with the load degrees of freedom. That is, the stress / strain distribution of each unit of the entire vehicle structure under the action of a unit force at each input point. This response data can be stored in Output Phase 2 (OP2) format, containing complete spatial distribution information and time synchronization capabilities. Then, the time-domain historical signals of the first and second loads—that is, the six-degree-of-freedom force / torque sequence of each input point over time—can be loaded into this response database. Using the principle of linear superposition, the load vector at each time step is multiplied by the corresponding unit load response vector, and the stress and strain responses of different units throughout the vehicle are calculated point by point.

[0054] Optionally, the first load and the second load can be matched with their respective response matrices and then superimposed in the time domain to finally obtain the full-field time-domain stress and strain amplitude results of each element under the combined action of vibration and hydraulic overturning conditions.

[0055] Optionally, the matching process described above must strictly adhere to the load channel name, coordinate system direction, node number, and key header of the finite element results for automatic or semi-automatic matching to ensure that each unit load response corresponds to the correct physical point of application. After matching, the resulting value is not a single maximum value, but rather a sequence of stress and strain amplitudes that continuously change along the time axis for each element. The waveform of the matching result can reflect real physical processes such as load pulses, resonance peaks, and impact transients, providing a raw data foundation for subsequent rainflow counting, critical plane identification, and damage accumulation.

[0056] In the embodiments of this application, the first load and the second load are matched to obtain matching results, which provide accurate full-field time-domain stress and strain amplitude results for subsequent determination of the linear superposition results of vehicle damage under different working conditions.

[0057] Step S108: Based on the matching results, determine the linear superposition result of vehicle damage under vibration and hydraulic rollover conditions.

[0058] In the technical solution provided in step S108 of this application, after obtaining the matching results, that is, after obtaining the full-field time-domain stress and strain amplitude results of each element under the combined action of vibration and hydraulic rollover conditions, the damage calculated independently under vibration and hydraulic rollover conditions can be determined. Then, based on the linear damage accumulation criterion, a substitutional superposition can be performed at the element level to obtain the linear superposition result of vehicle damage under different conditions, that is, total damage coupling.

[0059] In this embodiment, the vibration condition and the hydraulic rollover condition are two load processes with independent physical mechanisms, separable application times, and linearly superimposed material responses. The vibration condition is a high-frequency, multi-directional, continuous load caused by road surface excitation during vehicle operation; the road load spectrum corresponds to tens or even hundreds of thousands of kilometers of driving cycles. The hydraulic rollover condition is a low-frequency, high-amplitude, impact load caused by the repeated rollover of the cab during vehicle maintenance (e.g., approximately 5–10 rollovers per 1000 kilometers). Although their application frequencies, load patterns, and cycle counts differ significantly, they together constitute the two major fatigue sources during the vehicle's service life.

[0060] Optionally, for each finite element in different elements, the unit cyclic damage value under vibration conditions and the unit cyclic damage value under hydraulic overturning conditions can be calculated. By linearly superimposing the two types of damage, the target damage can be obtained, that is, the result of linear superposition of damage.

[0061] In this embodiment, by accurately separating the two types of loads (corresponding to the first load and the second load), independently modeling, independently calculating, and accurately superimposing them, the coupled assessment of damage under vibration conditions and hydraulic overturning conditions is realized.

[0062] Step S110: Based on the linear superposition results, determine the vehicle's durability performance indicators.

[0063] In the technical solution provided by step S110 of this application, the durability performance index can be used to represent the fatigue life and durability performance mileage of a vehicle.

[0064] In this embodiment, the vehicle's durability performance index can be derived by combining the linear superposition results with the length of the test section where the vehicle is located (e.g., the mileage information of the measured road load).

[0065] Optionally, the damage value (D_unit) of each finite element unit in the vehicle body and hydraulic tilting system under a unit cycle is accurately calculated, and the target damage D_total is calculated based on the number of cycles (N_vib and N_flip) for the two types of working conditions. When D_total ≥ 1.0, it means that the unit has reached the critical point of fatigue failure under the current load history. At this point, the determination of the durability performance index is not simply a matter of reporting whether the limit is exceeded, but rather a further physical mapping is established between the threshold of the linear superposition result (e.g., the target damage threshold) and the actual driving and operating behavior to deduce the longest road mileage that the vehicle can safely travel under the current load spectrum intensity.

[0066] Optionally, the determination of vehicle durability performance indicators can be based on engineering inversion and calibration. Specifically, the road load spectrum is collected on a specific test section at a fixed vehicle speed (e.g., 60 km / h), and the mileage corresponding to that cycle is accurately recorded using a Global Positioning System (GPS) or wheel speed signals. Therefore, each load cycle has a clearly defined mileage. For example, a complete "cobble road + washboard road" test cycle can correspond to 5 kilometers of road mileage. After obtaining the target damage D_total for each unit, when the D_total of a certain unit reaches 1.0, the fatigue life and durability performance mileage at that location can be obtained by inversely calculating how many equivalent test cycles the damage was accumulated from, and then multiplying it by the mileage corresponding to each cycle.

[0067] For example, if a bracket reaches a damage level of 1.0 after 1000 test cycles, and each cycle represents 5 kilometers, then the predicted fatigue life is 5000 kilometers. It is possible to iterate through all units in the vehicle and output the minimum lifespan mileage as an indicator of the vehicle's durability performance.

[0068] In the embodiments of this application, the above steps achieve design-prediction, which allows for accurate prediction of failure locations and durability performance indicators before the prototype of the vehicle is manufactured.

[0069] In steps S102 to S110 of this application, after obtaining the road load spectrum of the vehicle under vibration conditions, the second load of the vehicle under hydraulic rollover conditions, and determining the first load caused by the vehicle's mass inertia based on the road load spectrum, the first load and the second load can be matched to determine the stress amplitude distribution of different units in the vehicle over time as a function of the first and second loads, and the strain amplitude of the materials constituting the vehicle under the coupled action of the first and second loads. This allows for the determination of the linear superposition of damage under vibration and hydraulic rollover conditions, further determining the vehicle's durability performance indicators. This application overcomes the limitations of related technologies that consider only a single operating condition and determine only a single damage, leading to errors in the determination of durability performance indicators. It thus solves the technical problem of not being able to effectively determine the vehicle's durability performance indicators, achieving the technical effect of effectively determining the vehicle's durability performance indicators.

[0070] The method described in this embodiment will be further described below.

[0071] As an optional embodiment, step S108, based on the matching results, determines the linear superposition result of vehicle damage under vibration and hydraulic rollover conditions, including: determining a critical plane in the stress tensor space of different units in the vehicle with target equally divided angles, wherein the critical plane is used to reflect the concentration trend of damage caused by the coupling effect between the first load and the second load; based on the critical plane, performing projection processing and / or filtering processing on the matching results to obtain an equivalent uniaxial strain amplitude and stress amplitude sequence consistent with the direction of the critical plane; and grouping different units according to the material property information to obtain metal material unit groups and welded structures. The system comprises several element groups, including a metallic element group representing multiple non-welded structural components and a welded structure element group representing the connection area formed by welding. Based on the equivalent uniaxial strain amplitude, stress amplitude sequence, and the metallic and welded structure element groups, the number of cycles each finite element experiences under the matching results is determined. Based on the number of cycles and the linear cumulative damage rule, the initial damage is determined, where the initial damage represents the local fatigue damage value accumulated by the finite element under a single load cycle under vibration and hydraulic overturning conditions. Coupled calculations are performed on the initial damage to obtain the linear superposition results of the damage under vibration and hydraulic overturning conditions.

[0072] In this embodiment, the linear superposition of vehicle damage under different working conditions is determined based on the matching results. This constructs a physical-mathematical transformation chain from the full-field time-domain stress-strain response to the accumulation of local fatigue damage. This allows for the identification of microscopic directions where fatigue cracks are likely to initiate, the quantification of the nonlinear response of materials under complex loads, and the grouping of damage by structural type to achieve differentiated damage modeling. Ultimately, this completes the high-precision coupled calculation of damage under vibration and hydraulic overturning conditions.

[0073] Optionally, if it is necessary to determine the linear superposition of vehicle damage under different operating conditions based on the matching results, the critical plane can be determined in the stress tensor space of different elements in the vehicle by dividing it into target equal angles (e.g., 18 equal angles). That is, critical plane analysis is performed on the three-dimensional stress tensor borne by each finite element in the matching results. Since fatigue cracks do not initiate in arbitrary directions, but rather preferentially form on a specific plane within the material due to the combined effects of maximum shear stress, maximum normal strain, or energy release rate, the dangerous plane direction can be systematically searched in the three-dimensional stress space of the element.

[0074] Optionally, the above process begins with a critical plane analysis of the three-dimensional stress tensor borne by each finite element in the matching results. A discrete search strategy with 18 equally divided angles can be used. In the element's local coordinate system, multiple inclined planes can be uniformly divided around the principal axis of the stress tensor, and the maximum strain amplitude, maximum normal stress amplitude, and their combined effects can be calculated for each plane. By combining the Smith-Watson-Topper (P-SWT) model, the critical plane that contributes most to fatigue damage is identified. This critical plane is the location where local damage concentration is most significant for the element under combined loading.

[0075] Optionally, after determining the critical plane, the matching results can be projected and / or filtered to obtain an equivalent uniaxial strain amplitude and stress amplitude sequence consistent with the direction of the critical plane. That is, the stress and strain tensors at each time step in the matching results are projected, converting the full-field time-domain stress and strain amplitude results into an equivalent uniaxial strain amplitude and stress amplitude sequence along the direction of the critical plane. This process, through tensor transformation and coordinate system rotation, can equate complex multiaxial non-proportional loads to a uniaxial tension-compression-bending composite time-domain history, allowing subsequent fatigue models to be applied to classical strain-life relationships. Simultaneously, to eliminate the interference of high-frequency noise and non-critical micro-fluctuations on damage calculation, filtering is applied to the equivalent sequence. A smoothing algorithm based on rainflow counting or bandpass filtering can be used to retain the load amplitudes and cycle counts that truly have cumulative damage effects, ensuring the physical validity of the damage calculation.

[0076] Optionally, for accurate modeling of material response, the vehicle structure can be intelligently grouped based on the geometric characteristics and manufacturing processes of different units. One type is the metallic material unit group, which can include integral stamped or cast parts such as the cab frame, suspension brackets, and hydraulic cylinder blocks. The material can be homogeneous metal, and the damage evolution follows the strain-controlled low-cycle fatigue law. The other type is the welded structure unit group, which can include all welds and weld points. For example, weld points between the body sheet metal parts of the cab, fillet welds between the tilting cylinder hanger and the tilting hydraulic cylinder bracket, etc. The damage mechanism is dominated by microscopic defects, stress concentration, and geometric discontinuities in the weld heat-affected zone. A weld-specific stress-life (SN) curve model based on structural stress or the resultant force (Rupp force) at the weld point can be used.

[0077] Optionally, based on the equivalent uniaxial strain amplitude, stress amplitude sequence, metallic material unit group, and welded structure unit group described above, rainflow counting can be performed on each unit to count the number of stress or strain cycles occurring under different combinations of amplitude and mean values ​​throughout the complete load history. Since vibration conditions may involve hundreds of thousands of cycles, while hydraulic overturning conditions only involve hundreds, the cycle distribution differs significantly, but the system can still record the cycle count for each separately. Subsequently, for each type of unit, based on its material group, the corresponding material's cyclic stress-strain curve and strain-life curve are input. Elastic-plastic correction is performed using the Neuber formula, and then the mean stress is corrected using the P-SWT method (welded structures do not require correction due to stress concentration). Finally, the accumulated local fatigue damage value of the unit in a single load cycle, i.e., the initial damage, is calculated. This initial damage is not a fixed constant but a physical quantity that dynamically changes with stress amplitude, strain amplitude, mean stress, and material properties.

[0078] Optionally, after obtaining the initial damage of each element under different working conditions, linear superposition can be performed. For example, for a group of metallic material elements, the damage from a single vibration condition is multiplied by the number of travel cycles, and the damage from a single hydraulic overturning condition is multiplied by the number of overturning cycles to obtain the target damage (e.g., total damage). The same logic applies to the superposition of welded structural elements. Since fatigue damage conforms to the Miner linear accumulation criterion in engineering practice, even with different load types, frequencies, and amplitudes, damage can be linearly superimposed as long as plastic instability has not occurred. This coupled calculation is not a simple arithmetic addition, but rather executed in parallel along the three-dimensional dimensions of "element-working condition-material," ensuring that each weld, each bolt connection point, and each sheet metal piece receives an independent and accurate damage assessment.

[0079] In this embodiment, a high-fidelity simulation of the entire chain—multiaxial load → critical plane identification → material grouping modeling → independent calculation of working conditions → linear coupling of damage—overcomes the shortcomings of related technologies, such as ignoring multiaxial effects, using a unified material model, and roughly estimating the rollover effect. By introducing critical plane analysis, the previously ignored 45° oblique crack initiation zone can be accurately captured. Through grouping modeling, weld fatigue assessment is transformed from experience-weighted to mechanism-driven. By independently calculating and superimposing the damage of two types of working conditions, the problem of vibration fatigue masking rollover damage or underestimating rollover load is solved.

[0080] As an optional embodiment, step S110, based on the linear superposition result, determines the vehicle's durability performance index, including: performing a three-dimensional mapping of the linear superposition result according to its spatial location to obtain a distribution cloud map of the linear superposition result, wherein the distribution cloud map is used to represent the three-dimensional distribution shape and gradient characteristics of the linear superposition result in space; based on the distribution cloud map, determining the fatigue failure critical region corresponding to the linear superposition result, wherein the fatigue failure critical region is used to represent the position where the linear superposition result is greater than or equal to the threshold of the linear superposition result under the coupling effect between the first load and the second load; based on the fatigue failure critical region, determining the fatigue life, and based on the fatigue life and the length of the test section where the vehicle is located, determining the durability performance mileage, wherein the fatigue life is used to represent the total number of cycles that the vehicle undergoes from zero damage accumulation to failure.

[0081] In this embodiment, the durability performance index of the vehicle is determined based on the linear superposition result. The abstract unit-level damage can be transformed into a three-dimensional physical image with spatial visibility, engineering recognition and design intervention. Based on this, the failure risk area can be accurately located, and the durability performance index of the vehicle can be quantified.

[0082] Optionally, the combined fatigue damage values ​​of each element, such as the linear superposition of damage under the coupled effects of vibration and hydraulic rollover conditions, are mapped according to their spatial location in the vehicle's three-dimensional coordinate system to generate a high-resolution distribution cloud map. This distribution cloud map is not a two-dimensional cross-sectional view, but rather uses a volume mesh or shell element as a carrier to render the continuous distribution of damage values ​​point by point in three-dimensional space. The color in the distribution cloud map can gradually change from blue (low damage) to red (high damage), visually presenting the spatial aggregation trend and gradient changes of damage in key areas such as the vehicle frame, suspension brackets, hydraulic rollover cylinder hangers, and rear support beams.

[0083] Optionally, the aforementioned distribution cloud map reveals that the damage is not uniformly distributed, but rather highly concentrated at points of abrupt structural changes. Examples include weld corners in the connection area between the upper bracket and the rear suspension of the tilting cylinder, and stress concentration areas in the hydraulic lock mounting plate. These areas are often overlooked in traditional two-dimensional analysis, but become hotspots with steep damage gradients in three-dimensional space. The aforementioned distribution cloud map not only reflects the magnitude of the damage but also illustrates the spatial propagation path and stress field coupling pattern, providing designers with intuitive diagnostic information.

[0084] Optionally, based on the aforementioned distribution cloud map, the fatigue failure critical region can be automatically or manually identified; that is, the structural location where the linear superposition result is greater than or equal to the linear superposition result threshold. This linear superposition result threshold is not arbitrarily set, but rather based on the physical nature of the material's fatigue limit and the Miner criterion. When the total damage of a unit accumulates to 1.0, it means that under the current load spectrum, the critical state of microcrack initiation and propagation has been reached, possessing the physical possibility of failure. The fatigue failure critical region can be distributed as discrete points or local stripes, and is directly related to structural geometrical abrupt changes, welding defects, and interruptions in load transfer paths.

[0085] Optionally, determining fatigue life involves inverting the damage accumulation process in the critical fatigue failure region into time or cycle count. Since damage is based on the accumulated damage rate (D_unit) of each unit per cycle, when the total damage D_total of a critical region equals 1.0, the corresponding total number of cycles N_total is the fatigue life at that location. That is, the total number of complete load cycles from zero initial damage to macroscopic failure. For example, if a weld accumulates damage to 1.0 after 1000 vibration cycles and 300 flipping cycles, the fatigue life is 1300 composite cycles, representing the maximum number of actions the structure can safely withstand in real-world use. Then, by correlating the fatigue life with the length of the test section where the vehicle is located (e.g., mileage information from measured road load spectra), the durability performance mileage can be derived.

[0086] As an optional embodiment, step S106 involves matching the first load to obtain a matching result, including: acquiring a first inertial release result file and a first time history load signal under vibration conditions, wherein the first inertial release result file represents the displacement, stress, and Gaussian integral point force results calculated through inertial release when a unit load is applied to the first load under no external constraints, and the first time history load signal represents the simulated load signal borne by the vehicle's cab and hydraulic tilting system; and matching the first load based on the first inertial release result file and the first time history load signal to obtain a matching result under vibration conditions.

[0087] In this embodiment, for the matching processing of the first load under vibration conditions, the inertial release-time domain load bidirectional mapping mechanism can be used to realize the multi-degree-of-freedom time domain force signal output from the virtual load inversion, and accurately restore it to the full-field stress and strain evolution process inside the vehicle body and hydraulic rollover system structure, thereby providing real, complete and physically interpretable input data for subsequent fatigue damage analysis.

[0088] Optionally, in practice, a high-fidelity finite element model of the interior body and hydraulic tilting system support structure can be established. Under conditions of no external constraints (i.e., free-floating), a unit-sized unidirectional force or torque (e.g., 1 N or 1 N·m) can be applied to each load input point (e.g., the upper bracket of the front suspension of the cab, the upper bracket of the rear suspension, the upper lug of the hydraulic tilting cylinder, etc.), and solved using the inertia release calculation card in the general-purpose structural finite element analysis software system (Nastran). By allowing the structure to respond freely under its own inertia, the displacement distribution, stress distribution, and internal force response at the Gaussian integration point of each element of the structure under a unit load under conditions without fixed boundaries can be accurately simulated. Since this process is linear and does not depend on boundary constraints, a structural response matrix can be obtained, which is the transfer function of the stress of all elements of the vehicle per unit load at each input point.

[0089] Optionally, the first time-history load signal can be obtained through multibody dynamics models and virtual load iteration techniques. This first time-history load signal represents the dynamic load sequence transmitted from the cab suspension system and hydraulic tilting system to the vehicle body via the suspension and tilting mechanisms under real road vibration conditions. This first time-history load signal is not a theoretical assumption, but rather a real load history reconstructed through inversion of measured road load spectra, containing complex time-domain characteristics (such as impact, resonance, and non-stationary fluctuations). It includes the coupled response of the first load caused by the vehicle's mass inertia and the second load excited by the dynamic characteristics of the hydraulic tilting system under vibration conditions.

[0090] Optionally, at each sampling moment on the time axis, the first load signal at the current moment (i.e., the six-degree-of-freedom force / torque vector of each input point) can be read and used as a weight to perform a dot product operation with the corresponding unit load response vector in the first inertial release result file. Since the first inertial release result file has completely recorded the stress / strain effect of each unit load on all units of the vehicle, this multiplication operation essentially activates the linear relationship between "load input" and "structural response" precisely at each instant. For example, if a Z-direction tensile force of 200N appears at the lifting lug of the hydraulic cylinder at a certain moment, the stress distribution field corresponding to the Z-direction unit load at that point can be automatically extracted, multiplied by 200, and superimposed on the overall stress at the current moment. Similarly, the X-direction force, Y-direction torque, etc. at the upper bracket of the front suspension are also superimposed one by one. Through point-by-point calculation, the complete time-domain stress and strain history experienced by each finite element element of the vehicle body during the entire vibration cycle is finally reconstructed.

[0091] In the embodiments of this application, the above steps realize a closed-loop simulation of real dynamic load-free structural response-full field stress reconstruction, so that the fatigue analysis of the vehicle body and hydraulic rollover system no longer depends on simplified equivalent loads or empirical coefficients, but is based on an engineering foundation with clear physical mechanisms, rigorous mathematical relationships and verifiable results.

[0092] As an optional embodiment, obtaining the first inertia release result file under vibration conditions includes: obtaining the coordinates of key hard points in the cab, vehicle suspension system, and hydraulic tilting system, respectively, wherein the key hard point coordinates are used to represent the coordinates of joints with connections or the coordinates of response points of interest; applying unit force and unit torque loads to the key hard point coordinates to obtain multiple sets of independent load conditions; controlling different units to balance external loads and inertial forces in a free state under load conditions to obtain the displacement, stress, and Gaussian integral point force results of different units under unit load; and outputting the displacement, stress, and Gaussian integral point force results as the first inertia release result file.

[0093] In this embodiment, obtaining the first inertial release result file under vibration conditions is a crucial preliminary step in constructing a high-precision virtual load matching system. Essentially, it lays the physical foundation for subsequent full-field stress-strain inversion of real time-domain loads by establishing a unit load response database for the structure. This process is not a simple finite element loading calculation, but rather a systematic simulation of the mechanical response characteristics of the structure under unconstrained conditions, achieving accurate modeling of the inertial force transmission path in a complex multibody system.

[0094] Optionally, starting from the physical structure, the coordinates of key hard points in the cab, suspension system, and hydraulic tilting system can be obtained. These key hard point coordinates are not arbitrarily selected nodes, but rather characteristic locations with clear mechanical functions and connection relationships. For example, the center of the connecting pin hole between the upper front suspension bracket of the cab and the vehicle body, the bolt mounting point between the upper rear suspension bracket and the cab frame, the center of the ball joint connecting the upper lifting lug of the tilting hydraulic cylinder and the cab, and the fixing hinge point between the lower hydraulic cylinder bracket and the frame, etc., are only examples and no specific limitations are made here.

[0095] Optionally, these points serve as both the physical interface for load input and the key channels for force transmission through the rigid-flexible coupling of the structure. By accurately acquiring the three-dimensional spatial coordinates of these points, the consistency between the subsequent load application location and the actual assembly state is ensured, avoiding response distortion caused by coordinate offset.

[0096] Optionally, after obtaining the coordinates of the key hard points, a unit force or unit torque can be applied to each degree of freedom (the three translational directions X, Y, and Z, and the rotational directions about the three axes) of each hard point to generate multiple sets of independent load cases. For example, if a connection point has six degrees of freedom, then a +1N X-direction force, a +1N Y-direction force, a +1N Z-direction force, a +1N·m torque about the X-axis, etc., need to be applied, for a total of six independent load cases. For the vehicle body structure, these load cases simulate how static equilibrium is achieved through elastic deformation and redistribution of internal forces when the structure resists a unit external force solely through its own inertia without external constraints.

[0097] Optionally, the inertial release algorithm can be used to solve each load case. Inertial release is a special finite element analysis technique that allows the structure to automatically balance the applied external loads in a free state without external support through the inertial forces generated by its own mass distribution. In solvers such as Nastran, the acceleration of the center of mass of the entire structure is automatically calculated, allowing the overall rigid body motion and local elastic deformation to coexist, without forced constraints or rigid body drift. Under these conditions, the stress felt by each element under a unit load is not due to the constraint reaction force caused by fixed boundaries, but rather is purely due to the internal elastic response of the structure induced by the load, truly reflecting the intrinsic transmission characteristics of the load path under unconstrained and unconstrained reaction force disturbances.

[0098] Optionally, the above calculations can output three key responses for each element under a unit load: displacement, stress, and Gaussian integral point force results. Displacement characterizes the deformation of the structure under a unit load, reflecting the stiffness distribution. Stress reveals stress concentration areas within the material and is a direct input for fatigue analysis. Gaussian integral point force results, in the form of stress integration results within the element, provide more accurate information on local load flow, especially crucial for high-gradient regions such as welds and thin-plate joints. The displacement, stress, and Gaussian integral point force results can be output in OP2 format as a first inertia release result file, forming the structure's response matrix. This results in a large dataset containing all load conditions and element responses, where each column represents a unit load and each row represents a specific type of response for an element.

[0099] In this embodiment, the aforementioned first inertial release result file serves as the physical key to the vibration load matching process. Since the first inertial release result file does not depend on the measured load but is determined solely by structural geometry, material properties, and mass distribution, it possesses high versatility and reusability. In subsequent steps, when the actual load spectrum (from virtual load inversion) is input, simply performing a dot product between the time-domain load vector and the response matrix allows for rapid and accurate reconstruction of the full-field stress-strain time-domain history of each unit in the vehicle under real road excitation, without requiring tens of thousands of finite element calculations.

[0100] As an optional embodiment, acquiring the first time-history load signal under vibration conditions includes: acquiring an initial signal of the vehicle under vibration conditions, wherein the initial signal represents the motion state of the vehicle running on a road segment under different conditions; standardizing the initial signal to obtain a target signal; inputting the target signal into a multibody dynamics model for matching to obtain a driving signal, wherein the driving signal is obtained by the time-domain displacement function applied by the driving cylinder in the simulation platform; determining the frequency response functions of both the target signal and the driving signal, wherein the frequency response function represents the linear transfer relationship between the displacement drive in the simulation platform and the target sensor response in the vehicle in the frequency domain; outputting the displacement drive in response to the frequency response function satisfying the coherence function condition and the error value of the target signal being less than the error value threshold, wherein the displacement drive represents the frequency domain excitation component corresponding to the time-domain displacement function; and inputting the displacement drive into the multibody dynamics model for simulation to obtain the first time-history load signal.

[0101] In this embodiment, obtaining the first time history load signal under vibration conditions is the core step in inverting virtual loads based on actual measurements. Essentially, it involves reconstructing the dynamic load sequence of the vehicle frame transmitted to the vehicle body through the suspension and hydraulic tilting system under real complex road conditions by using a high-fidelity multibody dynamics model and closed-loop iteration of actual road signals. This provides a physically realistic, spatially complete, and frequency-domain controllable input basis for subsequent fatigue simulation.

[0102] Optionally, the initial signals mentioned above can come from physical quantities such as triaxial acceleration and relative displacement, which are located on the upper and lower supports of the cab suspension, the upper and lower supports of the hydraulic tilting cylinder, and the axial displacement sensor. Essentially, these are the complex motion responses generated by the structure during vehicle operation on typical road sections (e.g., cobblestone roads, washboard roads, potholes), due to the combined effects of road surface excitation, mass inertia, system nonlinearity, and hydraulic dynamic characteristics. These initial signals contain a large amount of noise, drift, non-physical glitches, and channel distortion caused by sensor installation deviations or sampling asynchrony. Therefore, they can be standardized to form the target signal.

[0103] Optionally, the above standardization process may include verifying vehicle speed consistency based on GPS and wheel speed signals to ensure test data meets specifications. Signal glitches can be eliminated through threshold detection and interpolation. Baseline offset caused by temperature drift can be corrected using high-pass filtering or detrending algorithms. Amplitude and phase consistency can be verified for the left and right symmetrical channels to ensure physical logic is sound. After truncating the complete cycle, the beginning and end of the signal can be processed using a smoothing window function to make the start and end amplitudes approach zero, avoiding spectral leakage. The final output target signal is a high-quality multi-channel load spectrum with complete physical meaning, time-domain synchronization, and no systematic errors, representing the real motion response of the vehicle's suspension and hydraulic rollover system under real-world conditions.

[0104] Optionally, the target signal is input into a pre-established multibody dynamics model of the cab-suspension-hydraulic tilting system. This multibody dynamics model includes key components such as the cab (rigid or flexible), elastic suspension elements, hydraulic tilting cylinders and supports, and a virtual vibration table. Linearized modal calibration ensures that the sixth-order rigid body modes are consistent with actual measurements, providing high dynamic fidelity. In the multibody dynamics model, no load is directly applied to the chassis end. Instead, a controllable time-domain displacement function is applied as excitation through six drive cylinders on a simulation platform (e.g., a Stuart-type virtual vibration table) to simulate the six-degree-of-freedom motion of the chassis relative to the ground. By adjusting the displacement input of these six drive cylinders, the response of key sensor positions, such as the upper suspension support and the upper hydraulic tilting cylinder support, output by the multibody dynamics model approximates the target signal as closely as possible.

[0105] Optionally, to achieve the above objectives, a virtual load iteration technique can be employed. Specifically, a set of initial driving signals, a mixture of white and pink noise, can be generated to excite the multibody dynamics model and obtain the predicted response. Subsequently, the frequency response function (FRF) of the predicted response and the target signal in the frequency domain is calculated. The FRF is essentially a linear transfer matrix from the driven displacement to the sensor response, describing the dynamic amplification characteristics of the system at different frequencies. To ensure the reliability of the FRF, its coherence function can be verified; that is, it should be greater than 0.5 in the 0.5–1 Hz range and greater than 0.85 in the 1–40 Hz range to eliminate the influence of nonlinear interference and model mismatch. If these requirements are not met, the noise parameters, boundary frequencies, or pink exponent need to be adjusted, and the excitation regenerated until a highly coherent and stable FRF is obtained.

[0106] Optionally, after obtaining the highly coherent FRF, an iterative closed-loop can be initiated. Using the inverse function of the target signal and the FRF, a new driving correction is calculated, the displacement input of the virtual vibration table is updated, and the simulation is run again to output a new response. Through continuous iteration, the root mean square error (RMS) of the response of the main target channel (upper suspension bracket, upper tilt cylinder bracket) and the auxiliary channel (lower bracket, displacement sensor) with the target signal, as well as the relative damage of the signal (equivalent cumulative value based on fatigue damage), are compared. The iteration converges when the error value of the main target signal is less than the error threshold (e.g., 15%), the relative damage is between 0.85 and 1.15, and the error value of the auxiliary target is less than the error threshold (e.g., 25%), and the relative damage is between 0.5 and 2. At this point, the final displacement drive is output, i.e., a set of precise six-degree-of-freedom time-domain displacement functions. This time-domain displacement function is no longer a theoretical assumption, but a frame excitation source derived from measured data that can realistically reproduce the vehicle's motion posture under road loads.

[0107] Optionally, the displacement drive described above can be re-input into the multibody dynamics model for a complete time-domain simulation, which will output the first-time history load signal. This is the complete six-degree-of-freedom time-domain load sequence experienced by key connection points such as the front and rear suspension upper supports of the cab and the upper support of the hydraulic tilting cylinder under real road vibration conditions. This first-time history load signal includes not only vertical, longitudinal, and lateral forces, but also moments about each axis, comprehensively reflecting the composite dynamic load experienced by the vehicle body under the combined action of road vibration and hydraulic system inertial fluctuations.

[0108] As an optional embodiment, step S106 involves performing matching processing on the second load to obtain a matching result, including: acquiring a second inertial release result file under hydraulic tilting conditions and a second time history load signal under hydraulic tilting conditions. The second inertial release result file represents the displacement, stress, and Gaussian integral point force results calculated through inertial release when a unit load is applied to the second load under no external constraints. The second time history load signal represents the load sequence generated under hydraulic tilting conditions when the vehicle's cab is unlocked. Based on the second inertial release result file and the second time history load signal, the second load is matched to obtain a matching result under hydraulic tilting conditions.

[0109] In this embodiment, the second load is matched for the hydraulic rollover condition to obtain the matching result under the hydraulic rollover condition. This can be achieved by establishing a structural response database independent of the vibration condition under the physical reality of a fully unlocked cab without any constraints. The matching result is then precisely coupled with the real time-domain load generated during the hydraulic rollover dynamic process to obtain the full-field stress-strain response of the vehicle body and hydraulic cylinder bracket throughout the entire rollover process. This process is not a simple reuse of the vibration condition, but rather a construction of an independent and high-fidelity simulation system specifically for the unique floating-impact-asymmetric mechanical behavior of hydraulic rollover.

[0110] Optionally, in the hydraulic tilting condition, the cab is fully unlocked, meaning there is no rigid connection between the cab and the rear suspension hydraulic lock; instantaneous constraint is maintained only by contact force. The tilting hydraulic cylinder, as the sole power source, can achieve a complete movement from closing to tilting 90° and then falling back down via displacement drive. At this time, the vehicle body structure no longer bears the vibration response dominated by inertial loads from the suspension system, but rather bears low-frequency, high-amplitude, non-periodic loads caused by the violent extension and contraction of the hydraulic cylinder, the displacement of the cab's center of gravity, and the instantaneous impact of the lock body. Therefore, if the frame fixation or suspension constraint boundary conditions under vibration conditions are still used, it will lead to incorrect load transmission paths and severely distorted stress distribution. Therefore, a second inertial release result file under the hydraulic tilting condition can be obtained, i.e., a hydraulic tilting condition response database.

[0111] Optionally, if a second inertia release result file is required under the hydraulic tilting condition, the key load input points under the hydraulic tilting condition can be identified first, such as the connection point between the cab and the front suspension, the connection point between the cab and the upper hanger of the hydraulic tilting cylinder, and the connection point between the lower hanger of the hydraulic tilting cylinder and the frame. These points are the core channels for force transmission during the tilting process. Subsequently, a unit force or unit torque is applied to each degree of freedom (X / Y / Z translation and rotation) of these points to form an independent set of load conditions. Unlike the vibration condition, the frame is completely fixed to the ground, while the cab, as a floating body, retains its mass and center of mass moment of inertia to realistically simulate the reaction force of the rotating mass on the structure during the tilting process. Under different conditions, the inertia release algorithm is enabled, allowing the cab to achieve load balance solely through its own inertial force and structural elastic deformation without external constraints. Under this condition, the displacement, stress, and Gaussian integral point force response of each finite element in the vehicle body structure under a unit load are solved.

[0112] Optionally, the response calculation for the rigid connection between the lower support of the hydraulic tilting cylinder and the frame can be performed using linear static analysis, since this point is a fixed constraint end during the tilting process and there is no need for inertial release. However, the response still needs to be included in the overall response matrix.

[0113] Optionally, the aforementioned second inertia release result file is essentially the intrinsic compliance matrix of the structure under hydraulic tilting conditions. It can completely record how any unit load is transmitted through the structure and transformed into full-field stress when the cab is in a free tilting state. For example, when a +1000N Z-axis force is applied to the lifting lug of the hydraulic cylinder, the second inertia release result file records how this force is transmitted along the cab frame, causes stress concentration at the rear suspension bracket, induces tensile or shear deformation at the front suspension connection point, and what kind of reaction force distribution is generated at the lower support of the hydraulic cylinder. These response data do not contain any external constraint reaction forces and only reflect the true elastic response of the structure in a free-floating state, thus possessing extremely strong physical authenticity.

[0114] Optionally, after obtaining the second inertial release result file, the second time history load signal output by the multibody dynamics model is combined, that is, the curves of the six degrees of freedom force / torque changes with time at key points such as the hydraulic cylinder upper lug and the front / rear suspension connection points of the cab during the entire hydraulic rollover process (from unlocking → ejection → stagnation → descent → locking). Then, the matching process can proceed to the matching stage. The matching process can employ the principle of linear superposition. For example, the load vector at each moment is multiplied by the second inertial release response matrix, and the stress and strain responses of each unit in the entire vehicle at that instant are calculated point by point. Since the hydraulic rollover process typically lasts only a few seconds, the load changes drastically, but the total number of cycles (e.g., 300) is small, its transient peak value and nonlinear characteristics can still be fully preserved, accurately reproducing the impact of key events such as "the violent impact when the hydraulic cylinder initially ejects" and "the collision load at the moment of lock contact after the cab falls back" on the structure.

[0115] Optionally, the matching results are no longer a single maximum stress value, but rather a time-domain stress and strain amplitude evolution sequence for each element throughout the entire flipping process. This can realistically capture dynamic impact damage that is completely ignored by traditional static strength analysis. For example, a weld may have a stress of only 120 MPa in static analysis, but its peak stress reaches 280 MPa at the moment of flipping impact. Although the duration is only 0.1 seconds, due to the low-cycle fatigue characteristics of the material, this is enough to cause significant damage accumulation.

[0116] In this embodiment, after obtaining the road load spectrum of the vehicle under vibration conditions, the second load of the vehicle under hydraulic rollover conditions, and determining the first load caused by the vehicle's mass inertia based on the road load spectrum, the first and second loads can be matched to determine the stress amplitude distribution of different units in the vehicle over time as a function of the first and second loads, as well as the strain amplitude of the materials constituting the vehicle under the coupled action of the first and second loads. This allows for the determination of the linear superposition of damage under vibration and hydraulic rollover conditions, further determining the vehicle's durability performance indicators. This embodiment overcomes the limitations of related technologies that consider only a single operating condition and determine only a single damage, leading to errors in the determination of durability performance indicators. It thus solves the technical problem of not being able to effectively determine the vehicle's durability performance indicators, achieving the technical effect of effectively determining the vehicle's durability performance indicators.

[0117] The technical solutions of the embodiments of this application will be illustrated below with reference to preferred embodiments.

[0118] Currently, vehicle bodies (such as commercial vehicles) must withstand not only road vibration loads but also the reciprocating impact loads from the cab tilting during engine maintenance. Under these complex load conditions, OEMs often experience fatigue cracking of the vehicle body and hydraulic tilting system during product development and user operation, which can seriously affect occupant safety. This is due to the lack of effective durability control during the early stages of vehicle development.

[0119] In related technologies, durability control methods for vehicle bodies and hydraulic tilting systems often involve full-vehicle durability testing at test tracks or bench simulation tests. These methods require the production of prototype vehicles and parts, and often result in late problem identification, lacking effective guidance for structural improvements. The simulation analysis of vehicle bodies and hydraulic tilting systems mainly presents the following issues.

[0120] For the vehicle body system, although multibody dynamics modeling and virtual load iteration techniques are used to solve for the external loads on the vehicle body and thus conduct life prediction, these loads are mainly based on multiple suspension support points, neglecting the forces generated by the hydraulic tilting system, especially the hydraulic cylinders, during their free stroke. However, due to the differences in the internal characteristics of the hydraulic tilting system, these forces can range from hundreds to tens of thousands of Newtons, which cannot be ignored in the structural durability assessment of the vehicle body and the hydraulic tilting system.

[0121] For hydraulic tilting conditions, the calculations are mostly based on quasi-static conditions, that is, the initial tilting force and initial pullback tensile force of the hydraulic cylinder. The ultimate strength of the hydraulic cylinder support and the vehicle body structure is considered, but the load changes during the entire hydraulic tilting dynamic process are not simulated, and fatigue life or cycle number cannot be calculated.

[0122] Currently, most analyses of vehicle body fatigue life are based on vibration conditions. However, throughout the entire product lifecycle, the lifespan of the vehicle body and hydraulic rollover system should be the coupled lifespan under road vibration conditions and hydraulic rollover conditions.

[0123] In summary, the relevant technologies have certain accuracy issues in predicting the fatigue life of vehicle bodies and hydraulic rollover systems, which makes it impossible to fully control the durability of vehicle structures.

[0124] To address the aforementioned issues, this application proposes a durability simulation method for a vehicle body and hydraulic tilting system. Using test sensor signals from the cab, suspension, and hydraulic tilting system on a reliability verification road surface as the target, a multibody dynamics model of the system, including the cab, frame, suspension, and hydraulic tilting mechanism, is established as the transfer function to inversely calculate the drive input at the frame end. The time-domain history loads applied to the vehicle body and hydraulic tilting system are obtained. Then, based on vibration conditions, the durability of the vehicle body and supporting structure under the combined forces of the suspension system and hydraulic tilting system is examined, resolving the problem of incomplete load analysis for the durability of the vehicle body and related systems.

[0125] Furthermore, by simulating the full dynamic process of hydraulic tilting of the cab, the time-domain loads of the vehicle body's external interfaces and the time-domain loads of the input points of the tilting hydraulic cylinder brackets are output. This allows for the analysis of the durability of the vehicle body and its supporting structures during the hydraulic tilting process, thus resolving the life prediction accuracy issue inherent in static strength analysis methods for hydraulic tilting. Coupled calculations of structural fatigue damage caused by vibration and hydraulic tilting conditions address the accuracy issues in durability analysis of the vehicle body and hydraulic tilting system throughout the product's entire lifecycle.

[0126] Figure 2 This is a flowchart of a durability simulation method for a vehicle body and hydraulic rollover system according to an embodiment of this application, such as... Figure 2 As shown, it includes the following steps.

[0127] Step S201: Road load spectrum acquisition.

[0128] In this embodiment, load spectrum acquisition can be performed on reliable durability test pavement (e.g., vibration condition).

[0129] Figure 3 This is a schematic diagram of a sensor arrangement for road load spectrum testing according to an embodiment of this application, as shown below. Figure 3 As shown, these include 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, and 315.

[0130] In this embodiment, points 301, 302, 306, and 311 are measuring points on the upper support of the cab suspension, representing the vehicle body end, where three-way acceleration sensors can be installed. Points 308, 309, 313, and 314 are measuring points on the lower support of the cab suspension, representing the frame end, where three-way acceleration sensors can also be installed. Points 303, 307, 310, and 315 (dashed lines indicate directions), located between the upper and lower supports, can measure the axial relative displacement of the spring damper, where displacement sensors can be installed. For the hydraulic tilting actuator and support structure, three-way acceleration sensors can be installed on the upper support (305) and lower support (312) of the hydraulic cylinder, and displacement sensors (304) can be installed between the upper and lower lugs of the hydraulic cylinder. In addition, conventional GPS measurements, including vehicle speed, latitude, longitude, and altitude, can also be performed. The XYZ channel direction of the acceleration sensor should be consistent with the vehicle coordinate system used in the product design, while the displacement sensor specifies that tension is the positive direction and compression is the negative direction. The test vehicle can be a target vehicle or reference vehicle in good condition after a break-in period. The sampling rate should be 10 times the upper limit of the frequency range of interest (e.g., 0-50Hz), i.e., 500Hz. At least three cycles of road load signals can be obtained according to the required vehicle speed, and one cycle with the average standard deviation should be selected as the subsequent preprocessing signal.

[0131] Step S202, test signal analysis and processing.

[0132] In this embodiment, test signal analysis and processing can be performed. For example, using signal processing software (such as LMS.Tecware or Ncode Glyphworks), the vehicle speed of each road segment is first rigorously verified according to the reliability and durability test specifications. The actual vehicle speed is calculated using GPS or wheel speed signals and compared with the target vehicle speed to ensure that the speed deviation is no higher than 5%; otherwise, the data is deemed invalid and remeasured. Subsequently, the original signal can be preprocessed, using threshold detection and interpolation repair methods to remove glitches, correcting baseline offset caused by temperature drift using detrending or high-pass filtering techniques, and performing consistency checks on the left and right symmetrical channels to ensure that the signal correlation, amplitude magnitude, and response phase conform to physical logic. Based on this, typical operating conditions such as braking, steering, and driving over potholes can be captured, and the signal direction of each channel can be determined and adjusted according to the vehicle motion law to ensure that the polarity definition of the longitudinal, lateral, and vertical channels is correct. The system can further extract characteristic signals from typical road sections such as cobblestone roads, potholes, and washboard roads, maintaining strict time-domain synchronization across all channels. By precisely selecting zero points or applying smoothing window functions, the system processes the beginning and end of the signals to ensure that the sampled values ​​at the start and end points are equal to or close to zero. Finally, the processed signals can be standardized and named according to road section characteristics, and output as binary text files (ASCII Format, ASC), Recording Signal Protocol (RSP), Digital Acquisition Format (DAC), or Tecware binary files, while retaining complete channel names and physical unit information.

[0133] Step S203: Multibody dynamics modeling of the cab, suspension and hydraulic tilting system (vibration conditions).

[0134] In this embodiment, multibody dynamics modeling of the cab, suspension, and hydraulic tilting system can be performed.

[0135] Figure 4 This is a flowchart of a multibody dynamics modeling method according to an embodiment of this application, such as... Figure 4 As shown, it includes the following steps.

[0136] Step S401: Import the coordinate table of key hard points.

[0137] In this embodiment, software such as MSC.Adams or Simcenter3D Motion can be used to enter a multibody dynamics modeling environment. A table of key hardpoint coordinates for the cab, suspension, and hydraulic tilting system is imported. The key hardpoint coordinates are the coordinates of joints with connectivity relationships or the coordinates of response points of interest.

[0138] Step S402: Create the component object.

[0139] In this embodiment, based on the system's structural form, component objects can be created, mainly including the cab (including the upper suspension bracket and the upper support bracket of the tilting hydraulic cylinder), occupants and counterweights, the frame (or virtual clamps), stabilizer bars, the lower suspension bracket, hydraulic locks, the tilting hydraulic cylinder (including pistons and cylinder bodies), the lower support bracket of the hydraulic cylinder, connecting rods, sensors, virtual vibration tables, etc.

[0140] Step S403: Establish the force parameters of the shock absorber, spring, and bushing.

[0141] In this embodiment, the cab can be modeled in two ways: rigid body and flexible body. For a rigid body, the measured mass, center of mass, and moment of inertia need to be input. For a flexible body, the finite element model of the entire interior vehicle body (containing mass and stiffness information) is used. For the suspension system, elastic damping element units such as shock absorbers, springs, and bushing forces are created, and stiffness and damping curves are input. The upper and lower free travel of the shock absorber, the stiffness of the compression buffer block, and the stiffness curves of the tension limit block can also be defined. Similarly, for the tilting hydraulic cylinder, since it is similar to a damper, damping force units can be created, and bushing force units can be created at the upper and lower hangers.

[0142] Step S404: Establish kinematic pairs.

[0143] In this embodiment, kinematic pairs can be established, such as the cylindrical pair between the shock absorber piston and sleeve, the cylindrical pair between the piston and cylinder body of the tilting hydraulic cylinder, and the rotary pair between the cab and the hydraulic lock. The supports that bear the main loads, such as the cab suspension supports (including the front shock absorber lower support, the front stabilizer bar rear hinged lower support, and the rear suspension lower support), the stabilizer bar, and the tilting hydraulic cylinder lower support, are made more flexible.

[0144] Step S405: Make the suspension bracket flexible.

[0145] In this embodiment, the Craig Bampton method can be used for flexibility, extracting at least 10 vibration modes and static displacement compensation modes. The order of the static displacement compensation modes is determined by the number of external force direction channels, and a modal damping ratio is assigned.

[0146] In this embodiment of the application, multibody dynamics modeling is used to solve the inertial load of the cab on the vehicle body and hydraulic simulation system under vibration conditions. Therefore, the vehicle frame does not need to be modeled in a flexible manner and can be defined as a non-mass object.

[0147] Step S406: Establish a virtual vibration table.

[0148] In this embodiment, the virtual vibration table can be a Stuart-type vibration table. To obtain more accurate cab motion posture and fatigue load, a Stuart-type vibration table structure with more accurate inverse kinematics can be used.

[0149] Figure 5 This is a schematic diagram of a Stuart-type virtual vibration table according to an embodiment of this application, as shown below. Figure 5 As shown, there are 501, 502, 503, and 504. Among them, 501 can be used to represent a moving platform; 502 can be used to represent a ball joint; 503 can be used to represent a cylindrical joint; and 504 can be used to represent a fixed platform.

[0150] In this embodiment, the aforementioned Stuart-type virtual vibration table can be composed of a mobile platform 501, a fixed platform 504, six drive cylinders, and twelve ball joints 502. The fixed platform 504 is connected to the vehicle frame at its geometric center by a cylindrical joint 503. Two coordinate systems are established along the axis of each drive cylinder, belonging to the piston and the cylinder body respectively. The fixed platform 504 of the virtual vibration table frame is connected to the ground, constraining all degrees of freedom.

[0151] Step S407: Static balance calculation and preload adjustment.

[0152] In this embodiment, a static balance condition under the influence of gravity alone can be calculated to observe the displacement change of the spring damper. By adjusting the preload, the displacement of the spring damper can be maintained at the designed balance height to simulate the static balance characteristics of the air spring damper.

[0153] Step S408: System rigid body modal calculation.

[0154] In this embodiment, linearization identification can be performed, that is, the rigid body modes of the cab and suspension system can be calculated to see if there is a large difference from the measured or empirical values, and whether there are abnormal component motion postures, so as to further correct the model.

[0155] Step S409: Restart operating condition settings.

[0156] In this embodiment, the fully constrained connection between the fixed platform of the virtual vibration table and the ground can be released, a vibration condition can be established, and a joint solution can be performed with the static equilibrium condition. That is, a restart condition can be set to avoid the initial abnormal impact of the model due to the non-equilibrium state in subsequent iterative calculations. After that, the multibody dynamics model can be saved.

[0157] Step S204: Virtual load iteration and load decomposition.

[0158] In this embodiment, software such as structural fatigue life prediction software (Femfat) or virtual load iteration module (Motion TWR) is used to perform virtual load iteration and load decomposition.

[0159] Step S205: Finite element modeling and inertia release calculation under vibration conditions.

[0160] In this embodiment, finite element modeling and simulation software can be used to establish detailed finite element models of the entire interior vehicle body and the tilting hydraulic cylinder bracket. This includes operations such as component classification and naming, geometric structure cleaning, finite element mesh generation, modeling and assembly of bolts and welds, assignment of materials and properties, element quality checks, and weight information verification. At each force input point and channel of the vehicle body—namely, the connection point between the cab and the front and rear suspensions, and the connection point of the upper hanger of the tilting hydraulic cylinder—unit load cases can be established according to the load degrees of freedom. No constraints are applied to the model, and the inertia release calculation card in Nastran is used to establish load steps, outputting the element displacement, stress, and Gaussian integral point force results. Finite element analysis calculations can be performed, outputting OP2 format result files. For the tilting hydraulic cylinder bracket, at each force input point and channel—namely, the lower hanger of the tilting hydraulic cylinder, the lower bracket of the tilting hydraulic cylinder, and the fixing point to the frame—unit load cases are established according to the load degrees of freedom. No constraints are applied to the model, and the inertia release calculation card in Nastran is used to establish load steps, outputting the element displacement, stress, and Gaussian integral point force results. Perform finite element analysis calculations and output the result file in OP2 format.

[0161] Step S206, Vibration condition finite element results - load matching.

[0162] In this embodiment, a finite element-load matching set can be established, and an inertial release result file (corresponding to the first inertial release result file) and a time history load signal (corresponding to the first time history load signal) can be input. The result keyword header is used for matching (or manual matching) to obtain the full-field time-domain stress and strain amplitude of the vehicle body and hydraulic rollover system bracket under vibration conditions.

[0163] Step S207, single-cycle damage calculation under vibration conditions.

[0164] In this embodiment, single-cycle damage under vibration conditions can be calculated.

[0165] Step S208: Multibody dynamics modeling of the cab, suspension and hydraulic tilting system (hydraulic tilting condition).

[0166] In this embodiment, a multibody dynamics model of the hydraulic tilting system can be established. The main body utilizes the multibody dynamics model of the system under vibration conditions, with modifications made to this model. At this point, a virtual vibration table is no longer needed; the frame (or virtual clamp) is fixed to the ground. For the rigid or flexible body model of the cab, the passenger weight is removed. The connection between the cab and the hydraulic lock can be eliminated, for example, a cylindrical or rotary joint, simulating the unlocked state of the cab. The contact force between the "cylinder" (or sphere) and the "tension surface" can be established to simulate the contact behavior between the bolt and the lock body, such as Hertzian contact. Key parameters may include: the centerline position (or point) and diameter of the cylinder (or sphere), the maximum penetration depth of the object on the tension surface, the Hertzian or tangential transmission speed, the Young's modulus and Poisson's ratio of the two contacting objects, the coefficient of restitution, and the coefficient of friction. Based on the cylindrical joint between the piston and cylinder of the tilting hydraulic cylinder, a linear motion drive can be established, defining the drive function as a time-domain curve, including the displacement curves of the hydraulic cylinder's stretching, stagnation, and compression processes.

[0167] Step S209: Simulation and load decomposition of hydraulic overturning conditions.

[0168] In this embodiment, hydraulic rollover simulation and load decomposition can be performed. Load steps are set in a multibody dynamics environment, and calculations are performed to output the time-domain history loads of the cab and the connection points between the front and rear suspensions, and the cab and the upper support lug connection points of the hydraulic cylinders during the entire hydraulic rollover process, obtaining the fatigue loads on the vehicle body under hydraulic simulation conditions. For example, the load of the upper support of the hydraulic cylinders on the vehicle body in the main force directions (X and Z directions). Similarly, the time-domain history loads of the lower support lug connection points of the hydraulic cylinders are output to obtain the fatigue loads of the lower support of the hydraulic cylinders under hydraulic simulation conditions. The load at the hydraulic locking bolt of the rear suspension of the cab only has short-term impact loads during the initial tension of the hydraulic cylinder and the final fall of the cab; at other times, since the cab and the hydraulic lock are in a separated state, the load is 0.

[0169] Step S210: Calculation of inertia release and linear static calculation under hydraulic overturning conditions.

[0170] In this embodiment, finite element analysis of unit force load can be performed on the hydraulic tilting condition. Since the cab remains in a floating, unconstrained state under hydraulic tilting conditions, the inertial release method is also used for the vehicle body calculation. Unit load conditions are established according to the load degrees of freedom, and no constraints are applied to the model. The inertial release calculation card in Nastran software can be used to establish load steps and output the displacement, stress, and Gaussian integral point force results of the elements. Finite element analysis calculations are performed, and the results are output in OP2 format. For the lower support of the hydraulic cylinder, since one end is fixed to the frame, a linear static analysis method can be used. The fixed end of the frame is fully constrained, and static calculations are performed under unit load at each input point (mainly referring to the lower lug of the hydraulic cylinder), outputting the displacement, stress, and Gaussian integral point force results of the elements.

[0171] Step S211, Finite element results of hydraulic overturning condition - load matching.

[0172] In this embodiment, the finite element results (vehicle inertia release results, linear static analysis results of the hydraulic cylinder lower bracket) under hydraulic tilting conditions can be matched with the load. A finite element-load matching set can be established, and the inertia release results (corresponding to the second inertia release result file) or linear static analysis file and time history load signal (corresponding to the second time history load signal) are input. Matching is performed through the result keyword header (or manual matching) to obtain the full-field time-domain stress and strain amplitude of the vehicle body and hydraulic cylinder lower bracket under hydraulic tilting conditions.

[0173] Step S212, single-cycle damage calculation for hydraulic overturning condition.

[0174] In this embodiment, fatigue damage calculation of the structure can be performed using software such as Femfat or Simcenter3D Durability.

[0175] Step S213, total damage coupling calculation.

[0176] In this embodiment, total damage coupling calculation can be performed, where the total damage of any unit = Σ single-cycle damage under vibration conditions. Vibration cycle count + single-cycle damage under hydraulic tilting conditions The number of cycles under hydraulic tipping conditions. Post-processing using fatigue analysis software, combined with the test section length, can be converted into structural fatigue life and reliable durability mileage.

[0177] Figure 6 This is a flowchart of a virtual load iteration method according to an embodiment of this application, such as... Figure 6 As shown, it includes the following steps.

[0178] Step S601: Define the start and end frequencies, sampling rate, and frame length.

[0179] In this embodiment, a start and end frequency range can be defined, for example, 0.5-40Hz. The sampling rate and frame length can be set to ensure that the frequency resolution is <0.5Hz.

[0180] Step S602: Set up the sensor and actuator channels.

[0181] In this embodiment, a target sensor channel can be set, for example, Figure 3 The measurement points 301, 302, 305, 306, and 311 shown are the main target signal channels, each with three channels in the X, Y, and Z directions, totaling 15 channels. Measurement points 308, 309, 312, 313, and 314 are defined as auxiliary target signal channels, totaling 15 channels. At measurement points 303, 304, 307, 310, and 315, each relative displacement sensor establishes one channel, totaling 5 displacement channels, defined as auxiliary target signal channels.

[0182] Step S603: Input and adjustment of the target signal.

[0183] In this embodiment, within the virtual vibration table, six axial drive inputs can be established using the hydraulic cylinder body coordinate system and the piston coordinate system. The load spectrum signal of the input characteristic road surface is then used for channel-signal matching, and the signal is adjusted using a 0.5-40Hz bandpass filter.

[0184] Step S604: White-pink-red noise generation and FRF calculation.

[0185] In this embodiment, white-pink noise can be generated, and boundary frequencies can be set. Specifically, the area between the start frequency and the boundary frequency is defined as white noise, and the area between the boundary frequency and the end frequency is defined as pink noise. The curve exponent of the pink noise and the standard deviation of the driving signal can also be set. The white-pink noise can be used to drive a multibody dynamics model to obtain the frequency response function (FRF) between the driving and target signals.

[0186] Step S605, verification of the coherence function.

[0187] In this embodiment, the coherence function can be verified to ensure that it is greater than 0.5 between 0.5 and 1 Hz, and greater than 0.85 within the range of 1 to 40 Hz. Otherwise, the standard deviation of the drive, the boundary frequency, and the exponent of the pink noise curve are readjusted until the coherence meets the requirements.

[0188] Step S606, generation of the first driver.

[0189] In this embodiment, the first drive is generated by the input target signal of the characteristic road segment and the inverse function of the FRF, the multibody dynamics model is re-excited to obtain a response, and the response is compared with the root mean square (RMS) value of the target signal to obtain an error value. The error value is then corrected by the inverse function of the FRF.

[0190] Step S607, gain adjustment and iteration.

[0191] In this embodiment, the error, drive, and corresponding gain are continuously adjusted and iterated repeatedly.

[0192] Step S608: Iterative convergence judgment.

[0193] In this embodiment, iterative convergence can be determined.

[0194] Step S609: Stop iteration and output driver.

[0195] In this embodiment, when the RMS error percentage between the main target signal and the system response signal is less than 15% and the relative signal impairment is between 0.85 and 1.15, and the RMS error percentage between the auxiliary target signal and the system response signal is less than 25% and the relative signal impairment is between 0.5 and 2, iteration stops and displacement drive is output. Using the final displacement drive position as input, the multibody dynamics model is driven, outputting the time-domain loads of the front and rear suspension brackets of the cab and the upper bracket of the hydraulic tilting system, which serve as the load inputs for vehicle body durability simulation; the time-domain loads of the lower hanger of the tilting hydraulic cylinder, the lower bracket of the tilting hydraulic cylinder, and the fixed point of the frame are also output as the load inputs for the durability simulation of the tilting hydraulic support structure.

[0196] Figure 7 This is a schematic diagram of the time-domain load on the vehicle body support on the hydraulic cylinder under a rollover condition according to an embodiment of this application, as shown below. Figure 7 As shown, cab_yyg_up.asc-cab_yyg_up@+X represents the time-domain load signal of the cab suspension upper bracket in the longitudinal (front-to-back) direction of the vehicle, used to analyze the inertial impact and vibration response of the cab in the front-to-back direction. cab_yyg_up.asc-cab_yyg_up@+Z represents the time-domain load signal of the cab suspension upper bracket in the vertical (up-down) direction of the vehicle.

[0197] Figure 7The horizontal axis (Time in s-cab_yyg_up.asc) represents the time axis, with the unit being seconds (s), and originates from the sampling time series recorded in the file cab_yyg_up.asc. Here, cab represents the cab; yyg represents the hydraulic cylinder; up represents the "upper mount," the connection point between the cab and the upper mount of the hydraulic cylinder, which is connected to the cab body; and .asc represents ASCII text format used to store time-domain signal data (such as acceleration, force, displacement, etc.).

[0198] Figure 7 The vertical axis Z is used to represent the physical quantity of the cab suspension bracket in the Z direction.

[0199] Figure 8 This is a flowchart of a fatigue damage accumulation calculation method according to an embodiment of this application, such as... Figure 8 As shown, it includes the following steps.

[0200] Step S801, rainflow projection and filtering.

[0201] In this embodiment, software such as Femfat or Simcenter3D Durability can be used to insert a critical plane solution condition with 18 equally divided angles in a plane, based on the full-field time-domain stress and strain amplitude results of the vehicle body and hydraulic rollover system under vibration and hydraulic rollover conditions. The critical plane is found according to the tensor level and number. Based on the obtained critical plane, rainflow projection and filtering are performed, and all stress amplitudes are projected and recalculated according to their respective angles.

[0202] Step S802: Group according to material properties.

[0203] In this embodiment, the basic material parts structure can be grouped according to the metal material grade.

[0204] Step S803, Basic Material Fatigue Damage Analysis Module.

[0205] In this embodiment, for basic material parts structures, they can be grouped according to the metal material grade, enter the basic material fatigue damage analysis module, and select the strain-based fatigue life analysis method.

[0206] Step S804: Input parameters for strain life curve and cyclic stress-strain curve.

[0207] In this embodiment, strain-life curve parameters can be set, including elastic modulus, tensile strength, stress intensity coefficient, stress intensity exponent, toughness coefficient, and toughness exponent. Cyclic stress-strain curve parameters, including cyclic strength coefficient and cyclic strain hardening exponent, can also be set. All of the above parameters should be obtained through testing and fitting, or estimated using empirical formulas.

[0208] Step S805, Welding material fatigue damage analysis module.

[0209] In this embodiment, if a welding process, such as seam welding, is involved, the process proceeds to the welding material fatigue life analysis module.

[0210] Step S806: Determine the analysis method and input the fatigue curve.

[0211] In this embodiment, weld identification can be accomplished by examining two sheet metal parts with different attribute cards. Based on the welding angle and form, the weld can be identified as T-type, Y-type, L-type, lap joint, or butt joint. Using the notch stress method, the virtual notch radius is assigned based on thickness, and the main SN curve is defined using a sub-model method based on nodal forces and a weld joint notch stress database. For weld points, a Rupp-based force method or a structural stress method with a refined weld point model (reflecting weld nugget diameter, weld line, and heat-affected zone) is employed, also requiring a relatively accurate weld point SN curve.

[0212] Step S807, Mean stress correction and survival rate definition.

[0213] In this embodiment, for the basic structural material, the mean stress is corrected by selecting the P-SWT-based correction method (welding is almost unaffected by the mean stress and therefore does not require correction).

[0214] Step S808, surface condition and process parameters.

[0215] In this embodiment, the survival rate of the material fatigue curve can be defined according to the reliability verification standard, for example, 50% / 90% / 97.5%. The parameters can be modified according to the material surface roughness, whether or not a heat treatment process is involved, etc.

[0216] Step S809, Neuber elastoplastic correction.

[0217] In this embodiment, the Neuber nonlinear condition formula can be used in conjunction with cyclic stress-strain curves to perform elastoplastic correction.

[0218] Step S810, Minor damage accumulation rule selection.

[0219] In this embodiment, rainflow counting can be performed to obtain the number of cycles under different stress or strain amplitudes. Damage calculation and synthesis can be performed using the advanced linear damage accumulation rule (Elementary Minor) to obtain the single-cycle damage under vibration and hydraulic overturning conditions.

[0220] Step S811: Fatigue damage calculation and result post-processing.

[0221] In this embodiment, post-processing can be performed using fatigue analysis software, and the length of the test section can be converted into structural fatigue life and reliable durability mileage.

[0222] The user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of the relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0223] According to an embodiment of this application, a device for determining the durability performance index of a vehicle is also provided. It should be noted that this device for determining the durability performance index of a vehicle can be used to execute the method for determining the durability performance index of a vehicle in the embodiments.

[0224] Figure 9 This is a schematic diagram of a device for determining the durability performance index of a vehicle according to an embodiment of this application, as shown below. Figure 9 As shown, the device 900 for determining the durability performance index of the vehicle may include: an acquisition unit 902, a first determination unit 904, a matching unit 906, a second determination unit 908, and a third determination unit 910.

[0225] The acquisition unit 902 is used to acquire the road load spectrum of the vehicle under vibration conditions and the second load of the vehicle under hydraulic rollover conditions, wherein the road load spectrum is used to represent the load between the vehicle and the hydraulic rollover system of the vehicle.

[0226] The first determining unit 904 is used to determine the first load caused by the mass inertia of the vehicle based on the road load spectrum.

[0227] Matching unit 906 is used to perform matching processing on the first load and the second load to obtain matching results. The matching results are used to represent the stress amplitude distribution of different units in the vehicle in the time dimension as a function of the first load and the second load, as well as the strain amplitude of the material constituting the vehicle under the coupling action of the first load and the second load.

[0228] The second determining unit 908 is used to determine the linear superposition result of vehicle damage under vibration and hydraulic rollover conditions based on the matching results.

[0229] The third determining unit 910 is used to determine the vehicle's durability performance index based on the linear superposition result, wherein the durability performance index is used to represent the vehicle's fatigue life and durability performance mileage.

[0230] Optionally, the second determining unit 908 includes: a first determining subunit, used to determine a critical plane in the stress tensor space of different units in the vehicle by dividing it into target angles, wherein the critical plane is used to reflect the local damage concentration trend caused by the coupling effect of the first load and the second load; and a first processing subunit, used to perform projection processing and / or filtering processing on the matching results based on the critical plane to obtain an equivalent uniaxial strain amplitude and stress amplitude sequence consistent with the direction of the critical plane, and to group different units according to the material property information to obtain a metal material unit group and a welded structure unit group, wherein the metal material unit group is used to represent multiple non-welded structural components. The welded structure unit group is used to represent the connection area formed by welding; the second determination sub-unit is used to determine the number of cycles each finite element in different units undergoes under the matching result based on the equivalent uniaxial strain amplitude, stress amplitude sequence, metal material unit group and welded structure unit group; the third determination sub-unit is used to determine the initial damage based on the number of cycles and the linear cumulative damage rule, wherein the initial damage is used to represent the local fatigue damage value accumulated by the finite element under a single load cycle under vibration and hydraulic overturning conditions; the calculation sub-unit is used to perform coupled calculation on the initial damage to obtain the linear superposition result of the damage under vibration and hydraulic overturning conditions.

[0231] Optionally, the third determining unit 910 includes: a mapping subunit, used to perform three-dimensional mapping of the linear superposition result according to its spatial location to obtain a distribution cloud map of the linear superposition result, wherein the distribution cloud map is used to represent the three-dimensional distribution shape and gradient characteristics of the linear superposition result in space; a fourth determining subunit, used to determine the fatigue failure critical region corresponding to the linear superposition result based on the distribution cloud map, wherein the fatigue failure critical region is used to represent the structural location where the linear superposition result is greater than or equal to the threshold of the linear superposition result under the coupling action of the first load and the second load; and a fifth determining subunit, used to determine the fatigue life based on the fatigue failure critical region, and to determine the durability performance mileage based on the fatigue life and the length of the test section where the vehicle is located, wherein the fatigue life is used to represent the total number of cycles that the vehicle undergoes from zero damage accumulation to failure.

[0232] Optionally, the matching unit 906 includes: a first acquisition subunit, used to acquire a first inertial release result file under vibration conditions and a first time history load signal under vibration conditions, wherein the first inertial release result file is used to represent the displacement, stress, and Gaussian integral point force results calculated by inertial release when a unit load is applied to the first load under no external constraint conditions, and the first time history load signal is used to represent the simulated load signal borne by the vehicle's cab and hydraulic tilting system; and a first matching subunit, used to match the first load based on the first inertial release result file and the first time history load signal to obtain the matching result under vibration conditions.

[0233] Optionally, the first acquisition subunit includes: a second acquisition subunit, used to acquire the coordinates of key hard points in the cab, vehicle suspension system, and hydraulic tilting system, wherein the key hard point coordinates are used to represent the coordinates of joints with interconnected relationships or the coordinates of response points of interest; an application subunit, used to apply unit force and unit torque loads to the key hard point coordinates to obtain multiple sets of independent load conditions; a control subunit, used to control different units to balance external loads and inertial forces in a free state under load conditions to obtain the displacement, stress, and Gaussian integral point force results of different units under unit load; and a first output subunit, used to output the displacement, stress, and Gaussian integral point force results as a first inertia release result file.

[0234] Optionally, the first acquisition subunit includes: a third acquisition subunit for acquiring the initial signal of the vehicle under vibration conditions, wherein the initial signal represents the motion state of the vehicle running on road sections under different conditions; a second processing subunit for standardizing the initial signal to obtain a target signal; a second matching subunit for inputting the target signal into a multibody dynamics model for matching to obtain a driving signal, wherein the driving signal is obtained by the time-domain displacement function applied by the driving cylinder in the simulation platform; a sixth determination subunit for determining the frequency response functions of the target signal and the driving signal, wherein the frequency response function represents the linear transfer relationship between the displacement drive in the simulation platform and the target sensor response in the vehicle in the frequency domain; a second output subunit for outputting the displacement drive in response to the frequency response function satisfying the coherence function requirement and the error value of the target signal being less than the error value threshold, wherein the displacement drive represents the frequency domain excitation component corresponding to the time-domain displacement function; and a simulation subunit for inputting the displacement drive into the multibody dynamics model for simulation and outputting a first time history load signal.

[0235] Optionally, the matching unit 906 includes: a fourth acquisition subunit, used to acquire a second inertial release result file under hydraulic tilting conditions and a second time history load signal under hydraulic tilting conditions, wherein the second inertial release result file is used to represent the displacement, stress, and Gaussian integral point force results calculated by inertial release when a unit load is applied to the second load under no external constraint conditions, and the second time history load signal is used to represent the load sequence generated under hydraulic tilting conditions and when the vehicle's cab is in an unlocked state; and a third matching subunit, used to perform matching processing on the second load based on the second inertial release result file and the second time history load signal to obtain the matching result under hydraulic tilting conditions.

[0236] In this embodiment, the acquisition unit 902 acquires the road load spectrum of the vehicle under vibration conditions and the second load of the vehicle under hydraulic rollover conditions. The road load spectrum represents the load between the vehicle and the hydraulic rollover system. The first determination unit 904 determines the first load caused by the vehicle's mass inertia based on the road load spectrum. The matching unit 906 performs matching processing on the first load and the second load to obtain a matching result. The matching result represents the stress amplitude distribution of different units in the vehicle over time as a function of the first load and the second load, as well as the strain amplitude of the materials constituting the vehicle under the coupling effect of the first load and the second load. The second determination unit 908 determines the linear superposition result of the damage to the vehicle under vibration and hydraulic rollover conditions based on the matching result. The third determination unit 910 determines the vehicle's durability performance index based on the linear superposition result. The durability performance index represents the vehicle's fatigue life and durability mileage, thereby solving the technical problem of not being able to effectively determine the vehicle's durability performance index and achieving the technical effect of effectively determining the vehicle's durability performance index.

[0237] Embodiments of this application also provide an electronic device, including: a memory storing an executable program; and a processor for running the program, wherein the program executes the methods in various embodiments of this application when it runs.

[0238] Embodiments of this application also provide a computer-readable storage medium including a stored executable program, wherein, when the executable program is running, it controls the device where the computer-readable storage medium is located to perform the methods of various embodiments of this application.

[0239] Embodiments of this application also provide a computer program product, including a computer program that, when executed by a processor, implements the methods of various embodiments of this application.

[0240] Embodiments of this application also provide a computer program product, including a non-volatile computer-readable storage medium for storing a computer program that, when executed by a processor, implements the methods in various embodiments of this application.

[0241] Embodiments of this application also provide a computer program that, when executed by a processor, implements the methods described in the various embodiments of this application.

[0242] According to another aspect of the embodiments of this application, a vehicle is also provided. The vehicle includes a memory and a processor. The memory stores an executable program; the processor is used to run the program, which, when running, implements the methods described in the embodiments of this application.

[0243] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0244] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0245] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0246] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0247] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0248] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method of determining a durability index of a vehicle, characterized by, include: Obtain the road load spectrum of the vehicle under vibration conditions, and obtain the second load of the vehicle under hydraulic tipping conditions, wherein the road load spectrum is used to represent the load between the vehicle and the vehicle's hydraulic tipping system; Based on the road load spectrum, determine the first load caused by the mass inertia of the vehicle; The first load and the second load are matched separately to obtain a matching result, wherein the matching result is used to represent the stress amplitude distribution of different units in the vehicle in the time dimension as the first load and the second load change, and the strain amplitude of the materials constituting the vehicle under the coupled action of the first load and the second load; Based on the matching results, the linear superposition result of the damage to the vehicle under the vibration condition and the hydraulic rollover condition is determined; Based on the linear superposition result, the durability performance index of the vehicle is determined, wherein the durability performance index is used to represent the fatigue life and durability performance mileage of the vehicle.

2. The method of claim 1, wherein, Based on the matching results, the linear superposition of the damage to the vehicle under the vibration condition and the hydraulic rollover condition is determined, including: In the stress tensor space of the different units in the vehicle, a critical plane is determined by a target equally divided angle, wherein the critical plane is used to reflect the concentration trend of damage caused by the coupling effect between the first load and the second load; Based on the critical plane, the matching results are projected and / or filtered to obtain an equivalent uniaxial strain amplitude and stress amplitude sequence consistent with the direction of the critical plane. The different units are grouped according to the material property information to obtain a metal material unit group and a welded structure unit group. The metal material unit group is used to represent multiple non-welded structural components, and the welded structure unit group is used to represent the connection area formed by welding. Based on the equivalent uniaxial strain amplitude, the stress amplitude sequence, the metal material unit group and the welded structure unit group, determine the number of cycles each finite element in the different units undergoes under the matching result; Based on the number of cycles and the linear cumulative damage rule, the initial damage is determined, wherein the initial damage is used to represent the local fatigue damage value accumulated by the finite element element after a single load cycle under the vibration condition and the hydraulic overturning condition. The initial damage is coupled and calculated to obtain the linear superposition result of the damage under the vibration condition and the hydraulic overturning condition.

3. The method according to claim 1, characterized in that, Based on the linear superposition result, the durability performance index of the vehicle is determined, including: According to the spatial location, the linear superposition result is three-dimensionally mapped to obtain the distribution cloud map of the linear superposition result, wherein the distribution cloud map is used to represent the three-dimensional distribution shape and gradient characteristics of the linear superposition result in space; Based on the distribution cloud map, the fatigue failure critical region corresponding to the linear superposition result is determined, wherein the fatigue failure critical region is used to indicate the position where the linear superposition result is greater than or equal to the linear superposition result threshold under the coupling effect between the first load and the second load; The fatigue life is determined based on the fatigue failure critical region, and the durability performance mileage is determined based on the fatigue life and the length of the test section where the vehicle is located, wherein the fatigue life is used to represent the total number of cycles that the vehicle undergoes from zero damage to failure.

4. The method according to claim 1, characterized in that, The first load is subjected to matching processing to obtain matching results, including: The first inertial release result file and the first time history load signal under the vibration condition are obtained. The first inertial release result file is used to represent the displacement, stress and Gaussian integral point force results calculated by inertial release when a unit load is applied to the first load under no external constraint conditions. The first time history load signal is used to represent the simulated load signal borne by the cab of the vehicle and the hydraulic tilting system. Based on the first inertial release result file and the first time history load signal, the first load is matched to obtain the matching result under the vibration condition.

5. The method according to claim 4, characterized in that, The first inertial release result file under the vibration condition is obtained, including: The coordinates of key hard points in the cab, the vehicle's suspension system, and the hydraulic tilting system are obtained respectively, wherein the coordinates of key hard points are used to represent the coordinates of joints with a connection relationship or the coordinates of the response points of interest. Apply unit force and unit torque loads to the coordinates of the key hard points to obtain multiple sets of independent load conditions; Under the load condition, the different units are controlled to balance the external load and inertial force in a free state, and the displacement, stress and Gaussian integral point force results of the different units under the unit load are obtained. The displacement, stress, and Gaussian integral point force results are output as the first inertia release result file.

6. The method according to claim 4, characterized in that, Acquiring the first time history load signal under the vibration condition includes: Acquire the initial signal of the vehicle under the vibration condition, wherein the initial signal is used to represent the motion state of the vehicle when it is running on the road segment under the vibration condition; The initial signal is standardized to obtain the target signal; The target signal is input into a multibody dynamics model for matching to obtain a driving signal, wherein the driving signal is obtained by the time-domain displacement function applied by the driving cylinder in the simulation platform; Determine the frequency response functions of the target signal and the driving signal, wherein the frequency response functions are used to represent the linear transfer relationship between the displacement drive in the simulation platform and the target sensor response in the vehicle in the frequency domain; In response to the frequency response function satisfying the coherence function condition and the error value of the target signal being less than the error value threshold, the displacement drive is output, wherein the displacement drive is used to represent the frequency domain excitation component corresponding to the time domain displacement function; The displacement drive is input into the multibody dynamics model for simulation to obtain the first time history load signal.

7. The method according to claim 1, characterized in that, The second load is matched to obtain the matching result, including: Obtain the second inertia release result file under the hydraulic tilting condition and the second time history load signal under the hydraulic tilting condition. The second inertia release result file is used to represent the displacement, stress and Gaussian integral point force results calculated by inertia release when a unit load is applied to the second load under no external constraint conditions. The second time history load signal is used to represent the load sequence generated under the hydraulic tilting condition and when the vehicle's cab is in the unlocked state. Based on the second inertial release result file and the second time history load signal, the second load is matched to obtain the matching result under the hydraulic overturning condition.

8. A device for determining the durability performance indicators of a vehicle, characterized in that, include: The acquisition unit is used to acquire the road load spectrum of the vehicle under vibration conditions and to acquire the second load of the vehicle under hydraulic tipping conditions, wherein the road load spectrum is used to represent the load between the vehicle and the vehicle's hydraulic tipping system; The first determining unit is configured to determine, based on the road load spectrum, the first load caused by the mass inertia of the vehicle; A matching unit is used to perform matching processing on the first load and the second load respectively to obtain a matching result, wherein the matching result is used to represent the stress amplitude distribution of different units in the vehicle in the time dimension as the first load and the second load change, and the strain amplitude of the material constituting the vehicle under the coupled action of the first load and the second load; The second determining unit is used to determine, based on the matching result, the linear superposition result of the damage to the vehicle under the vibration condition and the hydraulic rollover condition; The third determining unit is used to determine the durability performance index of the vehicle based on the linear superposition result, wherein the durability performance index is used to represent the fatigue life and durability mileage of the vehicle.

9. An electronic device, characterized in that, include: Memory, which stores executable programs; A processor for running the program, wherein the program, when running, performs the method according to any one of claims 1 to 7.

10. A processor, characterized in that, The processor is used to run a program, wherein the program executes the method according to any one of claims 1 to 7 when it runs.

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