A method for evaluating the airdrop life of all-terrain vehicles

Abstract

The present invention relates to the technical field of vehicle airdrop life management and evaluation analysis, and in particular to an all-terrain vehicle airdrop life evaluation method. Firstly, an airdrop working condition simulation experiment is performed to obtain vibration impact input, and the obtained data is subjected to a global working condition load level distribution. Based on a calibrated whole vehicle finite element model, a multi-load fatigue simulation analysis is performed. A database mapping damage accumulation and remaining life of wearing parts is established according to the simulation experiment results. By collecting vehicle vibration functional component status information as real-time input and comparing it with database standards, matching calculation and real-time early warning of an on-board life management platform are realized. In this way, the technical problem that the all-terrain vehicle airdrop life evaluation method in the prior art is not perfect for the fatigue damage evaluation index system of the key structure of the airdrop vehicle, and there is also a large gap in real-time life prediction, which greatly affects the safety and long-term stability of the vehicle's three-dimensional maneuverability is solved.

Description

Technical Field

[0001] The invention relates to the technical field of vehicle airdrop life management and evaluation analysis, and in particular to an all-terrain vehicle airdrop life evaluation method. Background Art

[0002] Airdropping of all-terrain vehicles is an important condition for ensuring combat power. All-terrain vehicles dropped from helicopters and transport aircraft are subjected to large impact acceleration, and various structural and functional parts will suffer fatigue damage to varying degrees, shortening the service life of the all-terrain vehicles.

[0003] The prior art patent CN115563708A discloses an all-terrain vehicle airdrop life management and evaluation analysis method, which can evaluate the next airdrop capability of the all-terrain vehicle based on the evaluation results of the vehicle's appearance geometric parameters, the qualified rate of the reinforcement mooring points and the impact performance, but lacks the ability to evaluate the life of the all-terrain vehicle in real time;

[0004] The prior art patent CN115310042A discloses a vehicle airdrop life prediction method, device, special vehicle and storage medium. By obtaining the airdrop node of the equipment system, it further determines whether the airdrop and airborne capability meets the standards. However, the construction of the fatigue damage evaluation index system for different vehicle components is not perfect.

[0005] In summary, the existing all-terrain vehicle airdrop life assessment method does not have a perfect fatigue damage evaluation index system for the key structures of airdrop vehicles. At the same time, there is a large gap in real-time life prediction, which greatly affects the safety and long-term stability of the vehicle's three-dimensional maneuverability. Summary of the invention

[0006] The purpose of the present invention is to provide an all-terrain vehicle airdrop life assessment method, aiming to solve the technical problems that the all-terrain vehicle airdrop life assessment method in the prior art is not perfect for the fatigue damage evaluation index system of the key structure of the airdrop vehicle, and there is also a large gap in real-time life prediction, which greatly affects the safety and long-term stability of the vehicle's three-dimensional maneuverability.

[0007] To achieve the above object, the present invention adopts an all-terrain vehicle airdrop life assessment method, comprising the following steps:

[0008] First, impact acceleration simulation is performed on key parts of the vehicle;

[0009] Then, a mapping table of impact acceleration-vehicle structure fatigue damage value is established;

[0010] Finally, real-time assessment and early warning are made on the fatigue damage of the vehicle structure.

[0011] Among them, the impact acceleration simulation of key parts of the vehicle includes the design of an all-terrain vehicle airdrop simulation test plan and finite element simulation analysis modeling of airdrop conditions.

[0012] Among them, the specific method of designing the all-terrain vehicle airdrop simulation test plan is:

[0013] The vehicle landing impact process is simulated, and the impact acceleration values ​​of the key parts of the vehicle are recorded in this process. The worst part of the vehicle working condition is the vehicle landing impact process, with a peak acceleration of 20-30g and a duration of 200-300ms. The vehicle landing speed during airdrop is controlled at 6-8m / s, and impact acceleration tests are performed on the key parts of the vehicle.

[0014] Among them, in the finite element simulation analysis modeling of airdrop conditions:

[0015] Use finite element analysis software for body modeling and airbag modeling;

[0016] In terms of vehicle body modeling: use finite element analysis software (Hypermesh) to build a finite element model of the vehicle;

[0017] Among them, the door structure and the small external structural parts of the vehicle body have no effect on the falling condition and can be simplified or deleted; the engine parts are large in mass and affect the global weight distribution, so they are not deleted and are set as rigid units; the suspension part of the vehicle is set as a rigid body to ensure normal movement during the falling process; the layout of the vehicle is consistent with the test, the mass and center of gravity of the whole vehicle are calculated, and the weight is counterbalanced according to the theoretical center of gravity provided by the test vehicle to make its total weight reach 1.5t when fully loaded;

[0018] In terms of airbag modeling: based on the ideal gas uniform pressure model, the control volume method is used to establish the cushioning airbag system model.

[0019] Among them, based on the ideal gas uniform pressure model, when the control volume method is used to establish the cushioning airbag system model:

[0020] The airbag is meshed with shell elements, and the penalty function method is used to solve the airbag self-contact model and the contact model between the airbag and the ground, the vehicle body and the bottom plate.

[0021] After the vehicle body modeling and airbag modeling are completed, a rigid wall is built as the ground, and the contact with the tire, rim and lower fork arm of the suspension is established to simulate the contact between the vehicle and the airbag and the ground during the fall.

[0022] Then, numerical values ​​are set for the vehicle system's ground velocity and gravity acceleration, and finite element simulation is performed. The impact load results of vulnerable parts (such as wheels, horns, suspension arms and other load-bearing structural parts or functional parts) when the vehicle falls are obtained through simulation, and compared with the airdrop simulation experiment results to verify the accuracy of the finite element model;

[0023] At the same time, the obtained vehicle suspension load is loaded into the finite element model to simulate the impact load on the vehicle during the airdrop process. Based on the SN curve and MINER damage accumulation theory, data conditions are provided to support the next step of determining the airdrop impact life of each component.

[0024] Among them, the specific method of establishing the impact acceleration-vehicle structure fatigue damage value mapping table is:

[0025] Using fatigue life analysis software, based on finite element analysis results, fatigue life prediction is performed in the frequency domain and time domain to analyze the fatigue strength of key components of airdrop vehicles and determine the weakest position of component structural integrity;

[0026] The statistical distribution of the landing conditions of airdropped vehicles is analyzed, and based on the cumulative damage model (such as the SN curve and MINER damage accumulation theory), the cumulative damage of the vehicle structure after multiple landing impacts is studied. A load-life data mapping table is established, and the mapping relationship between the four-wheel variable amplitude impact load and the fatigue life of key vehicle parts is obtained.

[0027] Among them, when making real-time assessment and early warning of vehicle structure fatigue damage:

[0028] Integrate sensors in vehicle functional components to collect vehicle load and vibration data in real time, and transmit vehicle operation data (such as temperature, voltage, working status, etc.) to the data processing center in real time through the CAN network;

[0029] Establish a scientific life prediction model for special vehicles, combine real-time data and life algorithms to generate fault prediction results and corresponding maintenance recommendations;

[0030] Formulate a reasonable equipment inspection cycle, establish an equipment life database, and use big data, cloud computing, the Internet of Things and other technical means to achieve real-time monitoring and intelligent diagnosis of the status of special vehicles, promptly discover abnormal conditions of equipment, and prevent the occurrence of special vehicle failures.

[0031] Among them, the established special vehicle life prediction model estimates the fatigue life of the vehicle body structural components based on the fracture mechanics method, and conducts a comprehensive analysis based on working conditions, environmental conditions, and material factors.

[0032] The present invention provides an all-terrain vehicle airdrop life assessment method. The all-terrain vehicle airdrop simulation test scheme in the present invention has a relatively high-precision simulation capability, adopts a large number of force sensors, displacement sensors, multi-channel signal collectors, etc., and can accurately simulate various dynamic and environmental factors in the airdrop process, such as acceleration, aerodynamic force, ground impact, etc.; the simulation result can more realistically reflect the actual airdrop situation, and provide a real and reliable basis for subsequent tests;

[0033] In the process of establishing the simulation model of the airdrop drop of the all-terrain vehicle, the present invention compares the simulation data with the test vehicle response to determine an accurate finite element model of the whole vehicle; through fatigue analysis software simulation analysis, a fatigue damage value accumulation method for vehicle wearing parts under variable amplitude impact loading at different ground speeds is constructed, and the critical damage value is determined in combination with the actual use requirements of each component, which provides a reference value for practical application;

[0034] The present invention can evaluate and warn the fatigue damage of the vehicle structure in real time, and can comprehensively evaluate the test safety during the airdrop process. By collecting and analyzing the equipment operation data in real time, the real-time monitoring and intelligent diagnosis of the special vehicle status can be realized, and the abnormal conditions of the equipment can be discovered in time, and the occurrence of special vehicle failures can be prevented, which significantly improves the reliability of the vehicle and reduces the maintenance cost.

[0035] In this way, the technical problems that the existing all-terrain vehicle airdrop life assessment method has an imperfect fatigue damage evaluation index system for the key structures of the airdrop vehicle and there are also large gaps in real-time life prediction, which greatly affects the safety and long-term stability of the vehicle's three-dimensional maneuverability, are solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 It is a flow chart of the steps of the all-terrain vehicle airdrop life assessment method of the present invention.

[0038] Figure 2 It is a schematic diagram of a simulated ground impact test of a vehicle according to the present invention.

[0039] Figure 3 It is a simplified schematic diagram of the airdrop vehicle landing system of the present invention.

[0040] Figure 4 It is a flow chart of the structural cumulative damage calculation and evaluation process of the present invention.

[0041] Figure 5 This is a life prediction and evaluation flow chart of the present invention. DETAILED DESCRIPTION

[0042] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0043] See also Figure 1 to Figure 5 ,in Figure 1 is a flow chart of the steps of the all-terrain vehicle airdrop life assessment method of the present invention, Figure 2 This is a schematic diagram of a simulated vehicle landing impact test of the present invention. Figure 3 It is a simplified schematic diagram of the airdrop vehicle landing system of the present invention. Figure 4 This is a flow chart of the structural cumulative damage calculation and evaluation process of the present invention. Figure 5 This is a life prediction and evaluation flow chart of the present invention.

[0044] The present invention provides an all-terrain vehicle airdrop life assessment method, comprising the following steps:

[0045] S101, firstly, perform impact acceleration simulation on key parts of the vehicle;

[0046] For this specific implementation, it includes two steps: designing an all-terrain vehicle airdrop simulation test plan and finite element simulation analysis modeling of airdrop working conditions;

[0047] Specifically, the process of designing the all-terrain vehicle airdrop simulation test plan is as follows:

[0048] The test vehicle and the buffer system are packaged and bundled according to the requirements of the airdrop test, and connected to the special remote control release lock for impact using a crane arm. The airdrop vehicle system is lifted to a height of 3.2m above the ground, and the lifting points are selected around the vehicle body to keep the airdrop vehicle system horizontal in the air. Before the test vehicle is released, the buffer system airbag is already filled with air. The remote control release lock is remotely released, and the test vehicle freely falls and touches the ground. The entire airdrop process is recorded with a high-speed camera at a certain distance from the side of the vehicle body, with a camera speed of 800 frames / s.

[0049] like Figure 2As shown in the figure, the vehicle simulated landing impact test meets the following boundary conditions: the impact load of the test vehicle when it lands should be the maximum impact load in the airdrop, and the load acts vertically upward on the bottom deck; the test vehicle landing speed is 6-8m / s; the impact acceleration of the bottom deck of the vehicle body is ≤30g. In accordance with the requirements of test evaluation and data accumulation, the impact overload test installs a 40Hz low-pass filtered overload sensor at the specified position of the vehicle. The physical signal sensed by the sensor is converted into an electrical signal and transmitted to a data acquisition device with a sampling frequency of 1kHz for storage. Finally, the "time-overload" curve is obtained through special software.

[0050] The process of finite element simulation analysis and modeling of airdrop conditions is as follows:

[0051] When the experimental vehicle landed, the suspension, tires and airbags were the main buffer components. The suspension of the airdrop vehicle carries the suspended mass. During the fall impact, the damping elements exert a large reaction force on the vehicle body, which will produce a large acceleration peak after contact. The tires of the vehicle also carry non-suspension mass. At the same time, the springs of the vehicle will store a large amount of elastic potential energy during the compression process. When the vehicle body falls to the lowest point, the reaction force of the springs will cause the vehicle to maintain a high acceleration rebound. During the airdrop, the suspension and tires will have a certain amount of compression space, which plays a role in buffering and absorbing energy. The cargo platform also strengthens the buffering capacity of the airdrop vehicle.

[0052] like Figure 2 and Figure 3 As shown in the figure, no obvious deformation or fracture was found in the vehicle suspension after the airdrop, so it was set as a rigid body in the simulation. Use joint units to establish hinges to ensure that the suspension can move normally during the drop. Use *ELEMENT_DISCRETE units to simulate springs and damping, and ensure that the three one-dimensional units are in the same line. Use shell units to simulate the rubber cord composite material of the tire, and set the elastic modulus, Poisson's ratio and shear modulus. Finally, the vehicle is counterweighted to make the total weight reach 1.5t when fully loaded.

[0053] Based on the ideal gas uniform pressure model, the airbag model is established for the buffer system using the control volume method.

[0054] like Figure 2 and Figure 3 As shown in the figure, combined with the front all-terrain vehicle airdrop simulation test plan, the speed of the test vehicle when it falls freely until the tire touches the ground is about 6 to 8 m / s. The speed within this range is used as the variable ground initial velocity input, and the gravity acceleration of 9.8 m / s is input to the whole vehicle. 2 A rigid wall is established as the ground, and contacts with the tire, rim, and lower wishbone of the suspension are established to simulate the contact between the airdrop vehicle system and the ground during the fall.

[0055] like Figure 4As shown in the figure, after the finite element model of the airdrop vehicle-airbag system is established, the motion state and load boundary conditions are set for the simulation model. Based on the SN curve and the MINER damage accumulation theory, the fatigue life analysis software is used to establish a fatigue life prediction method for load-bearing structural parts or functional parts such as wheels, horns, and suspension arms.

[0056] like Figure 4 As shown in the figure, for the key structural analysis of the vehicle under airdrop conditions, it is necessary to establish the basic equations, where:

[0057] The basic equation of motion for impact dynamics is:

[0058] Ma+Cv+Kd=F e 1

[0059] Geometric equations describe the geometric relationship between deformation and motion of objects:

[0060] ε(x)=Bde 2

[0061] Constitutive equation, the material in this paper adopts the Johnson-Cook constitutive equation:

[0062]

[0063] Based on equations 1, 2, 3 and the finite element model, the calculation results of the structural dynamic response are obtained. Under the same impact load, the plastic strain value at the same position of the vehicle structure gradually increases in a certain trend. The test shows that under the same working condition of multiple landing impacts, the cumulative damage value of the structure is approximately linearly related to the number of landing impacts. The damage parameter is introduced to perform damage assessment calculation to determine whether the failure criterion is met. If the failure criterion is not met, the state is transferred, and a new round of calculation is performed based on the basic equation after the state is initialized; if the failure criterion is met, the cumulative damage result of the structural component or functional component is output, and the calculation ends.

[0064] S102, then establishing an impact acceleration-vehicle body structure fatigue damage value mapping table;

[0065] For this specific implementation mode, Figure 3 and Figure 4 As shown in the figure, based on the finite element model of the airdrop vehicle-airbag system, the landing condition of the airdrop vehicle is adjusted according to the experimental design plan, and its landing buffering process is simulated to analyze the distribution law of the peak acceleration of the frame, suspension, power transmission, vehicle on the vehicle and cargo platform mooring points during the landing buffering process. Based on the established cumulative damage model, the cumulative damage of the vehicle body structure after multiple landing impacts is studied. According to the numerical simulation, the fatigue analysis results of the airdrop loading condition are finally obtained, and the mapping relationship between the four-wheel variable amplitude impact load and the fatigue life of the vehicle's key parts is obtained, and the load-life data mapping table is established.

[0066] S103. Finally, make a real-time assessment and early warning of the fatigue damage of the vehicle body structure.

[0067] For this specific implementation mode, Figure 5 As shown in the figure, an all-terrain vehicle airdrop life assessment system is established. Based on the sensor data collection during the actual airdrop process of the vehicle and the load-life model knowledge base established through experimental verification, the system can monitor the fatigue life value of the key parts of the airdrop vehicle online, and provide fault diagnosis and fault warning through calculation and analysis, so as to realize the intelligent maintenance of the all-terrain vehicle under airdrop conditions.

[0068] In summary, the present invention first obtains vibration impact input through airdrop working condition simulation experiment, and distributes the acquired data in the global working condition load level. Based on the calibrated vehicle finite element model, multi-load fatigue simulation analysis is carried out, and a database mapping the damage accumulation and remaining life of wearing parts is established according to the simulation experiment results. In actual use, the acceleration sensor installed on the vehicle is used to collect the status information of the vehicle's vibration functional components as real-time input, and compared with the database standard to realize the matching calculation and real-time warning of the vehicle life management platform.

[0069] The all-terrain vehicle airdrop life assessment method of the present invention is used. The all-terrain vehicle airdrop simulation test scheme of the present invention has a relatively high-precision simulation capability, and adopts a large number of force sensors, displacement sensors, multi-channel signal collectors, etc., which can accurately simulate various dynamic and environmental factors in the airdrop process, such as acceleration, aerodynamic force, ground impact, etc.; the simulation results can more realistically reflect the actual airdrop situation, and provide a real and reliable basis for subsequent tests;

[0070] In the process of establishing the simulation model of the airdrop drop of the all-terrain vehicle, the present invention compares the simulation data with the test vehicle response to determine an accurate finite element model of the whole vehicle; through fatigue analysis software simulation analysis, a fatigue damage value accumulation method for vehicle wearing parts under variable amplitude impact loading at different ground speeds is constructed, and the critical damage value is determined in combination with the actual use requirements of each component, which provides a reference value for practical application;

[0071] The present invention can evaluate and warn the fatigue damage of the vehicle structure in real time, and can comprehensively evaluate the test safety during the airdrop process. By collecting and analyzing the equipment operation data in real time, the real-time monitoring and intelligent diagnosis of the special vehicle status can be realized, and the abnormal conditions of the equipment can be discovered in time, and the occurrence of special vehicle failures can be prevented, which significantly improves the reliability of the vehicle and reduces the maintenance cost.

[0072] In this way, the technical problems that the existing all-terrain vehicle airdrop life assessment method has an imperfect fatigue damage evaluation index system for the key structures of the airdrop vehicle and there are also large gaps in real-time life prediction, which greatly affects the safety and long-term stability of the vehicle's three-dimensional maneuverability, are solved.

[0073] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for evaluating the airdrop life of an all-terrain vehicle, characterized in that: The steps include: First, impact acceleration simulation is performed on key parts of the vehicle; Then, a mapping table of impact acceleration-vehicle structure fatigue damage value is established; Finally, real-time assessment and early warning are made on the fatigue damage of the vehicle structure.

2. The method for evaluating the airdrop life of an all-terrain vehicle according to claim 1, characterized in that: Impact acceleration simulation of key parts of the vehicle includes designing an all-terrain vehicle airdrop simulation test plan and finite element simulation analysis modeling of airdrop conditions.

3. The method for evaluating the airdrop life of an all-terrain vehicle as claimed in claim 2, characterized in that: The specific method of designing the all-terrain vehicle airdrop simulation test plan is: The vehicle landing impact process is simulated, and the impact acceleration values ​​of the key parts of the vehicle are recorded in this process. The worst part of the vehicle working condition is the vehicle landing impact process, with a peak acceleration of 20-30g and a duration of 200-300ms. The vehicle landing speed during airdrop is controlled at 6-8m / s, and impact acceleration tests are performed on the key parts of the vehicle.

4. The method for evaluating the airdrop life of an all-terrain vehicle as claimed in claim 3, characterized in that: In the finite element simulation analysis modeling of airdrop conditions: Use finite element analysis software for body modeling and airbag modeling; In terms of vehicle body modeling: use finite element analysis software to build a finite element model of the vehicle; Among them, the door structure and the small external structural parts of the vehicle body have no effect on the falling condition and can be simplified or deleted; the engine parts are large in mass and affect the global weight distribution, so they are not deleted and are set as rigid units; the suspension part of the vehicle is set as a rigid body to ensure normal movement during the falling process; the layout of the vehicle is consistent with the test, the mass and center of gravity of the whole vehicle are calculated, and the weight is counterbalanced according to the theoretical center of gravity provided by the test vehicle to make its total weight reach 1.5t when fully loaded; In terms of airbag modeling: based on the ideal gas uniform pressure model, the control volume method is used to establish the cushioning airbag system model.

5. The method for evaluating the airdrop life of an all-terrain vehicle according to claim 4, characterized in that: Based on the ideal gas uniform pressure model, when the control volume method is used to establish the cushioning airbag system model: The airbag is meshed with shell elements, and the penalty function method is used to solve the airbag self-contact model and the contact model between the airbag and the ground, the vehicle body and the bottom plate.

6. The method for evaluating the airdrop life of an all-terrain vehicle according to claim 5, characterized in that: After the vehicle body modeling and airbag modeling are completed, a rigid wall is built as the ground, and the contact with the tire, rim and lower fork arm of the suspension is established to simulate the contact between the vehicle and the airbag and the ground during the fall; Then, numerical values ​​are set for the vehicle system's ground velocity and gravity acceleration, and finite element simulation is performed. The impact load results of the vulnerable parts when the vehicle falls are obtained through simulation, and compared with the airdrop simulation experiment results to verify the accuracy of the finite element model; At the same time, the obtained vehicle suspension load is loaded into the finite element model to simulate the impact load on the vehicle during the airdrop process. Based on the SN curve and MINER damage accumulation theory, data conditions are provided to support the next step of determining the airdrop impact life of each component.

7. The method for evaluating the airdrop life of an all-terrain vehicle according to claim 6, characterized in that: The specific method of establishing the impact acceleration-vehicle structure fatigue damage value mapping table is as follows: Using fatigue life analysis software, based on finite element analysis results, fatigue life prediction is performed in the frequency domain and time domain to analyze the fatigue strength of key components of airdrop vehicles and determine the weakest position of component structural integrity; The statistical distribution of the landing conditions of airdropped vehicles was analyzed, and the cumulative damage of the vehicle structure after multiple landing impacts was studied based on the SN curve and MINER damage accumulation theory. A load-life data mapping table was established, and the mapping relationship between the four-wheel variable amplitude impact load and the fatigue life of key vehicle parts was obtained.

8. The method for evaluating the airdrop life of an all-terrain vehicle according to claim 7, characterized in that: When making real-time assessment and early warning of vehicle structure fatigue damage: Integrate sensors in vehicle functional components to collect vehicle load and vibration data in real time, and transmit vehicle operation data to the data processing center in real time through the CAN network; Establish a scientific life prediction model for special vehicles, combine real-time data and life algorithms to generate fault prediction results and corresponding maintenance recommendations; Formulate a reasonable equipment inspection cycle, establish an equipment life database, and use big data, cloud computing, the Internet of Things and other technical means to achieve real-time monitoring and intelligent diagnosis of the status of special vehicles, promptly discover abnormal conditions of equipment, and prevent the occurrence of special vehicle failures.

9. The method for evaluating the airdrop life of an all-terrain vehicle as claimed in claim 8, characterized in that: The established special vehicle life prediction model estimates the fatigue life of vehicle structure components based on the fracture mechanics method, and conducts a comprehensive analysis based on operating conditions, environmental conditions, and material factors.

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