Airdrop vehicle landing impact strength comprehensive detection method and device

Abstract

The invention discloses a comprehensive detection method for landing impact strength of an air-drop vehicle, which comprises the following steps of: constructing a simulation system through simulation software, setting an air-drop landing working condition, and carrying out air-drop landing impact simulation calculation; constructing a failure model of the component material; obtaining an impact simulation calculation result; performing an air-drop landing simulation test by using the sample vehicle, recording test data, comparing the test data with a simulation result, judging whether the accuracy meets the setting or not, if so, entering S30, and otherwise, entering S10; s20, combining the impact simulation calculation result corrected in the step S20 with the failure model constructed in the step S10 to judge whether the part is invalid, and if the part is invalid, S40; checking the effect of the buffer device, and if the buffer is insufficient, replacing the buffer device and merging into S10; if the vehicle strength is insufficient, a load transmission path is analyzed, and the step S50 is executed; carrying out simulation optimization iteration on the part with insufficient strength in the step S40, and completing the step S10; the invention further discloses a corresponding device. The strength performance of the vehicle can be accurately evaluated, the part with insufficient strength can be quickly positioned, and the corresponding part can be efficiently optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile performance detection, and in particular to a comprehensive detection method and device for the landing impact strength of an airdrop vehicle. Background Art

[0002] As an important tool for implementing long-range strategic deployment, airdropped vehicles rely on large transport aircraft to accurately deliver them to designated areas. However, at the moment when the parachute is untied and touches the ground, the airdropped vehicle will encounter an extreme and short-term impact load. This huge impact force is very likely to damage the vehicle structure, thereby threatening its combat effectiveness and mission execution capabilities. In order to alleviate this challenge, the industry generally integrates buffer devices at the bottom of airdropped vehicles. However, the use of buffer devices also introduces a series of new problems: because they are between the bottom of the vehicle and the ground, and the internal structure of the vehicle is complex, integrating many assemblies and components, which greatly increases the difficulty of quickly and comprehensively evaluating the overall strength of the vehicle. What is more difficult is that the landing process of airborne vehicles is extremely short, and the load impact it bears during this period is severe and the transmission path is intricate. This feature not only makes it almost impossible to immediately evaluate the strength of the vehicle, but also makes it difficult to quickly and accurately trace its root cause even if the problem appears, and then to optimize the vehicle structure in a targeted manner.

[0003] In order to solve this problem, some existing technologies have adapted existing tactical vehicles to airdrops, and cooperated with the manufacturers of the drop platforms to assemble buffer devices, and verified the strength of the airdrop vehicles through simulated airdrop tests. However, these technologies have some defects. For example, it is difficult to fully evaluate the strength of the vehicle, especially the unobservable parts; and because the simulated airdrop test has the characteristics of transient impact, short time, and strong destructiveness, it is difficult to diagnose the cause of the problem and optimize the direction.

[0004] In order to solve this problem, some existing technologies have proposed a simulation calculation method for the vehicle airdrop landing cushioning process based on nonlinear finite elements. By establishing a finite element model of the vehicle-airbag system for simulation calculation, the landing impact strength is evaluated. However, this technology has evaluation accuracy problems. Due to the complexity of the airdrop landing process, the coupling model of the vehicle and the cushioning device has not been experimentally calibrated, which will affect the accuracy of the simulation results. In addition, this technology lacks diagnostic and optimization methods. It only provides an evaluation method without mentioning how to diagnose the causes of the landing strength problems of airborne vehicles or how to optimize them, which limits its further improvement and accuracy improvement in practical applications. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a comprehensive detection method and device for the landing impact strength of an airdrop vehicle. Through simulation software, a comprehensive simulation system covering the interaction between the vehicle, the buffer device and the ground is constructed, and a variety of airdrop landing conditions are designed; at the same time, the GISSMO failure model is introduced to evaluate the damage of vehicle component materials; this system can not only accurately and comprehensively evaluate the strength performance of the vehicle, but also further verify the accuracy of the simulation model by comparing with the airdrop landing simulation test of the prototype vehicle; on this basis, the method can quickly diagnose the reasons for the substandard strength and quickly and accurately locate them, thereby improving the efficiency and pertinence of the optimization.

[0006] In order to achieve the above object, according to a first aspect of the present invention, a method for comprehensive detection of landing impact strength of an airdrop vehicle is provided, comprising the following steps:

[0007] S10, constructing a simulation system through simulation software to simulate the interaction between the vehicle and the buffer device and the interaction between them and the ground, then setting the airdrop landing condition, and carrying out the simulation calculation of the landing impact of the airdrop vehicle; at the same time, constructing the failure model of the vehicle component material;

[0008] S20, obtaining the impact simulation calculation result in S10; using the prototype vehicle to perform an airdrop landing simulation test, recording the test data and comparing it with the impact simulation calculation result, and judging whether the accuracy meets the set standard, if so, entering S30, otherwise returning to S10;

[0009] S30, evaluating the strength performance of each vehicle component and quantifying its redundancy through the impact simulation calculation result corrected in S20 and the failure model of the vehicle component material constructed in S10, and determining whether the component is failed. If it is failed, proceed to S40, otherwise, end;

[0010] S40, checking the buffering effect of the buffer device, if the buffering is insufficient, replacing the buffer device and re-entering S10; if the vehicle structure strength is insufficient, further analyzing the load transfer path and the insufficient strength parts, and then entering S50;

[0011] S50, performing simulation optimization iterations on the insufficient strength parts in S40, and re-entering S10 after the optimization is completed.

[0012] Furthermore, the method for constructing the simulation system in S10 is:

[0013] A vehicle-buffer device coupling finite element model is established in a computer through simulation software, wherein the finite element model includes a whole vehicle finite element model, a buffer device finite element model, a ground finite element model, a self-contact setting between the whole vehicle and the buffer device, a surface contact setting between the whole vehicle and the buffer device, and a surface contact setting between the whole vehicle-buffer device coupling model and the ground.

[0014] Furthermore, the method for setting the airdrop landing condition in S10 and carrying out the airdrop vehicle landing impact simulation calculation is:

[0015] Setting a variety of airdrop landing conditions, including a vertical landing condition and an oblique impact condition taking into account the influence of crosswind;

[0016] The method for carrying out the landing impact simulation calculation of the airdrop vehicle is to carry out the landing impact simulation calculation under each of the airdrop landing conditions in the explicit dynamics calculation software.

[0017] Furthermore, the method for constructing the failure model of the vehicle component material in S10 is:

[0018] The GISSMO failure model is used, which can define different failure strains under different stress triaxialities. A damage variable D is defined according to the model:

[0019]

[0020] D∈[0,1],

[0021] In the formula, εp is the equivalent plastic strain, εf is the equivalent plastic strain of fracture, η is the stress triaxiality, and n is the damage accumulation index. Initially, the damage variable D is 0. With continuous loading, the equivalent plastic strain εp of the material gradually increases, and the damage of the material also accumulates continuously. When the damage variable D=1, the material fails.

[0022] Furthermore, the S20 specifically includes the following steps:

[0023] S21, obtaining the impact simulation calculation result in S10, reading the landing impact simulation calculation result file under each airdrop landing condition in S10 through post-processing simulation software; obtaining the acceleration response curve at the key position of the vehicle, the stress-strain curve at the key position of the vehicle, and the speed change curve under the landing impact of the vehicle; outputting simulation data, wherein the simulation data includes the simulation model state, simulation condition, key position coordinates and simulation results;

[0024] S22, prototype vehicle preparation, conduct trial production of a simple vehicle that can match the buffer device. The simple vehicle refers to a functional prototype vehicle whose assembly interface with the buffer device is consistent with that of the mass-produced vehicle, and whose body stiffness and vehicle weight center of gravity are similar to those of the mass-produced vehicle. The functional prototype vehicle is used to provide feedback on the response characteristics of key components and key positions in the simulated airdrop landing test;

[0025] S23, using a prototype vehicle to conduct an airdrop landing simulation test, and separately conducting a simulated airdrop landing test of a buffer device to calibrate a simulation model of the buffer device, and measuring buffer parameters of the buffer device, wherein the buffer parameters include bag pressure and deformation; conducting a simulated airdrop test of a simple vehicle-buffer device, and measuring acceleration, stress strain and velocity change test data at corresponding working conditions and corresponding positions in the airdrop landing simulation model, for calibrating a vehicle finite element model;

[0026] S24, judging whether the accuracy meets the set standard, that is, the benchmarking of the airdrop vehicle landing impact simulation model, and performing benchmarking analysis on the impact simulation calculation results in S10 obtained in S21 and the test data in S23; if the benchmarking accuracy is lower than the set value, it is necessary to correct the vehicle or buffer device model, and then re-enter S10; if the benchmarking accuracy of the simulation result and the test result reaches the set value or above, the simulation result is credible and enters S30.

[0027] Furthermore, the method for determining whether a component fails in S30 is:

[0028] According to the index requirements of the landing impact life of the airdrop vehicle, the damage threshold of the component is formulated; if the damage variable D of the component is less than the damage threshold, the process ends; if D is greater than or equal to the damage threshold, the component is considered to have failed and enters S40.

[0029] Furthermore, the method for checking the buffering effect of the buffer device in S40 is:

[0030] S401, determining an acceleration threshold value and a speed threshold value of the vehicle according to test data;

[0031] S402, comparing the vehicle acceleration response in the impact simulation calculation result in S10 obtained in S21 with the acceleration threshold value, and comparing the rebound speed of touching the ground with the speed threshold value; if the acceleration response of the vehicle exceeds the acceleration threshold value or the rebound speed of touching the ground exceeds the speed threshold value, it is determined that the insufficient buffering effect of the buffer device is the reason why the vehicle strength does not meet the standard, and the buffer device is replaced and re-entering S10.

[0032] Furthermore, the specific steps of further analyzing the load transfer path and the insufficient strength parts in S40 are:

[0033] S410, if the acceleration response of the vehicle is lower than the acceleration threshold value and the rebound speed of the vehicle upon contacting the ground is lower than the speed threshold value, the weak structure of the vehicle is the reason why the strength of the airdrop vehicle does not meet the standard;

[0034] S420, analyzing the load transfer path of the airdrop vehicle during landing through post-processing simulation software; if the strength failure site appears on the load transfer path, and the cross-sectional force value on the transfer path changes suddenly, it is judged that the vehicle's skeleton structure is weak; if the strength failure site appears locally on the load transfer path or its periphery, and the cross-sectional force value on the transfer path does not change much, it is judged that the local structure of the vehicle is weak.

[0035] Furthermore, the method for performing simulation optimization iteration in S50 is:

[0036] When performing simulation optimization iterations on parts of the vehicle with insufficient strength, the key loads during the airdrop process are extracted as input for linear static mechanics calculations.

[0037] According to a second aspect of the present invention, there is provided a device for comprehensively detecting the landing impact strength of an airdrop vehicle, comprising:

[0038] Module 1: Use simulation software to build a simulation system to simulate the interaction between the vehicle and the buffer device and between them and the ground, then set up the airdrop landing conditions and carry out simulation calculations of the landing impact of the airdrop vehicle; at the same time, build a failure model of vehicle component materials;

[0039] The second module: obtaining the impact simulation calculation result in S10; using the prototype vehicle to perform an airdrop landing simulation test, recording the test data and comparing it with the impact simulation calculation result, and judging whether the accuracy meets the set standard, if so, entering S30, otherwise returning to S10;

[0040] The third module: through the impact simulation calculation results corrected in S20, combined with the failure model of the vehicle component material constructed in S10, the strength performance of each vehicle component is evaluated and its redundancy is quantified to determine whether the component fails. If it fails, enter S40, otherwise end;

[0041] The fourth module: check the buffering effect of the buffer device, if the buffering is insufficient, replace the buffer device and re-enter S10; if the vehicle structure strength is insufficient, further analyze the load transfer path and the insufficient strength parts, and enter S50;

[0042] The fifth module: perform simulation optimization iterations on the insufficient strength parts in S40, and re-enter S10 after the optimization is completed.

[0043] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0044] 1. The detection method of the present invention, through simulation software, constructs a comprehensive simulation system covering the interaction between vehicles, buffer devices and the ground, and designs a variety of airdrop landing conditions; at the same time, the GISSMO failure model is introduced to evaluate the damage of vehicle component materials; this system can not only accurately and comprehensively evaluate the strength performance of the vehicle, but also further verify the accuracy of the simulation model by comparing with the airdrop landing simulation test of the prototype vehicle; on this basis, the method can quickly diagnose the reasons for the substandard strength and quickly and accurately locate them, thereby improving the efficiency and pertinence of the optimization.

[0045] 2. The detection method of the present invention conducts an airdrop landing simulation test on a prototype vehicle, and compares the test data with the simulation results to ensure the accuracy of the simulation model; by continuously correcting the vehicle or buffer device model until the benchmarking accuracy of the simulation results and the test results reaches a set value or above, the accuracy of the simulation results is ensured, thereby being able to more accurately evaluate the strength performance of the vehicle, providing strong support for the formulation of optimization plans.

[0046] 3. After diagnosing the reasons for the substandard strength, the detection method of the present invention adopts an efficient optimization and iteration method. In the case of insufficient buffering of the buffer device, the buffer device is directly replaced and the simulation calculation is re-performed; in the case of insufficient vehicle structure strength, the load transfer path and the insufficient strength parts are analyzed, the key loads in the airdrop process are extracted as input, and linear static mechanical calculations are performed, and simulation optimization iterations are performed on the insufficient strength parts. This method not only improves the airdrop adaptability of the vehicle, shortens the optimization cycle, and avoids a large number of trial and error solutions in traditional methods, thereby reducing development costs; at the same time, by first carrying out optimization iterations under a linear static mechanical environment, and then using the optimized solution model to replace the original vehicle solution simulation model, the development efficiency is further improved, making the entire optimization process more efficient and economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A workflow diagram provided for a preferred embodiment of the present invention;

[0048] Figure 2 A schematic diagram of the structure of a comprehensive detection device for the landing impact strength of an airdrop vehicle provided in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In addition, the technical features in the various embodiments or single embodiments provided by the present invention can be arbitrarily combined with each other to form a feasible technical solution. This combination is not subject to the constraints of the sequence of steps and / or the structural composition mode, but must be based on the ability of ordinary technicians in this field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0050] Based on the above problems, the present invention proposes a comprehensive evaluation, diagnosis and optimization method for the landing impact strength of airdropped vehicles. The method follows a series of steps to achieve a comprehensive evaluation of the vehicle's strength performance, fault diagnosis and optimization scheme design. Overall, the technical solution effectively improves the vehicle's airdrop adaptability, reduces development costs, and shortens the development cycle.

[0051] First, the method uses simulation software to build a simulation system that can simulate the interaction between the vehicle and the buffer device and the ground. By setting up a variety of airdrop landing conditions, such as vertical landing and oblique impact conditions (considering the influence of crosswind), the method can evaluate the landing impact strength of the vehicle under different conditions. At the same time, by constructing a failure model of the vehicle component material, the method can predict the failure of the component under landing impact.

[0052] After obtaining the simulation calculation results, the method conducts an airdrop landing simulation test on a prototype vehicle and compares the test data with the simulation results to verify the accuracy of the simulation model. This process provides a reliable basis for subsequent evaluation and optimization.

[0053] Next, the method uses verified simulation calculation results and combines the failure model of vehicle component materials to comprehensively evaluate the strength performance of each vehicle component and quantify its redundancy. By determining whether a component has failed, the method can locate the cause of the substandard strength.

[0054] If the vehicle strength does not meet the standard, the method will check the buffering effect of the buffer device. If the buffering is insufficient, the buffer device will be replaced and the simulation calculation will be repeated. If the vehicle structure strength is insufficient, the load transfer path and the insufficient strength parts will be analyzed in depth to provide guidance for subsequent optimization.

[0055] Finally, the method simulates and optimizes the parts with insufficient strength iteratively. By extracting the key loads during the airdrop process as input and performing linear static mechanical calculations, the method can develop an optimization plan to improve the strength performance of the vehicle.

[0056] Specifically,

[0057] Please refer to Figure 1 The present invention relates to a comprehensive detection method for the landing impact strength of an airdrop vehicle, which specifically comprises the following steps:

[0058] S10, construct a simulation system through simulation software to simulate the interaction between the vehicle and the buffer device and the interaction between them and the ground, then set the airdrop landing condition, and carry out airdrop vehicle landing impact simulation calculation; at the same time, construct a failure model of vehicle component materials.

[0059] Carry out simulation calculation of landing impact of airdropped equipment

[0060] ① Finite element modeling of the whole vehicle-buffer device: a vehicle-buffer device coupling finite element model is established in a computer through simulation software, and the finite element model includes a whole vehicle finite element model, a buffer device finite element model, a ground finite element model, a self-contact setting inside the whole vehicle and the buffer device, a surface contact setting between the whole vehicle and the buffer device, and a surface contact setting between the whole vehicle-buffer device coupling model and the ground.

[0061] ②Construct the GISSMO failure model of vehicle component materials: The materials of the vehicle component finite element model are evaluated for failure using the GISSMO failure model. Generally, in automobile collision simulation technology, the constant strain failure criterion is used to evaluate strength failure. This is equivalent to using the failure characteristics of the material under uniaxial tensile stress to characterize the failure characteristics under all stress states, which is inconsistent with the actual situation. Compared with constant strain failure, the GISSMO failure model allows users to define different failure strains under different stress triaxialities. This model can better simulate the failure behavior of materials under complex stress states.

[0062] The GISSMO model defines a damage variable D∈[0,1]. The initial damage is 0. As the loading continues, the equivalent plastic strain of the material gradually increases, and the damage of the material also accumulates. When the damage value D=1, the material fails.

[0063] The GISSMO model defines the damage formula:

[0064] Where ε p is the equivalent plastic strain, ε f is the equivalent plastic strain at fracture, η is the stress triaxiality, and n is the damage accumulation index.

[0065] ③ Set the landing impact condition: In the simulation software, take the vehicle-buffer coupling model as the object and set the airdrop landing condition. The landing condition may include the normal vertical landing condition and the oblique impact condition considering the influence of crosswind. The landing condition should consider the worst case under the airborne vehicle landing scenario.

[0066] ④ Carry out simulation calculation of landing impact of airdropped vehicles: Carry out simulation calculation of landing impact under various airdrop impact conditions in explicit dynamics calculation software. The explicit dynamics calculation software can be a solver such as Radioss or LS-Dyna.

[0067] S20, obtaining the impact simulation calculation result in S10; using the prototype vehicle to perform an airdrop landing simulation test, recording the test data and comparing it with the impact simulation calculation result, and judging whether the accuracy meets the set standard, if so, entering S30, otherwise returning to S10;

[0068] Conduct benchmarking of airdrop vehicle landing impact simulation models

[0069] ① Obtain the simulation results of the landing impact of the airdrop vehicle: read the result files of the airdrop vehicle under various landing impact conditions through the post-processing simulation software Hyperview. Obtain the acceleration response curve at the key position of the vehicle, the stress-strain curve at the key position of the vehicle, and the speed change curve under the landing impact of the vehicle. Output the obtained simulation model status, simulation conditions, key position coordinates, simulation results and other information for benchmarking and verification with the test.

[0070] ② Conduct a simple vehicle airdrop landing simulation test: First, carry out a trial production of a simple vehicle that can match the buffer device. The simple vehicle refers to a functional prototype vehicle whose assembly interface between the vehicle and the buffer device is consistent with the mass-produced model, whose body stiffness is similar to the mass-produced model, and whose weight and center of gravity are similar to the mass-produced model. This functional prototype vehicle only needs to be able to feedback the response characteristics of key components and key positions in the simulated airdrop landing test. Next, a simulated airdrop landing test of the buffer device is carried out separately to measure parameters such as the bag pressure and deformation of the buffer device, which are mainly used to calibrate the simulation model of the buffer device. Finally, a simulated airdrop test of the simple vehicle-buffer device is carried out to measure the acceleration, stress strain, and velocity change test data at the corresponding working conditions and corresponding positions in the airdrop landing simulation model, which are used to calibrate the vehicle finite element model.

[0071] ③ Conduct benchmarking of airdrop vehicle landing impact simulation model: Conduct benchmarking analysis on the obtained airdrop landing simulation analysis results and test data. If the benchmarking accuracy is lower than the set value, the vehicle or buffer device model needs to be corrected, and then re-enter S10; if the benchmarking accuracy of the simulation result and the test result reaches the set value or above, the simulation result is credible and enters S30.

[0072] In some preferred embodiments, the accuracy setting value is 85%. If the benchmarking accuracy is lower than 85%, the vehicle or buffer device model needs to be corrected until the benchmarking accuracy exceeds 85%. If the benchmarking accuracy between the simulation result and the test result reaches more than 85%, the simulation result can be considered credible.

[0073] S30, evaluating the strength performance of each vehicle component and quantifying its redundancy through the impact simulation calculation result corrected in S20 and the failure model of the vehicle component material constructed in S10, and determining whether the component is failed. If it is failed, proceed to S40, otherwise, end;

[0074] Conducting landing impact strength assessment of airdropped vehicles

[0075] Through the high-precision airdrop landing simulation results obtained, the strength of the vehicle's airdrop interface, key components, etc. is evaluated. Through the vehicle's strength simulation results, the strength performance redundancy of each vehicle component is quantified, which can provide a theoretical basis for the vehicle's airdrop life assessment. Considering the index requirements of the airdrop vehicle landing impact life, the damage threshold of the component is formulated; if the damage variable D of the component is less than the damage threshold, it ends; if D is greater than or equal to the damage threshold, it is considered that the component has failed and enters S40.

[0076] In some preferred embodiments, the damage threshold is 0.2. If the damage D of the component is less than 0.2, the component strength is considered to meet the requirements and the design solution is considered to be passed; if the damage D of the component is greater than or equal to 0.2, the component is considered to be failed and the cause of the strength problem of the airdrop vehicle needs to be diagnosed and optimized.

[0077] S40, checking the buffering effect of the buffer device, if the buffering is insufficient, replacing the buffer device and re-entering S10; if the vehicle structure strength is insufficient, further analyzing the load transfer path and the insufficient strength parts, and then entering S50;

[0078] Conduct diagnosis of causes of airdrop vehicle strength issues

[0079] ① First, analyze the buffering characteristics of the buffer device during the airdrop landing process. If the acceleration response of the vehicle during the airdrop process exceeds the acceleration threshold value, and the rebound speed of the vehicle touching the ground exceeds the speed threshold value, it can be considered that the buffering effect of the buffer device is insufficient, causing the vehicle structure to absorb more impact energy, which is one of the main reasons why the strength of the airdrop vehicle does not meet the standard. At this time, the parameters or size optimization of the buffer device should be considered first, until the acceleration response and rebound speed of the vehicle are lower than the threshold value. If the acceleration and rebound speed of the vehicle during the airdrop process are both lower than the threshold value, it can be considered that the weak vehicle structure is the main reason for the vehicle's non-compliance with the strength standard.

[0080] ② After determining that the weak vehicle structure is the main reason for the airdrop vehicle's substandard strength, the load transfer path analysis during the landing of the airdrop vehicle was carried out through the post-processing simulation software Hyperview. If the strength failure site appears on a large area on the load transfer path, and the cross-sectional force value on the transfer path changes suddenly, it can be considered that the vehicle's weak skeleton structure is the main reason; if the strength failure site appears locally on the load transfer path or its periphery, and the cross-sectional force value on the transfer path does not change much, it can be considered that the local structural weakness of the vehicle is the main reason.

[0081] S50, performing simulation optimization iterations on the insufficient strength parts in S40, and re-entering S10 after the optimization is completed.

[0082] Carry out airdrop vehicle structure optimization

[0083] ① After determining the main reasons for the weakness of the vehicle structure, focus on simulation optimization iteration of the weak structure. Because the vehicle airdrop landing is a process of geometric nonlinearity, material nonlinearity, and boundary nonlinearity, the computer calculation time is very long. If the explicit dynamic calculation method is used for optimization iteration, the calculation efficiency is very low. However, if the cross-sectional load at the airdrop interface of the vehicle during the airdrop process is extracted as the load input for the optimization of the vehicle skeleton structure, and linear static mechanical calculations are carried out, the iterative efficiency of the optimization scheme will be greatly improved.

[0084] ② After the optimization of the vehicle skeleton structure and local structure is completed, the optimization scheme is replaced in the airdrop vehicle landing simulation model to carry out airdrop landing impact simulation analysis and verification of the vehicle-buffer device coupling model. If the strength of the optimization scheme meets the standard, the design scheme is passed. If the strength of the optimization scheme still does not meet the standard, continue to diagnose the cause and optimize the structural scheme until the vehicle strength meets the standard.

[0085] Please refer to Figure 2 As a second aspect of the present invention, it also relates to a comprehensive detection device for landing impact strength of an airdrop vehicle, comprising:

[0086] Module 1: Use simulation software to build a simulation system to simulate the interaction between the vehicle and the buffer device and between them and the ground, then set up the airdrop landing conditions and carry out simulation calculations of the landing impact of the airdrop vehicle; at the same time, build a failure model of vehicle component materials;

[0087] The second module: obtaining the impact simulation calculation result in S10; using the prototype vehicle to perform an airdrop landing simulation test, recording the test data and comparing it with the impact simulation calculation result, and judging whether the accuracy meets the set standard, if so, entering S30, otherwise returning to S10;

[0088] The third module: through the impact simulation calculation results corrected in S20, combined with the failure model of the vehicle component material constructed in S10, the strength performance of each vehicle component is evaluated and its redundancy is quantified to determine whether the component fails. If it fails, enter S40, otherwise end;

[0089] The fourth module: check the buffering effect of the buffer device, if the buffering is insufficient, replace the buffer device and re-enter S10; if the vehicle structure strength is insufficient, further analyze the load transfer path and the insufficient strength parts, and enter S50;

[0090] The fifth module: perform simulation optimization iterations on the insufficient strength parts in S40, and re-enter S10 after the optimization is completed.

[0091] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A comprehensive detection method for the landing impact strength of an airdrop vehicle, characterized in that: The following steps are involved: S10, constructing a simulation system through simulation software to simulate the interaction between the vehicle and the buffer device and the interaction between them and the ground, then setting the airdrop landing condition, and carrying out the simulation calculation of the landing impact of the airdrop vehicle; at the same time, constructing the failure model of the vehicle component material; S20, obtaining the impact simulation calculation result in S10; using the prototype vehicle to perform an airdrop landing simulation test, recording the test data and comparing it with the impact simulation calculation result, and judging whether the accuracy meets the set standard, if so, entering S30, otherwise returning to S10; S30, evaluating the strength performance of each vehicle component and quantifying its redundancy through the impact simulation calculation result corrected in S20 and the failure model of the vehicle component material constructed in S10, and determining whether the component is failed. If it is failed, proceed to S40, otherwise, end; S40, checking the buffering effect of the buffer device, if the buffering is insufficient, replacing the buffer device and re-entering S10; if the vehicle structure strength is insufficient, further analyzing the load transfer path and the insufficient strength parts, and then entering S50; S50, performing simulation optimization iterations on the insufficient strength parts in S40, and re-entering S10 after the optimization is completed.

2. The comprehensive detection method for landing impact strength of airdropped vehicles according to claim 1, characterized in that: The method for constructing the simulation system in S10 is: A vehicle-buffer device coupling finite element model is established in a computer through simulation software, wherein the finite element model includes a whole vehicle finite element model, a buffer device finite element model, a ground finite element model, a self-contact setting between the whole vehicle and the buffer device, a surface contact setting between the whole vehicle and the buffer device, and a surface contact setting between the whole vehicle-buffer device coupling model and the ground.

3. The comprehensive detection method for landing impact strength of airdropped vehicles according to claim 2, characterized in that: The method for setting the airdrop landing condition in S10 and carrying out the airdrop vehicle landing impact simulation calculation is as follows: Setting a variety of airdrop landing conditions, including a vertical landing condition and an oblique impact condition taking into account the influence of crosswind; The method for carrying out the landing impact simulation calculation of the airdrop vehicle is to carry out the landing impact simulation calculation under each of the airdrop landing conditions in the explicit dynamics calculation software.

4. The comprehensive detection method for landing impact strength of airdropped vehicles according to claim 1, characterized in that: The method for constructing the failure model of the vehicle component material in S10 is: The GISSMO failure model is used, which can define different failure strains under different stress triaxialities. A damage variable D is defined according to the model: D∈[0,1]， In the formula, ε p is the equivalent plastic strain, ε f is the equivalent plastic strain at fracture, η is the stress triaxiality, and n is the damage accumulation index; initially, the damage variable D is 0. As the loading continues, the equivalent plastic strain ε of the material increases. p As the damage variable D increases gradually, the material damage also accumulates. When the damage variable D=1, the material fails.

5. The comprehensive detection method for landing impact strength of airdropped vehicles according to claim 1, characterized in that: The S20 specifically includes the following steps: S21, obtaining the impact simulation calculation result in S10, reading the landing impact simulation calculation result file under each airdrop landing condition in S10 through post-processing simulation software; obtaining the acceleration response curve at the key position of the vehicle, the stress-strain curve at the key position of the vehicle, and the speed change curve under the landing impact of the vehicle; outputting simulation data, wherein the simulation data includes the simulation model state, simulation condition, key position coordinates and simulation results; S22, prototype vehicle preparation, conduct trial production of a simple vehicle that can match the buffer device. The simple vehicle refers to a functional prototype vehicle whose assembly interface with the buffer device is consistent with that of the mass-produced vehicle, and whose body stiffness and vehicle weight center of gravity are similar to those of the mass-produced vehicle. The functional prototype vehicle is used to provide feedback on the response characteristics of key components and key positions in the simulated airdrop landing test; S23, using a prototype vehicle to conduct an airdrop landing simulation test, and separately conducting a simulated airdrop landing test of a buffer device to calibrate a simulation model of the buffer device, and measuring buffer parameters of the buffer device, wherein the buffer parameters include bag pressure and deformation; conducting a simulated airdrop test of a simple vehicle-buffer device, and measuring acceleration, stress strain and velocity change test data at corresponding working conditions and corresponding positions in the airdrop landing simulation model, for calibrating a vehicle finite element model; S24, judging whether the accuracy meets the set standard, that is, the benchmarking of the airdrop vehicle landing impact simulation model, and performing benchmarking analysis on the impact simulation calculation results in S10 obtained in S21 and the test data in S23; if the benchmarking accuracy is lower than the set value, it is necessary to correct the vehicle or buffer device model, and then re-enter S10; if the benchmarking accuracy of the simulation result and the test result reaches the set value or above, the simulation result is credible and enters S30.

6. The comprehensive detection method for landing impact strength of airdropped vehicles according to claim 4, characterized in that: The method for determining whether a component is failed in S30 is: According to the index requirements of the landing impact life of the airdrop vehicle, the damage threshold of the component is formulated; if the damage variable D of the component is less than the damage threshold, the process ends; if D is greater than or equal to the damage threshold, the component is considered to have failed and enters S40.

7. The comprehensive detection method for landing impact strength of airdropped vehicles according to claim 5, characterized in that: The method for checking the buffering effect of the buffer device in S40 is: S401, determining an acceleration threshold value and a speed threshold value of the vehicle according to test data; S402, comparing the vehicle acceleration response in the impact simulation calculation result in S10 obtained in S21 with the acceleration threshold value, and comparing the rebound speed of touching the ground with the speed threshold value; if the acceleration response of the vehicle exceeds the acceleration threshold value or the rebound speed of touching the ground exceeds the speed threshold value, it is determined that the insufficient buffering effect of the buffer device is the reason why the vehicle strength does not meet the standard, and the buffer device is replaced and re-entering S10.

8. The comprehensive detection method for landing impact strength of airdropped vehicles according to claim 7, characterized in that: The specific steps of further analyzing the load transfer path and the insufficient strength parts in S40 are: S410, if the acceleration response of the vehicle is lower than the acceleration threshold value and the rebound speed of the vehicle upon contacting the ground is lower than the speed threshold value, the weak structure of the vehicle is the reason why the strength of the airdrop vehicle does not meet the standard; S420, analyzing a load transfer path during the landing of the airdrop vehicle by using post-processing simulation software; If the strength failure site appears on the load transfer path and the cross-sectional force value on the transfer path changes suddenly, it is judged that the vehicle's skeleton structure is weak; if the strength failure site appears locally on the load transfer path or its periphery and the cross-sectional force value on the transfer path does not change much, it is judged that the vehicle's local structure is weak.

9. The comprehensive detection method for landing impact strength of airdropped vehicles according to claim 1, characterized in that: The method for carrying out simulation optimization iteration in S50 is: When performing simulation optimization iterations on parts of the vehicle with insufficient strength, the key loads during the airdrop process are extracted as input for linear static mechanics calculations.

10. A comprehensive detection device for the landing impact strength of an airdrop vehicle, characterized in that: include: Module 1: Use simulation software to build a simulation system to simulate the interaction between the vehicle and the buffer device and between them and the ground, then set up the airdrop landing conditions and carry out simulation calculations of the landing impact of the airdrop vehicle; at the same time, build a failure model of vehicle component materials; The second module: obtaining the impact simulation calculation result in S10; using the prototype vehicle to perform an airdrop landing simulation test, recording the test data and comparing it with the impact simulation calculation result, and judging whether the accuracy meets the set standard, if so, entering S30, otherwise returning to S10; The third module: through the impact simulation calculation results corrected in S20, combined with the failure model of the vehicle component material constructed in S10, the strength performance of each vehicle component is evaluated and its redundancy is quantified to determine whether the component fails. If it fails, enter S40, otherwise end; The fourth module: check the buffering effect of the buffer device, if the buffering is insufficient, replace the buffer device and re-enter S10; if the vehicle structure strength is insufficient, further analyze the load transfer path and the insufficient strength parts, and enter S50; The fifth module: perform simulation optimization iterations on the insufficient strength parts in S40, and re-enter S10 after the optimization is completed.

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