A design method based on FRB and MPDB high-speed collision mode

Abstract

The application discloses a design method based on FRB and MPDB high-speed collision mode, and belongs to the technical field of automobile collision analysis models, and comprises the following steps: acquiring equivalent stiffness of a restraint system, an energy absorption space of a front end of a vehicle body, a topological structure of the front end of the vehicle body, a total vehicle mass, and mass and equivalent stiffness of MPDB; the equivalent stiffness of the restraint system and the energy absorption space of the front end of the vehicle body are used to obtain FRB working condition passenger safety evaluation indexes by adopting an FRB analysis method; MPDB working condition vehicle compatibility evaluation indexes are obtained by adopting an MPDB analysis method; the FRB working condition passenger safety evaluation indexes are used as optimization targets, and the MPDB working condition vehicle compatibility evaluation indexes are used as constraint conditions, so that optimal parameters of each front end substructure of the vehicle body are obtained, thereby providing guidance for high-speed collision scheme design. The application locks the structure parameters and performance parameters of a vehicle body component and a safety system component, and realizes positive front collision performance and one-time development of a vehicle body structure.

Description

Technical Field

[0001] The invention discloses a design method based on FRB and MPDB high-speed collision modes, belonging to the technical field of automobile collision analytical models. Background Art

[0002] With the advancement of passive safety technology, the requirements for vehicle collision safety technology are becoming increasingly stringent, and the types of collisions simulated during development are becoming increasingly similar to actual traffic accident scenarios. Currently, the most widely used and important test evaluation methods for high-speed frontal collisions in vehicle development are the FRB and MPDB evaluation methods. Because the MPDB evaluation method is the latest evaluation method, previous design methods either focused solely on body structure design for FRB conditions or used finite element simulation to control the magnitude of the vehicle's collision acceleration at the lower end of the B-pillar and generate a broadband signal as the collision waveform. The drawbacks of these methods are that they cannot comprehensively consider multiple collision conditions during design, and secondly, they require at least a partial body structure to be available before simulation analysis can be performed. Summary of the Invention

[0003] The purpose of the present invention is to solve the problem that the current frontal high-speed collision mode test evaluation method cannot take into account multiple collision conditions for joint design, and secondly, at least part of the vehicle body structure must be available before simulation analysis can be carried out. A design method based on FRB and MPDB high-speed collision modes is proposed.

[0004] The problem to be solved by the present invention is achieved by the following technical solutions:

[0005] A design method based on the FRB and MPDB high-speed collision modes, comprising:

[0006] Obtain the equivalent stiffness of the restraint system, the energy absorption space of the front end of the vehicle body, the topological structure of the front end of the vehicle body, the mass of the vehicle, and the mass and equivalent stiffness of the MPDB respectively;

[0007] The equivalent stiffness of the restraint system and the energy absorption space at the front end of the vehicle body are obtained by adopting the FRB analytical method to obtain the FRB working condition occupant safety evaluation index;

[0008] The MPDB working condition vehicle compatibility evaluation index is obtained by using the MPDB analytical method based on the front end energy absorption space of the vehicle body, the front end topology of the vehicle body, the vehicle mass, and the mass and equivalent stiffness of the MPDB;

[0009] Taking the occupant safety evaluation index of the FRB working condition as the optimization target and the vehicle compatibility evaluation index of the MPDB working condition as the constraint condition, the optimal parameters of each vehicle front terminal structure are obtained, providing guidance for the design of high-speed collision schemes.

[0010] Preferably, the equivalent stiffness of the restraint system and the front energy absorption space of the vehicle body are used to obtain the FRB working condition occupant safety evaluation index by adopting the FRB analytical method, including:

[0011] An equivalent double-step wave curve is obtained through the energy-absorbing space at the front end of the vehicle body;

[0012] The FRB analytical method is used to obtain the occupant safety evaluation index of the FRB working condition through the equivalent double-step wave curve and the equivalent stiffness of the restraint system.

[0013] Preferably, the equivalent double-step wave curve includes: taking the collision time as the horizontal axis and the vehicle acceleration as the vertical axis, simplifying the vehicle collision acceleration time history into a double-step wave curve.

[0014] Preferably, the whole vehicle collision acceleration time history includes, in sequence: the initial moment of the collision, the moment when the front bumper beam hits the rigid wall, the moment when the engine hits the rigid wall, the moment when the whole vehicle speed returns to zero, and the moment when the whole vehicle collision acceleration returns to zero.

[0015] Preferably, the FRB working condition occupant safety evaluation index is obtained by using the equivalent double-step wave curve and the equivalent stiffness of the restraint system using the FRB analytical method, including:

[0016] The equivalent double-step wave curve and the equivalent stiffness of the restraint system are used to obtain the FRB operating condition occupant safety evaluation index according to formula (1) and formula (2):

[0017]

[0018] a omax =max(a o ) (2)

[0019] Where: d o and d v are the displacements of the occupant and the vehicle respectively, k is the equivalent stiffness of the restraint system, v o is the passenger speed, a o is the occupant acceleration, z is the number of iterations, ΔT is the time interval between each iteration, and the evaluation index of occupant safety is a omax .

[0020] Preferably, the front-end energy absorption space of the vehicle body, the front-end topology of the vehicle body, the mass of the vehicle, and the mass and equivalent stiffness of the MPDB are obtained by adopting the MPDB analytical method to obtain the MPDB working condition vehicle compatibility evaluation index, including:

[0021] The equivalent double-step wave curve and the front-end topological structure of the vehicle body are decomposed by using the double-step wave target to obtain the energy absorption and deformation of the front-end terminal structure of the vehicle body;

[0022] The energy absorption and deformation of the front terminal structure of the vehicle body, the mass of the vehicle, and the mass and equivalent stiffness of the MPDB are obtained by adopting the MPDB analytical method to obtain the MPDB working condition vehicle compatibility evaluation index.

[0023] Preferably, the equivalent double-step wave curve and the vehicle front end topology structure are decomposed by using the double-step wave target to obtain the energy absorption and deformation of the vehicle front terminal structure, including:

[0024] The deformation sequence of the substructure, the longitudinal deformation space, the proportion of the substructure's energy absorption space in the YZ plane, and the energy absorption proportion of the front terminal structure are obtained through the front-end topological structure of the vehicle body;

[0025] The energy absorption and deformation of the front terminal structure of the vehicle body are determined by the deformation sequence of the substructure, the longitudinal deformation space, the energy absorption ratio of the front terminal structure and the equivalent double-step wave curve.

[0026] Preferably, the determining of the energy absorption and deformation of the front terminal structure of the vehicle body by using the longitudinal deformation space, the energy absorption ratio of the front terminal structure and the equivalent double-step wave curve includes:

[0027] The double-step wave curve obtained by the deformation sequence of the equivalent double-step wave curve and the substructure is longitudinally segmented into i segments, and the energy absorption of the front terminal structure of the vehicle body is obtained by formula (3):

[0028]

[0029] Wherein, avi is the amplitude of the double-step wave at the i-th segment, βij is the energy absorption ratio of the j-th front terminal structure, aij is the acceleration of the front terminal structure of the vehicle body, and the integral of the product of the acceleration and the structural mass with the deformation is the energy absorption of the front terminal structure of the vehicle body;

[0030] The deformation amount of the vehicle body front terminal structure is obtained through the longitudinal deformation space.

[0031] Preferably, the energy absorption and deformation of the front terminal structure of the vehicle body, the mass of the vehicle, and the mass and equivalent stiffness of the MPDB are obtained by adopting the MPDB analytical method to obtain the MPDB working condition vehicle compatibility evaluation index, including:

[0032] The equivalent stiffness between the vehicle and the barrier is obtained by the equivalent stiffness of the MPDB and the proportion of the energy absorption space of the substructure in the YZ plane;

[0033] The relative displacement between the barrier and the vehicle is obtained by the equivalent stiffness between the vehicle and the barrier, the vehicle mass, the acceleration of the front terminal structure of the vehicle body, and the mass of the MPDB;

[0034] The MPDB working condition vehicle compatibility evaluation index is obtained through the relative displacement between the barrier and the vehicle, the equivalent stiffness between the vehicle and the barrier, and the equivalent double-step wave curve. The MPDB working condition vehicle compatibility evaluation index includes: the MPDB occupant load index, maximum deformation and deformation standard deviation.

[0035] Preferably, the MPDB working condition vehicle compatibility evaluation index obtained by the relative displacement between the barrier and the vehicle, the equivalent stiffness between the vehicle and the barrier, and the equivalent double-step wave curve includes:

[0036] Obtaining the MPDB occupant load index through the equivalent double-step wave curve;

[0037] The maximum deformation of the MPDB is obtained by the relative displacement between the barrier and the vehicle and the equivalent stiffness between the vehicle and the barrier;

[0038] The deformation standard deviation of the MPDB is obtained by the maximum deformation of the MPDB.

[0039] The present invention has the following beneficial effects compared with the prior art:

[0040] The present invention discloses a design method based on FRB and MPDB high-speed collision modes. In the conceptual design stage of a vehicle, under the conditions that the equivalent stiffness of the restraint system, the energy absorption space of the front end of the vehicle body, the topological structure of the front end of the vehicle body, the mass of the entire vehicle, and the mass and equivalent stiffness of the MPDB are known, empirical and analytical methods are used to obtain evaluation indicators of FRB and MPDB working conditions through four steps: double-step wave definition, double-step wave target decomposition, FRB analytical method, and MPDB analytical method. Subsequently, key design parameters of the substructure are obtained through a structural parameter optimization method, and performance parameters of the substructure are obtained through a structural parameter optimization method. This method realizes the joint design of the vehicle body structure for the two frontal collision types in the conceptual design stage, and can lock the structural parameters and performance parameters of the vehicle body components and safety system components, thereby realizing forward and one-time development of the frontal collision performance of the vehicle body structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a flow chart of a design method based on the FRB and MPDB high-speed collision modes of the present invention.

[0042] Figure 2 This is an equivalent double-step wave curve diagram of a design method based on the FRB and MPDB high-speed collision modes of the present invention.

[0043] Figure 3 This is a front-end space diagram of a design method based on the FRB and MPDB high-speed collision modes of the present invention.

[0044] Figure 4This is a double-step wave target decomposition flow chart of a design method based on the FRB and MPDB high-speed collision modes of the present invention.

[0045] Figure 5 It is a vehicle front space grid diagram of a design method based on FRB and MPDB high-speed collision modes of the present invention.

[0046] Figure 6 It is a schematic diagram of the overlap of the vehicle body front end space grid and the vehicle body coordinate system according to a design method based on FRB and MPDB high-speed collision modes of the present invention.

[0047] Figure 7 It is a schematic diagram of the energy absorption space at the front end of a vehicle body according to a design method based on FRB and MPDB high-speed collision modes of the present invention. DETAILED DESCRIPTION

[0048] The following is based on the attached Figure 1-7 The present invention will be further described:

[0049] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0050] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0051] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0052] like Figure 1 As shown, the first embodiment of the present invention provides a design method based on the FRB and MPDB high-speed collision modes on the basis of the existing technology, including:

[0053] Step S10 , respectively obtaining the equivalent stiffness of the restraint system, the energy absorption space of the front end of the vehicle body, the topological structure of the front end of the vehicle body, the mass of the entire vehicle, and the mass and equivalent stiffness of the MPDB.

[0054] During the vehicle's conceptual design phase, the present invention calculates the equivalent stiffness of the restraint system, the front-end energy-absorbing space, the front-end topology, the vehicle mass, and the mass and equivalent stiffness of the MPDB. These values ​​are then calculated separately.

[0055] Step S20: The equivalent stiffness of the restraint system and the front energy absorption space of the vehicle body are used to obtain the FRB working condition occupant safety evaluation index by adopting the FRB analytical method. The specific steps are as follows:

[0056] Step S21, obtaining an equivalent double-step wave curve through the energy absorption space at the front end of the vehicle body, wherein:

[0057] The equivalent double-step wave curve uses the collision time as the horizontal axis and the vehicle acceleration as the vertical axis to simplify the vehicle collision acceleration time history into a double-step waveform. A is the initial moment of collision, that is, the moment when the bumper skin hits the rigid wall, T B T is the moment when the front crossbeam hits the rigid wall. C is the moment when the engine hits the rigid wall, T E T is the moment when the vehicle speed returns to zero. F is the moment when the vehicle collision acceleration returns to zero, such as Figure 2 The distance from the front end of the engine to the frontmost point of the front protective skin is D1, the distance from the rear end of the engine to the firewall is D2, and the distance from the front end of the engine to the front end of the energy absorption box is D3. Figure 3 shown.

[0058] Step S22: Using the equivalent double-step wave curve and the equivalent stiffness of the restraint system, an FRB analytical method is used to obtain an FRB operating condition occupant safety evaluation index, wherein:

[0059] Given the equivalent stiffness k of the constraint system and the double-step waveform curve a v (t), an iterative method is used to calculate the occupant safety evaluation index under FRB conditions, namely, the occupant chest acceleration peak a omax The vehicle displacement d can be obtained by integrating the double-step wave curve twice. v (t), the occupant acceleration calculated in each iteration is shown in the following formulas (1) and (2):

[0060]

[0061] a omax =max(ao ) (2)

[0062] where d o and d v are the displacements of the occupant and the vehicle, k is the equivalent stiffness of the restraint system, v o is the occupant velocity, a o is the occupant acceleration, z is the iteration number, ΔT is the time interval of each iteration, and the evaluation index of occupant safety is a omax .

[0063] In step S30, the energy absorption space of the front end of the vehicle body, the topological structure of the front end of the vehicle body, the mass of the whole vehicle, and the mass and equivalent stiffness of the MPDB are obtained by using the MPDB analysis method to obtain the vehicle compatibility evaluation index under the MPDB working condition; in step S31, the equivalent double-step wave curve and the topological structure of the front end of the vehicle body are obtained by using double-step wave target decomposition to obtain the energy absorption and deformation of the front end substructure of the vehicle body, wherein:

[0064] The double-step wave target decomposition is a process of gradually decomposing the defined double-step wave curve into the energy absorption and deformation of each front end substructure of the vehicle body in a certain order under the condition that the topological structure of the front end of the vehicle body is known. The specific steps are as follows, as shown in Figure 4 .

[0065] The deformation order and longitudinal deformation space of the substructure are determined. The deformation mechanism of the front end substructure is set according to the connection order (substructure in series or in parallel) of each substructure (including the bumper beam, the radiator, the energy absorption box, the front longitudinal beam, the front pointer beam, and the auxiliary frame), and the deformation order and longitudinal deformation space (X-axis of the vehicle body coordinate system) of the substructure are determined.

[0066] The YZ plane energy absorption space proportion of the substructure is determined. The vehicle body front end space grid is formulated as shown in Figure 5 . The Y-axis and Z-axis of the space grid are coincided with the Y-axis and Z-axis of the vehicle body coordinate system respectively under the condition that the front end structure of the vehicle body is known, as shown in Figure 6 . The number A of the grids occupied by the front end space of the vehicle body in the YZ plane is recorded, wherein the height of the front end space of the vehicle body is taken as the distance from the connecting line (upper edge) of the engine hood and the front windshield glass to the ground (lower edge), and the width is taken as the horizontal distance between the left and right outer edges (left and right edges) of the two front wheels of the vehicle, as shown in Figure 7As shown. The front space grid of the vehicle body is translated along the X-axis from the front to the rear of the vehicle, and the number of grids B passing through each substructure during the translation process is recorded. The energy absorption space ratio of the substructure is defined as α = B / A, which is used to represent the energy absorption space of the substructure relative to each vehicle in the YZ plane. The grid counting method is that if the occupied grid area is greater than or equal to 1 / 2, it is calculated as one grid, and if the occupied area is less than 1 / 2, the grid is not counted. The area of ​​each grid is 250mm×250mm=0.0625m 2 The product of the number of grids and the area of ​​each grid is the total area occupied by the structure or space.

[0067] When there is no actual front-end vehicle structure in the conceptual design phase, the above grid can be used to determine the energy absorption space proportion of the front-end substructure of the reference vehicle model in the YZ plane, or the energy absorption space proportion α of each substructure in the YZ plane can be directly given based on empirical values ​​for subsequent calculations.

[0068] The energy absorption ratio of the substructure is determined. When the front-end structure of the vehicle body is known, the finite element simulation technology is used to simulate the FRB collision condition of the vehicle. The energy absorption E1 of each substructure at the front end of the vehicle body and the total energy absorption E0 of all energy-absorbing structures at the front end of the vehicle body are extracted from the simulation calculation results. The energy absorption ratio of each substructure β=E1 / E0 is defined to represent the energy absorption effect of each substructure relative to all front-end structures. If the substructure of the front end of the vehicle body is unknown during the conceptual design stage, the substructure layout of the benchmark model can be referred to, and the finite element simulation results of the FRB collision condition of the benchmark model can be used to determine the energy absorption ratio of the substructure during the collision. If there is no benchmark model during the conceptual design stage, the energy absorption ratio β of each substructure can be directly given based on experience for subsequent calculations.

[0069] The double-step wave is decomposed according to the energy absorption ratio and longitudinal deformation space of the front terminal structure to obtain the energy absorption and deformation of the substructure. First, the double-step wave is segmented longitudinally according to the longitudinal deformation order of the substructure. Secondly, the amplitude of the double step is decomposed according to the number of substructures contained in each longitudinal space and the energy absorption ratio. If the double-step wave is divided into i segments longitudinally, and there are j substructures participating in the deformation energy absorption in the i-th segment, then the acceleration value a of the structure in the i-th segment deformation is ij As shown below:

[0070]

[0071] Among them, avi is the amplitude of the double step wave at the i-th segment, βij is the energy absorption ratio of the j-th front terminal structure, a ij The acceleration of the front terminal structure of the vehicle body is integrated with the product of the mass of the structure and the deformation, which is the energy absorption of the front terminal structure of the vehicle body.

[0072] The deformation of the front terminal structure of the vehicle body is obtained through the longitudinal deformation space.

[0073] In step S32, the energy absorption and deformation of the front terminal structure of the vehicle body, the mass of the vehicle, and the mass and equivalent stiffness of the MPDB are obtained by using the MPDB analytical method to obtain the MPDB working condition vehicle compatibility evaluation index, wherein:

[0074] The MPDB analytical method is a process that uses the vehicle mass, MPDB mass, and equivalent stiffness to iteratively calculate the MPDB vehicle compatibility evaluation indicators (MPDB occupant load index OLC value, maximum deformation MD, and deformation standard deviation SD) under given conditions of the front-end terminal structural deformation and energy absorption. The specific steps are as follows:

[0075] The equivalent stiffness between the vehicle and the barrier is obtained by the equivalent stiffness of the MPDB and the proportion of the energy absorption space of the substructure in the YZ plane. In the MPDB collision condition, the equivalent stiffness of the barrier is uniform in the YZ plane, while the equivalent stiffness of the front end structure of the vehicle body is non-uniform in the YZ plane. Therefore, the equivalent stiffness of the MPDB and the front end structure of the vehicle body is the result of the series and parallel connection of the stiffness of the two. If there are j substructures on the YZ plane corresponding to the i-th longitudinal space, then the equivalent stiffness K between the MPDB and the vehicle is eqi is the MPDB local stiffness K Bj and substructure equivalent stiffness K ij The result of connecting in series and then in parallel, where K Bj is the equivalent stiffness of the contact portion between the MPDB and the j-th structure, which is equal to the product of the equivalent stiffness KB of the entire MPDB and the energy absorption space ratio α of the j-th structure, as shown below:

[0076]

[0077] The relative displacement between the vehicle and the barrier is obtained by the equivalent stiffness between the vehicle and the barrier, the vehicle mass, and the mass of the MPDB. The MPDB and the vehicle are connected by the equivalent stiffness Keq to perform coordinated vibration. The solution of the vibration equation is as follows:

[0078]

[0079] Where, d B and d v are the displacements of the barrier and the vehicle, M eq is the equivalent mass, M B , M are the masses of the barrier and vehicle respectively, and f(t) is the equivalent mass M eq The vibration response, ω eqi is the natural frequency of the i-th segment of the system, and v0 is the collision velocity.

[0080] The MPDB working condition vehicle compatibility evaluation index is obtained through the relative displacement between the barrier and the vehicle, the equivalent stiffness between the vehicle and the barrier, and the equivalent double-step wave curve. The MPDB working condition vehicle compatibility evaluation index includes: the MPDB occupant load index, maximum deformation and deformation standard deviation.

[0081] In the vehicle MPDB collision condition, the vehicle compatibility evaluation index includes the MPDB occupant load index OLC, maximum deformation MD and deformation standard deviation SD. After obtaining the acceleration response of the vehicle and barrier in the MPDB condition, the velocity and displacement responses can be obtained by integrating them. The OLC value can be calculated based on the velocity curve of MPDB. The calculation process has a prescribed formula and is not described here. Based on the motion response of the vehicle and barrier, the three compatibility evaluation indicators of the MPDB collision condition are further derived. The relative motion displacement d of the vehicle and barrier is Bv for:

[0082] d Bv =d B +d v (9)

[0083]

[0084] Where: d Bv is the relative displacement between the barrier and the vehicle, d B is the displacement of the barrier, d v is the displacement of the vehicle, d Bij To decompose the deformation of each segment of the rear barrier, k ij is the vehicle stiffness of each part after decomposition, k Bij is the stiffness of the barrier after decomposition.

[0085] The calculation formula for the standard deviation SD of the barrier deformation is:

[0086]

[0087] Where m is the number of energy-absorbing subspaces in the front cabin. The maximum deformation MD of MPDB is:

[0088] MD=max(d Bij ) (12)

[0089] Step S40, using the FRB operating condition occupant safety evaluation index as the optimization target and the MPDB operating condition vehicle compatibility evaluation index as the constraint condition, obtains the optimal parameters of each vehicle front terminal structure to provide guidance for high-speed collision solution design. The specific contents are as follows:

[0090] Taking the parameters of the double-step wave curve as the first-level optimization variables, taking the passenger safety evaluation index (passenger acceleration peak value) of the FRB working condition as the optimization target, and taking the OLC value and the maximum deformation MD value of the MPDB working condition as the constraint conditions, first-level optimization is performed; keeping the double-step wave parameters after optimization unchanged, taking the energy absorption space ratio and the energy absorption ratio of the vehicle body front end structure as the second-level input, the maximum deformation MD and the deformation standard deviation SD values of the MPDB working condition are calculated, whether the two meet the requirements is judged, if they meet the requirements, the optimization is ended, if they do not meet the requirements, the second-level input needs to be modified, until the double-step wave curve parameters, the energy absorption space and the energy absorption ratio of the substructure meet the requirements, the double-step wave curve parameters, the energy absorption space and the energy absorption ratio of the substructure are the optimal parameters of each vehicle body front end substructure, and provide guidance for high-speed collision scheme design.

[0091] While embodiments of the application have been disclosed in connection with the above specification and drawings, it will be understood that it is not intended to limit the application to such details. There are many variations to the disclosed embodiments that fall within the scope of the application. Thus, those skilled in the art will readily appreciate that other modifications are encompassed by the application as defined by the claims and their equivalents.

Claims

1. A design method based on FRB and MPDB high-speed collision modes, characterized in that: include: Obtain the equivalent stiffness of the restraint system, the energy absorption space of the front end of the vehicle body, the topological structure of the front end of the vehicle body, the mass of the vehicle, and the mass and equivalent stiffness of the MPDB respectively; The equivalent stiffness of the restraint system and the energy absorption space at the front end of the vehicle body are obtained by adopting the FRB analytical method to obtain the FRB working condition occupant safety evaluation index; The MPDB working condition vehicle compatibility evaluation index is obtained by using the MPDB analytical method based on the front end energy absorption space of the vehicle body, the front end topology of the vehicle body, the vehicle mass, and the mass and equivalent stiffness of the MPDB; Using the FRB operating condition occupant safety evaluation index as the optimization target and the MPDB operating condition vehicle compatibility evaluation index as the constraint condition, the optimal parameters of each vehicle front substructure are obtained to provide guidance for high-speed collision solution design. The equivalent stiffness of the restraint system and the front energy absorption space of the vehicle body are used to obtain the FRB working condition occupant safety evaluation index by adopting the FRB analytical method, including: An equivalent double-step wave curve is obtained through the energy-absorbing space at the front end of the vehicle body; The FRB working condition occupant safety evaluation index is obtained by using the equivalent double-step wave curve and the equivalent stiffness of the restraint system using the FRB analytical method; The equivalent double-step wave curve includes: taking the collision time as the horizontal axis and the vehicle acceleration as the vertical axis, simplifying the vehicle collision acceleration time history into a double-step wave curve; The vehicle collision acceleration time history includes: the initial collision moment, the moment when the front bumper beam hits the rigid wall, the moment when the engine hits the rigid wall, the moment when the vehicle speed returns to zero, and the moment when the vehicle collision acceleration returns to zero; The FRB working condition occupant safety evaluation index is obtained by using the equivalent double-step wave curve and the equivalent stiffness of the restraint system using the FRB analytical method, including: The equivalent double-step wave curve and the equivalent stiffness of the restraint system are used to obtain the FRB operating condition occupant safety evaluation index according to formula (1) and formula (2): a omax =max(a o ) (2) Where: d o and d v are the displacements of the occupant and the vehicle respectively, k is the equivalent stiffness of the restraint system, v o is the passenger speed, a o is the occupant acceleration, z is the number of iterations, ΔT is the time interval between each iteration, and the evaluation index of occupant safety is a omax .

2. The design method based on FRB and MPDB high-speed collision modes according to claim 1, characterized in that: The MPDB working condition vehicle compatibility evaluation index is obtained by using the MPDB analytical method based on the front end energy absorption space of the vehicle body, the front end topology of the vehicle body, the vehicle mass, and the mass and equivalent stiffness of the MPDB, including: The equivalent double-step wave curve and the front-end topological structure of the vehicle body are decomposed by using the double-step wave target to obtain the energy absorption and deformation of the front-end terminal structure of the vehicle body; The energy absorption and deformation of the front terminal structure of the vehicle body, the mass of the vehicle, and the mass and equivalent stiffness of the MPDB are obtained by adopting the MPDB analytical method to obtain the MPDB working condition vehicle compatibility evaluation index.

3. The design method based on FRB and MPDB high-speed collision modes according to claim 2, characterized in that: The equivalent double-step wave curve and the front-end topology of the vehicle body are decomposed by using the double-step wave target to obtain the energy absorption and deformation of the front-end terminal structure of the vehicle body, including: The deformation sequence of the substructure, the longitudinal deformation space, the proportion of the substructure's energy absorption space in the YZ plane, and the energy absorption proportion of the front terminal structure are obtained through the front-end topological structure of the vehicle body; The energy absorption and deformation of the front terminal structure of the vehicle body are determined by the deformation sequence of the substructure, the longitudinal deformation space, the energy absorption ratio of the front terminal structure and the equivalent double-step wave curve.

4. The design method based on FRB and MPDB high-speed collision modes according to claim 3, characterized in that: The determining of the energy absorption and deformation of the front terminal structure of the vehicle body by using the longitudinal deformation space, the energy absorption ratio of the front terminal structure and the equivalent double-step wave curve includes: The double-step wave curve obtained by the deformation sequence of the equivalent double-step wave curve and the substructure is longitudinally segmented into i segments, and the energy absorption of the front terminal structure of the vehicle body is obtained by formula (3): Among them, a vi is the amplitude of the double-step wave in the i-th segment, β ij is the energy absorption ratio of the jth front terminal structure, a ij The acceleration of the front terminal structure of the vehicle body is integrated with the product of the mass of the structure and the deformation, which is the energy absorption of the front terminal structure of the vehicle body. The deformation amount of the vehicle body front terminal structure is obtained through the longitudinal deformation space.

5. The design method based on FRB and MPDB high-speed collision modes according to claim 4, characterized in that: The MPDB working condition vehicle compatibility evaluation index is obtained by using the MPDB analytical method based on the energy absorption and deformation of the front terminal structure of the vehicle body, the vehicle mass, and the mass and equivalent stiffness of the MPDB, including: The equivalent stiffness between the vehicle and the barrier is obtained by the equivalent stiffness of the MPDB and the proportion of the energy absorption space of the substructure in the YZ plane; The relative displacement between the barrier and the vehicle is obtained by the equivalent stiffness between the vehicle and the barrier, the vehicle mass, the acceleration of the front terminal structure of the vehicle body, and the mass of the MPDB; The MPDB working condition vehicle compatibility evaluation index is obtained through the relative displacement between the barrier and the vehicle, the equivalent stiffness between the vehicle and the barrier, and the equivalent double-step wave curve. The MPDB working condition vehicle compatibility evaluation index includes: the MPDB occupant load index, maximum deformation and deformation standard deviation.

6. The design method based on FRB and MPDB high-speed collision modes according to claim 5, characterized in that: The MPDB working condition vehicle compatibility evaluation index is obtained by the relative displacement between the barrier and the vehicle, the equivalent stiffness between the vehicle and the barrier, and the equivalent double-step wave curve, including: Obtaining the MPDB occupant load index through the equivalent double-step wave curve; The maximum deformation of the MPDB is obtained by the relative displacement between the barrier and the vehicle and the equivalent stiffness between the vehicle and the barrier; The deformation standard deviation of the MPDB is obtained by the maximum deformation of the MPDB.

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