A method, device and storage medium for determining the stiffness of a body in white

Abstract

The present application relates to a method, device and storage medium for determining the stiffness of a body-in-white, and relates to the technical field of vehicles. The steps of the method for determining the stiffness of the body-in-white are as follows: first, obtain the mass M of the test vehicle 试验 , according to the mass M 参照 and torsional stiffness K 参照 of the reference vehicle, and based on the relationship that the torsional stiffness of the vehicle is proportional to the mass, calculate the torsional stiffness K 试验 of the test vehicle. Then, establish a test mechanical model to obtain the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle, and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle. Finally, according to the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle, and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle, calculate the bending stiffness Y 试验 of the test vehicle. The method for determining the stiffness of the body-in-white provided by the present application solves the problems of long test cycle, high test cost, and consumption of a large amount of manpower and material resources when defining the stiffness of the body-in-white of the vehicle under development.

Description

Technical Field

[0001] The present application relates to the technical field of vehicles, and particularly relates to a method, device and storage medium for determining the stiffness of a white body in white (BIW). Background Art

[0002] The stiffness of the BIW is closely related to the fatigue durability, NVH (Noise, Vibration, Harshness) characteristics and handling stability of the vehicle. The stiffness of the BIW mainly includes torsional stiffness and bending stiffness. The target value of the BIW stiffness is derived from the requirements of the vehicle performance and guides the design of the BIW.

[0003] In the related art, for a vehicle model under development, in order to determine the target value of the BIW stiffness, a competing vehicle in the market is purchased, and after purchase, it is disassembled to obtain the BIW, and then the BIW stiffness test is carried out on a rigid test bench. Finally, the target value of the BIW stiffness of the vehicle model under development is defined by the test measurement value.

[0004] Although the current method can obtain the BIW stiffness more accurately, the whole process often requires spending a large amount of money to purchase competing vehicles in the market. After purchasing, it is also necessary to invest a lot of manpower and material resources to disassemble them one by one, which takes a long time. After disassembling into the BIW, relevant tests are carried out, and at the same time, the test cycle is also relatively long. The whole process will generate high test costs. Summary of the Invention

[0005] Embodiments of the present application provide a method, device and storage medium for determining the stiffness of a BIW, so as to solve the problems of long test cycle, high test cost and consumption of a large amount of manpower and material resources in the whole test process of defining the BIW stiffness of a vehicle model under development in the related art.

[0006] In a first aspect, the present application provides a method for determining the stiffness of a BIW, and its steps include:

[0007] Obtain the mass M of the test vehicle 试验 , and according to the mass M 参照 and torsional stiffness K 参照 of the reference vehicle, and based on the relationship that the torsional stiffness of the vehicle is proportional to the mass, calculate the torsional stiffness K 试验 of the test vehicle;

[0008] Establish a test mechanical model, and obtain the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle through the test mechanical model;

[0009] According to the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle, calculate the bending stiffness Y试验 。

[0010] In some embodiments, establishing the test mechanical model includes:

[0011] Equivalent the vehicle to a simply supported beam, and use the front axle and rear axle of the vehicle as two support points;

[0012] Wherein, the length of the simply supported beam is the overall vehicle length of the vehicle, and the distance between the two support seats is the wheelbase of the vehicle.

[0013] In some embodiments, obtaining the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle through the test mechanical model includes:

[0014] Apply a preset load vertically downward to the middle of the simply supported beam, and monitor the bending displacement of the middle of the simply supported beam under the action of the preset load;

[0015] Based on the relationship between the bending displacement and the relationship between the preset load and the bending stiffness of the vehicle, calculate the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle.

[0016] In some embodiments, obtaining the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle through the test mechanical model includes:

[0017] Monitor the vibration state when the simply supported beam bends, and determine the vibration type of the simply supported beam according to the vibration state;

[0018] Determine the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle according to the vibration type.

[0019] In some embodiments, calculating the bending stiffness Y of the test vehicle according to the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle 试验 , includes:

[0020] Calculate the relationship between the bending stiffness of the vehicle and the bending mode frequency according to the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle;

[0021] Obtain a relationship curve graph between the bending stiffness and the bending mode frequency of the vehicle according to the relationship between the bending stiffness and the bending mode frequency of the vehicle;

[0022] Calculate the bending stiffness Y of the test vehicle according to the vehicle parameters of the test vehicle and the relationship curve graph; 试验 。

[0023] Second aspect, the present application provides a white body stiffness determination device, which includes:

[0024] A torsional stiffness determination module, which is used to obtain the mass M of the test vehicle 试验 , and is used to calculate the torsional stiffness K of the test vehicle based on the mass M of the reference vehicle 参照 and the torsional stiffness K 参照 , based on the relationship that the torsional stiffness of the vehicle is proportional to the mass 试验 ;

[0025] A bending stiffness determination module, which is used to establish a test mechanical model, and is used to obtain the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle through the test mechanical model. The bending stiffness determination module is also used to calculate the bending stiffness Y of the test vehicle according to the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle 试验 .

[0026] In some embodiments, the bending stiffness determination module includes a modeling unit, which is used to equivalent the vehicle to a simply supported beam, and is used to use the front axle and the rear axle of the vehicle as two support points. Wherein, the length of the simply supported beam is the overall vehicle length of the vehicle, and the distance between the two support seats is the wheelbase of the vehicle.

[0027] In some embodiments, the bending stiffness determination module further includes an execution unit, which is used to apply a preset load vertically downward to the middle of the simply supported beam, and monitor the bending displacement amount of the middle of the simply supported beam under the action of the preset load. The execution unit is also used to monitor the vibration state when the simply supported beam bends, and determine the vibration type of the simply supported beam according to the vibration state.

[0028] In some embodiments, the bending stiffness determination module further includes an analysis module, which is used to calculate the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle based on the bending displacement amount based on the relationship between the preset load and the bending stiffness of the vehicle, and is also used to determine the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle according to the vibration type.

[0029] Third aspect, the present application provides a computer-readable storage medium, which includes a processor, and a computer program is stored on the processor. The feature is that: when the computer program is executed by the processor, the steps of the above-mentioned white body stiffness determination method are realized.

[0030] The beneficial effects brought by the technical solutions provided by the present application include:

[0031] An embodiment of the present application provides a method for determining the stiffness of a body-in-white. First, the mass M of a reference vehicle is obtained. 参照 and the torsional stiffness K 参照 . Based on the relationship that the torsional stiffness of a vehicle is proportional to its mass, according to the mass M of the test vehicle 试验 , the torsional stiffness K of the test vehicle can be calculated. 试验 Secondly, by establishing a test mechanical model, the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle, as well as the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle, are obtained. According to the above relationships and the vehicle parameters of the test vehicle, the bending stiffness Y of the test vehicle can be calculated. 试验 . This method for determining the stiffness of a body-in-white derives the target values of the torsional stiffness and bending stiffness of the body-in-white from the theoretical source based on the correlation between vehicle performances, establishes a method for quickly calculating the torsional stiffness and bending stiffness of the body-in-white, greatly saves the development cost of the body-in-white, and solves the problems of long test cycle, high test cost, and large consumption of manpower and material resources in the entire test process when defining the stiffness of the body-in-white of a vehicle under development in the related art. Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0033] Figure 1 It is a schematic flowchart of the method for determining the stiffness of a body-in-white provided by an embodiment of the present application.

[0034] Figure 2 It is a schematic flowchart of the method for determining the relationship between the bending stiffness of a vehicle and the material physical parameters of the vehicle provided by an embodiment of the present application.

[0035] Figure 3 It is a schematic diagram of the test mechanical model of the method for determining the stiffness of a body-in-white provided by an embodiment of the present application.

[0036] Figure 4 It is a curve graph of the relationship between the bending stiffness and bending mode frequency of a vehicle provided by an embodiment of the present application. Detailed Embodiments

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts shall fall within the scope of protection of this application.

[0038] The embodiment of this application provides a method for determining the stiffness of a white body in white (BIW), which can solve the problems of long test cycle, high test cost, and consumption of a large amount of manpower and material resources in the entire test process of defining the stiffness of the BIW of the vehicle under development in the related art.

[0039] See Figure 1 As shown, the steps of this method for determining the stiffness of the BIW mainly include first obtaining the mass M of the test vehicle 试验 , and based on the mass M 参照 and torsional stiffness K 参照 of the reference vehicle, and based on the relationship that the torsional stiffness of the vehicle is proportional to the mass, calculating the torsional stiffness K 试验 of the test vehicle; then establishing a test mechanical model, obtaining the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle through the test mechanical model, and then calculating the bending stiffness Y 试验 of the test vehicle according to the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle.

[0040] Specifically, the torsional stiffness of the BIW is closely related to the fatigue durability performance of the whole vehicle. For a load-bearing BIW, the failure form is mainly torsional fatigue. When the torsional stiffness is insufficient, the body undergoes large torsional deformation under the action of external forces, and local weak points may be fatigued and damaged after repeated loading. At the same time, when the torsional stiffness of the body is insufficient, it may cause friction and abnormal noise between components. The fatigue condition of the BIW body belongs to the category of low-load high-cycle fatigue. Regarding the whole body as a whole, under the same conditions of road load, tire stiffness, suspension geometry, and KC (Kinematic, Compliance), the magnitude of the road excitation force received by different models on the same platform is proportional to the full-load mass of the whole vehicle.

[0041] Specifically, the relationship between the fatigue life of the vehicle and the stress magnitude can be expressed by the following power function formula according to the low-load high-cycle section of the typical S-N curve:

[0042] S α N = C Formula 1

[0043] Among them, S in Formula 1 is stress, N is fatigue life, and both α and C are material constants.

[0044] Specifically, the torsional deformation of the vehicle road surface under load is simplified to a circular shaft torsion model. The magnitude of the stress S on the circular shaft is proportional to the torque T and inversely proportional to the torsional stiffness K. The following relationship between stress S, torque T, and torsional stiffness K is obtained:

[0045]

[0046] For torsion T, the torque T received by different vehicle models on the same platform is proportional to the full-load mass M of the whole vehicle. Therefore, the following relational expression between stress S, full-load mass M of the whole vehicle, and torsional stiffness K is obtained:

[0047] T = C1M Formula 3

[0048]

[0049] Among them, C1 in Formula 3 is a constant. Combining Formula 3 and Formula 4, it is obtained that stress S is proportional to the full-load mass M of the whole vehicle and inversely proportional to the torsional stiffness K.

[0050] Specifically, from Formula 4 and Formula 1, the following expression is obtained:

[0051]

[0052] Among them, α in Formula 5 is a material constant, and the material parameters of general vehicle steel plates are 4 - 6.

[0053] Specifically, in practical applications, a certain sedan on the same platform is extended to an SUV model. The underbody and its chassis of the vehicle basically remain unchanged, only the upper body of the vehicle is changed while ensuring that the SUV has the same reliable durability as the sedan. When formulating the torsional stiffness target of the white body of the SUV model, based on the torsional stiffness of the white body of the sedan, the torsional stiffness of the white body of the new SUV model is obtained. Here, the sedan is the reference vehicle, and its mass and torsional stiffness are both known parameters. Since it can be deduced from the previous Formulas 1 to 5 that under the condition of equal fatigue life N, the relationship between the torsional stiffness and the vehicle mass of different vehicle models on the same platform is a proportional relationship, as shown in the following expression:

[0054]

[0055] According to Formula 6, the calculation example of the torsional stiffness of the test vehicle is as follows: For example, the full-load mass M of test vehicle A 试验 is 2100 kg, and the full-load mass M of the reference vehicle B already on the market on the same platform 参照 is 1800 kg, and the torsional stiffness K 参照If it is 12000 Nm / Deg, then according to Formula 6, the torsional stiffness K of the body-in-white of the vehicle under development, Test Vehicle A, can be obtained. 试验 should be greater than 14000 Nm / Deg. Among them, M 试验 i.e., M in Formula 6 SUV , K 试验 i.e., K in Formula 6 SUV , M 参照 i.e., M in Formula 6 轿车 , K 参照 i.e., K in Formula 6 轿车 .

[0056] Specifically, the bending stiffness of the body-in-white is closely related to the bending modal performance of the whole vehicle. During the R & D process of the vehicle, there are clear requirements for the first-order bending mode of the whole vehicle. Here, based on the first-order bending mode value of the whole vehicle, the bending stiffness of the body-in-white is obtained through model equivalence and formula derivation. When the vehicle is driving on the road surface, it is mainly supported by the front and rear tires. Referring to Figure 3 as shown, the specific steps to establish the test mechanical model include first equivalenting the vehicle to a simply supported beam, and taking the front axle and rear axle of the vehicle as two support points. Among them, the length of the simply supported beam is the overall vehicle length L of the vehicle, and the distance between the two support seats is the wheelbase t of the vehicle.

[0057] Furthermore, referring to Figure 2 as shown, the steps to obtain the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle through the test mechanical model specifically include: First, apply a preset load vertically downward to the middle of the simply supported beam, and monitor the bending displacement of the middle of the simply supported beam under the action of the preset load; Then, based on the relationship between the bending displacement and the preset load and the bending stiffness of the vehicle, calculate the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle, which is specifically as follows:

[0058]

[0059] Among them, in Formula 7, Y is the bending stiffness, F is the applied preset load force, d is the bending displacement of the middle of the simply supported beam under the action of the preset load, E is the elastic modulus, I is the section moment of inertia, t is the wheelbase of the whole vehicle, and L is the overall vehicle length.

[0060] Furthermore, the specific steps to obtain the relationship between the bending modal frequency of the vehicle and the material physical parameters of the vehicle through the test mechanical model include: First, monitor the vibration state when the simply supported beam bends, and determine the vibration type of the simply supported beam according to the vibration state; Then, determine the relationship between the bending modal frequency of the vehicle and the material physical parameters of the vehicle according to the vibration type. The first-order bending modal frequency of the simply supported beam can be specifically expressed as follows according to the vibration mode:

[0061]

[0062] Among them, f is the bending mode frequency, and M1 is the total mass rigidly connected to the body-in-white, which is about 0.6 times the curb weight M of the whole vehicle.

[0063] Furthermore, according to the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle, the bending stiffness Y of the test vehicle is calculated. 试验 The steps include: First, according to the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle, calculate the relationship between the bending stiffness and the bending mode frequency of the vehicle. Then, obtain the relationship curve graph between the bending stiffness and the bending mode frequency of the vehicle according to the relationship between the bending stiffness and the bending mode frequency of the vehicle. Finally, calculate the bending stiffness Y of the test vehicle according to the vehicle parameters of the test vehicle and the relationship curve graph. 试验 .

[0064] Specifically, substituting Equation 7 into Equation 8 gives the relationship between the bending stiffness Y and the bending mode frequency f as follows:

[0065]

[0066] When the mass is constant, the relationship curve graph between the bending stiffness Y and the bending mode frequency f is shown in Figure 4 .

[0067] According to Figure 4 the relationship curve graph between the bending stiffness Y and the bending mode frequency f shown in and Equation 9, the bending stiffness Y of the test vehicle 试验 The calculation example is as follows: Since the bending stiffness of the vehicle is quadratic with the bending mode frequency, the bending stiffness of the body-in-white can be obtained according to the requirements of the first-order bending mode of the whole vehicle. For example, the overall length of the test vehicle A is 4500 mm, the wheelbase is 2600 mm, the total mass of the body-in-white and the mass rigidly connected to the body-in-white is 900 kg, and the requirement of the first-order bending mode of the whole vehicle is greater than 30 Hz. Then, according to Equation 9, it is inversely calculated that the bending stiffness of the body-in-white of the test vehicle should be greater than 15860 N / mm, where Y 试验 is the Y corresponding to Equation 9.

[0068] This method for determining the stiffness of the body-in-white derives the target values of the torsional stiffness and bending stiffness of the body-in-white from the theoretical source according to the correlation between vehicle performances, establishes a method for quickly calculating the torsional stiffness and bending stiffness of the body-in-white, greatly saves the development cost of the body-in-white, and solves the problems of long test cycle, high test cost, and large consumption of manpower and material resources in the whole test process when defining the stiffness of the body-in-white of the vehicle under research in the related technology.

[0069] The present application also provides a white body stiffness determination device, which mainly includes a torsional stiffness determination module and a bending stiffness determination module. Among them, the torsional stiffness determination module is used to obtain the mass M of the test vehicle 试验 , and is used to calculate the torsional stiffness K of the test vehicle based on the mass M of the reference vehicle 参照 and the torsional stiffness K 参照 of the vehicle, based on the relationship that the torsional stiffness of the vehicle is proportional to the mass 试验 ; the bending stiffness determination module is used to establish a test mechanical model, and is used to obtain the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle through the test mechanical model. The bending stiffness determination module is also used to calculate the bending stiffness Y of the test vehicle according to the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle 试验 .

[0070] Further, the bending stiffness determination module includes a modeling unit, which is used to equivalent the vehicle to a simply supported beam, and is used to take the front axle and the rear axle of the vehicle as two support points. Among them, the length of the simply supported beam is the overall vehicle length of the vehicle, and the distance between the two support seats is the wheelbase of the vehicle

[0071] Further, the bending stiffness determination module also includes an execution unit, which is used to apply a preset load vertically downward to the middle part of the simply supported beam, and monitor the bending displacement of the middle part of the simply supported beam under the action of the preset load. The execution unit is also used to monitor the vibration state when the simply supported beam bends, and determine the vibration type of the simply supported beam according to the vibration state

[0072] Further, the bending stiffness determination module also includes an analysis module, which is used to calculate the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle based on the bending displacement according to the relationship between the preset load and the bending stiffness of the vehicle, and is also used to determine the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle according to the vibration type

[0073] Among them, the function realization of each module in the above white body stiffness determination device corresponds to each step in the above white body stiffness determination method, and its function and realization process will not be elaborated here one by one

[0074] The present application also provides a computer-readable storage medium, which includes a processor, and a computer program is stored on the processor. When the computer program is executed by the processor, the steps of the above white body stiffness determination method can be realized

[0075] Among them, the method realized when the computer program is executed can refer to each step of the above white body stiffness determination method, and will not be elaborated here

[0076] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application. Unless otherwise clearly specified and defined, the terms "installed", "connected" and "coupled" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0077] It should be noted that in the present application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0078] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for determining the stiffness of a white body, characterized in that, The steps include: Obtain the mass M of the test vehicle 试验 , according to the mass M of the reference vehicle 参照 and the torsional stiffness K 参照 , and based on the relationship that the torsional stiffness of the vehicle is proportional to the mass, calculate the torsional stiffness K of the test vehicle 试验 ; Establish a test mechanical model, and obtain the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle, as well as the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle through the test mechanical model; Based on the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle, as well as the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle, the bending stiffness Y of the test vehicle is calculated 试验 ; Obtaining the mass M of the test vehicle 试验 , according to the mass M 参照 and torsional stiffness K 参照 of the reference vehicle, and based on the relationship that the torsional stiffness of the vehicle is proportional to the mass, calculating the torsional stiffness K of the test vehicle 试验 The specific steps are as follows: Regarding the entire vehicle body as a whole, under the conditions of the same road surface load, tire stiffness, suspension geometry, and KC, the relationship between the fatigue life of the vehicle and the stress magnitude, according to the low-cycle high-cycle section of the typical S-N curve, is expressed by formula (1): Formula (1); Wherein, S is the stress, N is the fatigue life, and both α and C are material constants; Simplify the torsional deformation of the vehicle under road load into a circular shaft torsion model. The magnitude of the stress S on the circular shaft is proportional to the torque T and inversely proportional to the torsional stiffness K, and the following relationship between the stress S, the torque T, and the torsional stiffness K is obtained: Formula (2); For the torsion T, the torque T received by different vehicle models on the same platform is proportional to the full-load mass M of the whole vehicle, and the following relational formula between the stress S, the full-load mass M of the whole vehicle, and the torsional stiffness K is obtained: Formula (3); Formula (4); Wherein, C1 is a constant; Combining formula (4) and formula (1) to obtain formula (5): Formula (5); Wherein, α is a material constant; When the fatigue life N is equal, the relationship between the torsional stiffness and the vehicle mass of different vehicle models on the same platform is a proportional relationship.

2. The method for determining the stiffness of a white body according to claim 1, wherein The establishing of the test mechanical model includes: Equivalent the vehicle to a simply supported beam, and use the front axle and the rear axle of the vehicle as two support points; Wherein, the length of the simply supported beam is the overall vehicle length of the vehicle, and the distance between the two support points is the wheelbase of the vehicle.

3. The method for determining the stiffness of a white body as described in claim 2, characterized in that The obtaining of the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle through the test mechanical model includes: Apply a preset load vertically downward to the middle part of the simply supported beam, and monitor the bending displacement of the middle part of the simply supported beam under the action of the preset load; Based on the relationship between the bending displacement and the preset load and the bending stiffness of the vehicle, calculate to obtain the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle.

4. The method for determining the stiffness of a white body according to claim 3, characterized in that, The obtaining of the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle through the test mechanical model includes: Monitor the vibration state when the simply supported beam bends, and determine the vibration type of the simply supported beam according to the vibration state; Determine the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle according to the vibration type.

5. The method for determining the stiffness of a white body according to claim 4, characterized in that Calculating the bending stiffness Y of the test vehicle according to the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle 试验 , including: Calculate the relationship between the bending stiffness and the bending mode frequency of the vehicle according to the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle; Obtain a relationship curve graph between the bending stiffness and the bending mode frequency of the vehicle according to the relationship between the bending stiffness and the bending mode frequency of the vehicle; The bending stiffness Y of the test vehicle is calculated based on the vehicle parameters of the test vehicle and the relationship curve graph 试验 .

6. A white body stiffness determination device using the white body stiffness determination method described in claim 1, characterized in that, It includes: A torsional stiffness determination module, which is configured to obtain the mass M of the test vehicle 试验 , and is configured to calculate the torsional stiffness K of the test vehicle based on the mass M 参照 of the reference vehicle and the torsional stiffness K 参照 , based on the relationship that the torsional stiffness of a vehicle is proportional to its mass 试验 ; A bending stiffness determination module, which is used to establish a test mechanical model and to obtain the relationship between the bending stiffness of a vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle through the test mechanical model. The bending stiffness determination module is further used to calculate the bending stiffness Y of the test vehicle according to the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle and the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle 试验 。 7. The white body stiffness determination device according to claim 6, characterized in that: The bending stiffness determination module includes a modeling unit, and the modeling unit is used to equivalent the vehicle to a simply supported beam and is used to use the front axle and the rear axle of the vehicle as two support points. Wherein, the length of the simply supported beam is the overall vehicle length of the vehicle, and the distance between the two support points is the wheelbase of the vehicle.

8. The white body stiffness determination device according to claim 7, characterized in that: The bending stiffness determination module further includes an execution unit, which is configured to apply a preset load vertically downward to the middle of the simply supported beam, and monitor the bending displacement of the middle of the simply supported beam under the action of the preset load. The execution unit is further configured to monitor the vibration state of the simply supported beam during bending, and determine the vibration type of the simply supported beam according to the vibration state.

9. The white body stiffness determination device according to claim 8, characterized in that: The bending stiffness determination module further includes an analysis module, which is configured to calculate the relationship between the bending stiffness of the vehicle and the material physical parameters of the vehicle based on the relationship between the preset load and the bending stiffness of the vehicle according to the bending displacement, and is further configured to determine the relationship between the bending mode frequency of the vehicle and the material physical parameters of the vehicle according to the vibration type.

10. A computer-readable storage medium, which includes a processor, and a computer program is stored on the processor, characterized in that: When the computer program is executed by the processor, the steps of the white body stiffness determination method according to any one of claims 1 to 5 are implemented.

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