CN114818118A

CN114818118A - Air spring system structural member design method, device, equipment and storage medium

Info

Publication number: CN114818118A
Application number: CN202210347244.1A
Authority: CN
Inventors: 武小一; 李刚; 佟凯旋; 李耀超; 朱学武
Original assignee: FAW Group Corp
Current assignee: FAW Group Corp
Priority date: 2022-04-01
Filing date: 2022-04-01
Publication date: 2022-07-29

Abstract

The invention belongs to the technical field of automobiles, and particularly relates to a method, a device, equipment and a storage medium for designing a structural member of an air spring system. The method comprises the following steps: firstly, establishing a high-precision air spring axisymmetric finite element model; secondly, establishing a high-precision air spring entity finite element model; thirdly, modeling and simulation analysis of the air suspension are carried out; fourthly, simulation analysis of structural part strength; fifthly, checking and optimizing the strength of the structural part. The invention adopts a flexible body auxiliary method modeling and fluid-solid coupling solving combination method to analyze the structural strength, and each increment step of simulation analysis adjusts the contact state and the structural rigidity according to the analysis result to correctly describe the large deformation mechanical behavior of the flexible structure under the loading of the structure. Errors caused by the type and the connection position of the connection unit in finite element modeling are avoided, and the simulation precision is ensured; and system analysis is adopted to replace single piece analysis, so that the assembly clearance and contact relation change under the loaded condition can be correctly reflected, and the structural simulation precision is improved.

Description

Air spring system structural member design method, device, equipment and storage medium

Technical Field

The invention belongs to the technical field of automobiles, and particularly relates to a method, a device, equipment and a storage medium for designing a structural member of an air spring system.

Background

Air springs tend to be popular in high-end passenger vehicles due to their good stiffness characteristics, but compared to conventional suspensions in the form of coil springs, air springs generally provide greater axial loads, and thus structural member loading conditions on the spring channels are more severe. The spring channel mainly comprises a control arm, a vehicle body, an upper cover, a lower cover and other structural parts of the hollow spring, wherein the structural parts of the hollow spring are mainly made of non-metallic materials, the strength of the materials is low, and structural strength checking is necessary.

The method comprises the steps of firstly, determining the load condition of structural part strength checking, generally adopting suspension load decomposition to extract air spring load conditions, generally defining the axial stiffness and the buckling stiffness of the air spring based on a stiffness curve, but the buckling stiffness of the air spring is related to multiple factors such as air pressure and length, and the stiffness curve cannot represent the actual buckling stiffness of the air spring, so that the air spring strength analysis condition obtained through load decomposition cannot support high-precision strength analysis.

The second method for obtaining the strength check load condition of the structural part is to obtain the displacement of the air spring under the specified working condition or posture based on the suspension DMU analysis, and use the displacement as the input condition of the air spring system analysis, or extract the load of the corresponding air spring based on the displacement of the air spring as the input condition. However, structural member deformation and suspension bushing hard point displacement are not considered in DMU analysis, and the spring displacement direction is not fixed and does not follow the axial direction, so that the air spring obtained by the method has inaccurate analysis displacement and load conditions, and cannot support high-precision strength check.

And the second step is to check the structural strength, the check of the structural strength based on a finite element means is an industry universal means, a load point in the model is connected with the structural member through a rigid unit, and the load is transmitted to the structural member through the rigid unit. In actual working conditions, the air spring upper cover and the air spring lower cover are both in contact with the air spring capsule skin, the contact surface of the capsule skin and a structural part changes under the load condition, and the axial symmetry is not kept. Therefore, the analysis precision cannot be ensured by adopting a finite element model of the common rigid connection unit, and the connection unit for changing the connection position or the adaptive rigidity in real time is lacked in the general software, so that the high-precision structural member stress analysis cannot be realized.

In conclusion, the following conclusions are drawn: the air spring structural part analysis based on the traditional analysis method mainly has two problems: 1. the load precision of the structural part is insufficient; 2. the accuracy of the structural member strength analysis model is insufficient. Therefore, the stress analysis precision of the air spring structural member of the passenger car cannot support the strength design, and a new simulation method needs to be developed to improve the analysis precision.

Disclosure of Invention

The invention provides a method, a device, equipment and a storage medium for designing an air spring system structural member based on a flexible body auxiliary method. Errors caused by the types and the connection positions of the connection units in finite element modeling are avoided, and the simulation precision is ensured; and system analysis is adopted to replace single piece analysis, so that the assembly clearance and contact relation change under the loaded condition can be correctly reflected, and the structural simulation precision is improved.

The technical scheme of the invention is described as follows by combining the attached drawings:

in a first aspect, an embodiment of the present invention provides a method for designing a structural member of an air spring system, including the following steps:

step one, establishing a high-precision air spring axisymmetric finite element model;

step two, establishing a high-precision air spring entity finite element model based on the high-precision air spring axisymmetric finite element model established in the step one;

step three, guiding the high-precision air spring solid finite element model established in the step two into a suspension system for air suspension modeling and simulation analysis;

fourthly, simulation analysis of structural part strength;

and fifthly, checking and optimizing the strength of the structural part.

Further, the specific method of the first step is as follows:

11) establishing an air spring axial symmetry analysis model;

dividing the air spring model grid based on any symmetrical surface of the air spring, and defining rigid body attributes and rigid body reference points of an upper cover, a lower cover and a snap ring of the air spring; defining contact surfaces and contact relations of a rigid body and an elastic body in the air spring model; dividing the capsule body unit and the reinforcing cord line unit, defining the reinforcing rib attribute of the cord line unit, and establishing an air spring axisymmetric finite element model;

12) establishing an auxiliary flexible body;

defining the properties of the super-elastic material and the flexible body, and associating the empty reed capsule skin part with the properties of the super-elastic material and the flexible body; defining a fluid-solid coupling interface based on the bag body grid and the partial structure grid, serving as an action surface of air and a structure, and defining fluid-solid coupling properties of the interface; defining an outer surface contact surface of the flexible body structure and defining a contact pair associated therewith;

13) defining a simulation working condition;

setting boundary conditions of axial symmetry air spring model simulation, and defining a load step: the air spring is inflated to a design target value P0, and the air spring axially displaces load [ -U1, U1] along the direction of the symmetry axis;

14) solving a finite element model;

solving an axial symmetry simplified analysis model of the air spring, extracting the support reaction force F0 of the air spring along the direction of the symmetry axis, extracting the relation between the support reaction force and the axial displacement, generating an F-U curve, extracting the support reaction force under the specified displacement condition, and obtaining the rigidity of the specified displacement through post-processing;

15) judging the simulation precision;

selecting a plurality of points on the F-U curve according to the displacement condition, and calculating the air spring support reaction difference delta F according to the formula (1) _i ' difference value delta K between air spring stiffness and " _i ：

In the formula, Fd _i Is the axial force on the design target curve; kd _i Is the axial force and stiffness on the design target curve; f _i ' is the axial force difference of the air spring simulation curve under the corresponding load condition; k' _i The rigidity difference of the air spring simulation curve under the corresponding load condition is shown.

a) If the following conditions are satisfied:

judging that the simulation air spring axisymmetric model meets the requirement of simulation precision;

b) if the condition specified by the formula (2) is not met, judging that the air spring simulation precision does not meet the standard, repeating the processes of the steps 11) -13), redefining the materials, the attributes and the contact conditions until the precision specified by the formula (2) is achieved, and judging that the air spring axisymmetric model meets the simulation precision requirement.

Further, the specific method of the second step is as follows:

21) generating a solid finite element grid; rotating the air spring axisymmetric finite element model established in the step one around a symmetric axis to generate an air spring grid of a solid unit, and deleting the original axisymmetric grid;

22) defining an auxiliary flexible body; defining the flexible body attribute of the capsule skin grid in the solid model and associating with the super elastic material;

23) updating the model parameters; updating the attribute of a deformation body of the structural 3D unit and the attribute of a reinforcing rib of the plane cord line unit, redefining the attribute of a structural rigid body based on the 3D unit, and updating the contact surface of the air spring part;

24) updating the coupling action area; redefining a closed fluid and solid interface area, wherein the closed fluid and solid interface area comprises part of inner surfaces of the capsule skin, the upper cover and the lower cover and is used as an interaction surface between air and the structure; redefining the contact surface of the outer surface of the capsule shell, and keeping the mutual contact relationship between the hollow spring structures unchanged;

25) updating the boundary and the load condition; defining the integral boundary conditions in all the freedom directions, the boundary conditions in the inflation load step and the boundary conditions in the axial displacement load step;

26) solving a finite element model; solving an air spring entity analysis model, extracting the relation between the support reaction force of the air spring along the direction of the symmetry axis and the axial displacement to generate an F-U curve, extracting the support reaction force under the specified displacement load condition, and solving the stiffness value of the air spring under the specified displacement load condition;

27) judging the simulation precision; based on the air spring support reaction force and the stiffness value obtained in the step 26), a support reaction force difference value and a stiffness difference value are calculated according to the formula (1)

In the formula,. DELTA.F _i "is the difference value of the support reaction force of the air spring; delta K' _i Is the air spring stiffness difference: fd _i Is the axial force on the design target curve; kd _i Is the axial force and stiffness on the design target curve; f _i ' is the axial force difference of the air spring simulation curve under the corresponding load condition; k' _i The rigidity difference of the air spring simulation curve under the corresponding load condition is obtained;

a) if the support reaction difference value and the rigidity difference value meet the condition of the formula (2), judging that the air spring entity finite element model meets the requirement of simulation precision;

b) if the support reaction difference value and the rigidity difference value do not satisfy the condition of the formula (2), judging that the air spring solid finite element model does not satisfy the simulation precision requirement, repeating the processes of the steps 21) to 27), redefining the grid size, the contact and the boundary conditions until the precision specified by the formula (2) is achieved, and judging that the air spring solid finite element model satisfies the simulation precision requirement;

further, the specific method of the third step is as follows:

31) importing a solid model; selecting a suspension model under a specified posture, and importing the suspension model into the high-precision air spring entity finite element model in the step two;

32) correcting the attitude of the air spring model; the method comprises the following steps of (1) enabling a reference point of a rigid body structure of a lower cover of the air spring to be superposed with a lower point of the spring, measuring an included angle formed by an upper point of the spring, the lower point of the spring and a reference point of a rigid body of an upper cover, and rotating an air spring model on a plane formed by the three points according to the measured angle to ensure that the axis of an air spring entity model containing an auxiliary flexible body is consistent with the design axis of the spring;

33) correcting the position of the air spring model; moving the hollow spring along the axial direction of the spring until the lower cover of the spring is superposed with the design position, and then, the upper cover is also positioned at the design position;

34) adjusting an air spring model; modifying the rigid body definition in the air spring finite element model, updating the lower point of the spring to be a rigid body reference point of the lower cover, and updating the upper point of the spring to be a rigid body reference point of the upper cover;

35) loading the air suspension, namely, loading the air suspension by 2 load steps according to the following process;

351) defining an air spring inflation loading step; restraining 1-6 degrees of freedom of the upper point of the air spring, the upper point of the shock absorber, the connection point of the auxiliary frame and the vehicle body, restraining the vertical degree of freedom of the wheel center, inflating the air spring to a specified attitude pressure target P0, and extracting the vertical support reaction force Fzw0 of the wheel center at the moment;

352) defining a suspension displacement load step; removing vertical constraint at the wheel center position, applying a vertical displacement load Uzw, extracting a vertical support reaction force Fzw of the wheel center, a lower point displacement Uj of a shock absorber, an upper point support reaction force Fj of the shock absorber, a displacement Us of a lower point of an air spring, a support reaction force Fs of an upper point of the air spring and a support reaction moment Ms, and generating a wheel center vertical load-displacement curve, namely an Uzw-Fzw curve, a shock absorber load curve, namely an Uzw-Fj curve, and an air spring load curve, namely an Uzw-Fs curve;

36) judging the simulation progress; the simulation precision is judged by comparing the air suspension system test and the system simulation result, and the method comprises the following steps:

361) taking a plurality of points on the wheel center vertical load-displacement curve according to the displacement condition, and calculating the difference value of the wheel center load simulation and the test according to the formula (3):

△Fzw _i ＝|Fzw _i -Fzw' _i | (3)

in the formula, Fzw _i Is a simulated value of the vertical load of the wheel center; fzw' _i Is a test value of the wheel center vertical load; delta Fzw _i Is the difference between the wheel center vertical load simulation and the test;

a) if the following conditions are satisfied:

△Fzw _i ≤0.01*Fzw' _i (4)

judging that the simulation precision of the wheel center vertical load meets the requirement, and turning to step 362);

b) if the condition specified by the formula (4) is not met, judging that the simulation precision of the wheel center vertical load does not meet the requirement, repeating the operations from the step 31) to the step 35), and adjusting the rigidity property of the elastic connection unit in the model until the formula (4) is met; at this time, judging that the simulation precision of the vertical load of the wheel center of the air suspension model meets the requirement, and turning to step 362);

362) respectively taking a plurality of points on a shock absorber load curve and an air spring load curve, and respectively calculating the difference value between the shock absorber and the spring load test and the simulation according to the formula (5):

in the formula, Fj _i And Fs _i Are simulated values of shock absorber and spring load, respectively; fj' _i And Fs' _i Test values for shock absorber and spring load, respectively; delta Fj _i The sum delta Fs is the difference value of the simulation and the test of the shock absorber and the spring load respectively;

a) if the following conditions are satisfied:

judging that the simulation precision of the air suspension meets the requirement;

b) if the condition specified by the formula (6) is not met, the distribution of the vertical load in the spring and the shock absorber channel is judged not to be in accordance with the reality, the simulation precision of the air suspension does not meet the requirement, the operations from the step 31) to the step 35) are repeated, the stiffness curve of the shock absorber channel in the model is mainly adjusted until the formula (6) is met, and at the moment, the air suspension model is judged to meet the simulation precision requirement.

Further, the specific method of the fourth step is as follows:

41) model replacement; dividing grids based on a geometric model of a structural member of the air spring system, introducing the grids into an air suspension model, adjusting the position and the posture of the air suspension model, and keeping the grids of the auxiliary flexible body unchanged;

42) deleting the rigid body; deleting rigid body models and reference points which are not involved in the structural member strength simulation analysis model;

43) introducing an auxiliary analysis structure; introducing structural grids necessary for strength analysis of the air spring system structural member into an air suspension model except for an analysis object;

44) defining a contact; defining contact surfaces for the models introduced in steps 41) and 43), and all contact pairs involved by the contact surfaces;

45) material and attribute definition; introducing a model aiming at the step 41) and the step 43), defining actual material characteristics, and defining attributes according to the structure and grid characteristics;

46) solving the model; loading, wherein the loading process comprises the following steps:

461) defining an air spring inflation loading step; restraining 1-6 degrees of freedom of the upper point of the air spring, the upper point of the shock absorber, the connection point of the auxiliary frame and the vehicle body, restraining the vertical degree of freedom of the wheel center, inflating the air spring to a specified attitude pressure target P0, and extracting the vertical support reaction force Fzw0 of the wheel center at the moment;

462) defining a suspension displacement load step; removing vertical constraint at the wheel center position, applying a vertical displacement load Uzw, extracting a vertical support reaction force Fzw of the wheel center, a lower point displacement Uj of a shock absorber, an upper point support reaction force Fj of the shock absorber, a displacement Us of a lower point of an air spring, a support reaction force Fs of an upper point of the air spring and a support reaction moment Ms, and generating a wheel center vertical load-displacement curve, namely an Uzw-Fzw curve, a shock absorber load curve, namely an Uzw-Fj curve, and an air spring load curve, namely an Uzw-Fs curve;

and the suspension displacement is defined as the vertical rebound stroke limit of the wheel center, and the stress field S of the second load step structural member is extracted after the strength analysis model is solved.

Further, the specific method of the fifth step is as follows:

51) checking the strength; the structural strength is checked as specified by equation (7):

n＝σ _max /[σ] (7)

in the formula, σ _max Is the maximum stress value in the stress field S of the structural member; [ sigma ]]Is the allowable stress of the structural member; n is a safety coefficient of the air spring structural member under the limit use condition;

a) if the following conditions are satisfied:

n>1 (8)

judging that the structural part meets the strength design requirement, and ending the process;

b) if the condition specified by the formula (8) is not met, judging that the strength of the air spring structural member does not meet the design requirement, and turning to the step 52);

52) performing structural optimization iteration; and (5) carrying out structural optimization on the structural member, and repeating the operations from the step 41) to the step 51) for the optimized structure until the requirement of the formula (8) is met, and finishing the design.

In a second aspect, an embodiment of the present invention further provides an apparatus for designing a structural member of an air spring system, including:

the first modeling module is used for establishing a high-precision air spring axisymmetric finite element model;

the second modeling module is used for establishing a high-precision air spring entity finite element model;

the modeling and simulation analysis module is used for guiding the high-precision air spring entity finite element model into a suspension system for modeling and simulation analysis of the air suspension;

the strength simulation analysis module is used for carrying out simulation analysis on the structural member in the air spring system;

and the strength checking and optimizing module is used for checking structural members in the air spring system and designing the structural members with high strength.

Further, the first modeling module includes:

establishing an air spring axial symmetry analysis model module for establishing an air spring axial symmetry analysis model;

an auxiliary flexible body model building module is used for building an auxiliary flexible body model;

the simulation condition defining module is used for defining simulation conditions;

the first finite element model solving module is used for solving an air spring axisymmetric simplified typing model;

the simulation precision judging module is used for judging whether the simulation air spring axisymmetric model meets the simulation precision requirement or not;

the second modeling module includes:

generating a solid finite element network model module for generating a solid finite element network model;

defining an auxiliary flexible body module, which is used for defining the flexible body attribute of the capsule skin grid and is associated with the super elastic material;

the model parameter updating module is used for updating model parameters, including the attribute of a deformation body of the 3D unit and the attribute of a reinforcing rib of the plane cord line unit, redefining the attribute of a structural rigid body based on the 3D unit and updating the contact surface of the air spring part;

the boundary and load condition updating module is used for updating the whole boundary conditions in all the freedom degrees, the boundary conditions in the inflation load step and the boundary conditions in the axial displacement load step;

the second finite element model solving module is used for solving an air conditioner spring entity analysis model;

the first simulation precision judging module is used for judging whether the finite element model of the air spring entity meets the requirement of simulation precision or not;

the modeling and simulation analysis module comprises:

the leading-in entity model module is used for leading in the high-precision air spring entity model;

the air spring model posture correction module is used for correcting the posture of the air spring model;

the air spring model position correction module is used for correcting the position of the air spring model;

the first air suspension loading module is used for loading the air suspension;

the second simulation precision determining module is used for determining whether the vertical load of the wheel center of the air suspension model meets the precision requirement;

the intensity simulation analysis module comprises:

the model replacement module is used for guiding the grid into the air suspension model, adjusting the grid to a correct position and posture and keeping the auxiliary flexible body grid unchanged;

the rigid body deleting module is used for deleting rigid body models and reference points which are not involved in the structural member strength simulation analysis model;

introducing an auxiliary analysis structure module for introducing structural grids necessary for strength analysis of the air spring system structural member into the air suspension model except for an analysis object;

the contact defining module is used for defining a contact surface and all contact pairs related to the contact surface;

the material and attribute definition module is used for defining actual material characteristics and defining attributes according to the structure and grid characteristics;

the model solving module is used for extracting a stress field S of the second load step structural member after solving the strength analysis model;

the intensity checking and optimizing module comprises:

the strength checking module is used for checking the strength of the air spring system structural member;

and the structure optimization module is used for optimizing the air spring system structural member until the requirements are met.

In a third aspect, embodiments of the present invention further provide a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement a method for designing a structural member of an air spring system according to any one of the embodiments of the present invention.

In a fourth aspect, embodiments of the present invention further provide a computer-readable storage medium, on which a computer program is stored, which when executed by a processor, implements an air spring system structural member design method as described in any one of the embodiments of the present invention.

The invention has the beneficial effects that:

1) the invention adopts a flexible body auxiliary method modeling and fluid-solid coupling solving combination method to analyze the structural strength, and each increment step of simulation analysis adjusts the contact state and the structural rigidity according to the analysis result to correctly describe the large deformation mechanical behavior of the flexible structure under the loading of the structure. Errors caused by the types and the connection positions of the connection units in finite element modeling are avoided, and the simulation precision is ensured;

2) the invention adopts system analysis to replace single piece analysis, correctly reflects the assembly clearance and contact relation change under the loaded condition and improves the structural simulation precision.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a diagram of a membrane type air spring structure and an axisymmetrical finite element model;

FIG. 2 is a schematic view of an air conditioner load-displacement curve;

FIG. 3 is a flow chart of a method for designing structural members for an air spring system;

FIG. 4 is a schematic diagram of an arrangement for designing structural components of an air spring system;

fig. 5 is a schematic structural diagram of an electronic device.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present invention, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.

Example one

Fig. 3 is a flowchart of a method for designing a structural member of an air spring system according to an embodiment of the present invention, where the method is applicable to a situation of designing a structural member of an air spring system, and the method can be executed by an apparatus for designing a structural member of an air spring system according to an embodiment of the present invention, and the apparatus can be implemented in a software and/or hardware manner, as shown in fig. 3, the method specifically includes the following steps:

the specific method of the first step is as follows:

11) establishing an air spring axial symmetry analysis model;

the air spring modeling can be performed by using general finite element analysis software such as Abaqus or Mrac. At least 4 layers of grids are ensured in the thickness direction of the rubber bag skin. And the symmetrical axis of the air spring axisymmetric model is ensured to be coincident with the coordinate axis, otherwise, the posture of the model is adjusted.

12) Establishing an auxiliary flexible body;

where the parameters of the superelastic material may be defined based on a plurality of constitutive relations, the desired parameters are not all identical. Taking the Mooner Rivlin model as an example, three parameters of the superelastic material need to be defined: c10, C01 and D1. And the air-structure interface should be ensured to combine with the symmetry axis to form a closed cavity, otherwise the model should be adjusted to meet the requirements.

13) Defining a simulation working condition;

setting boundary conditions of axial symmetry air spring model simulation, and defining a load step: the air spring is inflated to a design target value P0, and the air spring axially displaces a load [ -U1, U1] along the direction of the symmetry axis;

14) solving a finite element model;

solving an axial symmetry simplified analysis model of the air spring, extracting the support reaction force F0 of the air spring along the direction of a symmetry axis, extracting the relation between the support reaction force and the axial displacement, generating an F-U curve, extracting the support reaction force under the condition of specified displacement, and obtaining the rigidity of the specified displacement through post-processing;

the air spring model can be solved by universal finite element analysis software such as Abaqus or Mrac, and the air spring model can be simulated and calculated based on both implicit solvers and explicit solvers. In addition, all the reinforcing cord line units are required to be ensured to be always positioned in the rubber bag skin units in the loading process, otherwise, the work from the step 11) to the step 13) is repeated, and the model precision is improved through unit embedding commands in the step 11);

generally, the extracted reaction force is a resultant force of axial reaction forces of the upper cover and the upper snap ring, or a resultant force of reaction forces of the lower cover and the lower snap ring, as shown in fig. 1. To simplify the post-processing procedure, the upper cover and the upper snap ring may be combined and processed into 1 rigid body structure in 11), and the lower cover and the lower snap ring may be processed into 1 rigid body structure in the same way.

The stiffness under the specified displacement load U2 is obtained by post-processing an F-U curve, and as shown in FIG. 2, the slope K2 of the curve at U2 is the stiffness of the air spring under the stroke.

15) Judging the simulation precision;

a) If the following conditions are satisfied:

Wherein, the suggested value position is larger than 5 positions so as to ensure the precision of the rigidity simulation.

the specific method of the second step is as follows:

the number of the grids in the circumferential direction of the air spring needs to be controlled, the simulation precision and the hexahedron grid quality are considered, and the number of the circumferential grids is recommended to be more than 100.

wherein, if the type of the applicable unit of the flexible body is different from that of other entity units, the type of the applicable unit of the flexible body needs to be modified to be the correct type.

the method aims at defining structures such as a capsule skin, an upper cover and a lower cover as entity attributes, defining a rigid body as required and ensuring that a reference point of the rigid body is always positioned on a symmetry axis of a model.

in order to ensure the contact relationship and the model convergence between the flexible capsule skin structure and other structural members, the complex contact relationship between each part of the air spring system can be represented by defining a universal contact mode.

wherein, in order to ensure the sealing performance of the fluid cavity, the bag skin part pressed by the snap ring is recommended to be processed with the upper cover and the lower cover structure grids in a joint mode.

wherein, relating to the large deformation of the super elastic material structure, in order to avoid the convergence problem, the explicit solver analysis is suggested, and the ratio of the kinetic energy and the internal energy of the model in the analysis process is required to be ensured to be less than 0.05

the third step is specifically as follows:

and if not, repeating the processes of the first step and the second step to update the solid air spring model.

The suspension model can be a finite element mesh model of a solid element or a simplified model of the combination of the rod system element and the connecting auxiliary element.

the included angle measured by the upper spring point, the lower spring point and the rigid body reference point of the upper cover is an angle formed by the axis of the solid hollow spring model and the actual axis of the spring, and the lower spring point is taken as a vertex; the central axis of rotation of the solid air spring model is defined as a straight line perpendicular to the plane defined by the three points and passing through the point below the spring.

351) the elastic damping integrated suspension is suitable for an elastic damping separated suspension, and for the elastic damping integrated suspension, a spring channel and a shock absorber channel are on the same axis, and only an upper point of the shock absorber is restrained;

when the directions of the spring and the shock absorber are not consistent with the vertical direction of the whole vehicle, support reaction force in the designated direction needs to be extracted, and the direction is consistent with the direction defined by the test.

36) Judging the simulation progress; the simulation precision is judged by comparing the test result of the air suspension system with the simulation result of the system, and the method comprises the following steps:

△Fzw _i ＝|Fzw _i -Fzw' _i | (3)

a) if the following conditions are satisfied:

△Fzw _i ≤0.01*Fzw' _i (4)

b) if the condition specified by the formula (4) is not met, judging that the simulation precision of the wheel center vertical load does not meet the requirement, repeating the operations from the step 31) to the step 35), and adjusting the rigidity property of the elastic connection unit in the model until the formula (4) is met; at the moment, judging that the simulation precision of the vertical load of the wheel center of the air suspension model meets the requirement, and turning to step 362);

a) if the following conditions are satisfied:

Wherein, because the initial stage of the test curve is unstable due to the fact that the load overcomes the assembly clearance of the system in the initial stage of the test loading, the stage of unstable test signals is avoided in the precision comparison

Fourthly, simulation analysis of structural part strength;

the concrete method of the fourth step is as follows:

wherein, the grid of the air spring structural member in the step 41) needs to satisfy the following conditions:

a) the axisymmetric structure adopts a first-order hexahedral mesh, the surface of the chamfer position is divided into more than 3 rows of units, and the meshes in the thickness direction of the structure are ensured to be more than 4 layers.

b) The non-axisymmetric structure adopts a second-order tetrahedral mesh, the mesh angle is between 15 and 120 degrees, the surface division of the chamfer position is more than 3 rows of units, and any position of the structure is ensured to exceed 2 layers of units along the thickness direction.

in which, in addition to analyzing the target structure, rigid structures are kept as much as possible. Taking the above lid strength analysis as an example, the lower lid model may be maintained as rigid body attributes, as may the upper lid structure rigid body attributes in the lower lid strength analysis.

the air spring system structure analysis method is mainly used for providing a high-precision load transmission mode and boundary conditions for structure analysis. In particular, for the suspension model of the linkage unit, an auxiliary analysis structure has to be introduced. Taking the above-mentioned cover analysis as an example, a local body structure connected thereto may be introduced and boundary conditions may be defined at the edges of the body mesh. The lower cover analysis may incorporate control arms and associated structural grids fitted thereto and defining contact and connection relationships with each other.

wherein, for the structure with complex model or contact relation, it is suggested to define the universal contact.

for auxiliary structures with higher rigidity, such as a vehicle body connecting longitudinal beam in the upper cover analysis, rigid body attributes are suggested to be defined. For less rigid or deformation-involved structures, such as the lower control arm of an E-type multi-link, it is recommended to define the deformation properties.

461) defining an air spring inflation load step; restraining 1-6 degrees of freedom of the upper point of the air spring, the upper point of the shock absorber, the connection point of the auxiliary frame and the vehicle body, restraining the vertical degree of freedom of the wheel center, inflating the air spring to a specified attitude pressure target P0, and extracting the vertical support reaction force Fzw0 of the wheel center at the moment;

The wheel center vertical jumping stroke limit corresponds to the limit state of air spring compression, and the air spring bears the maximum load under the design condition.

Fifthly, checking and optimizing the strength of the structural part;

the concrete method of the fifth step is as follows:

n＝σ _max /[σ] (7)

a) if the following conditions are satisfied:

n>1 (8)

judging that the structural member meets the strength design requirement, and ending the process;

If the number of the dangerous positions of the structure is small, structural optimization is proposed for the dangerous positions independently; if the number of the positions which do not meet the design requirement is large, the structural optimization is carried out by combining professional structural optimization simulation software, and stress conditions can be set as optimization constraints or optimization targets in the structural optimization simulation.

Example two

Referring to fig. 4, an air spring system structural member design apparatus includes:

the first modeling module includes:

and the simulation precision judging module is used for judging whether the simulation air spring axisymmetric model meets the simulation precision requirement.

the second modeling module includes:

and the first simulation precision judging module is used for judging whether the finite element model of the air spring entity meets the requirement of simulation precision.

the modeling and simulation analysis module comprises:

the first air suspension loading module is used for loading the air suspension;

and the second simulation precision determining module is used for determining whether the vertical load of the wheel center of the air suspension model meets the precision requirement.

the intensity simulation analysis module comprises:

and the model solving module is used for extracting the stress field S of the second load step structural member after solving the strength analysis model.

The intensity checking and optimizing module comprises:

EXAMPLE III

Fig. 5 is a schematic structural diagram of a computer device in a third embodiment of the present invention. FIG. 5 illustrates a block diagram of an exemplary computer device 102 suitable for use in implementing embodiments of the present invention. The computer device 102 shown in fig. 5 is only an example and should not bring any limitations to the functionality or scope of use of embodiments of the present invention.

As shown in fig. 5, computer device 102 is in the form of a general purpose computing device. The components of computer device 102 may include, but are not limited to: one or more processors or processing units 16, a system memory 28, and a bus 18 that couples various system components including the system memory 28 and the processing unit 16.

Bus 18 represents one or more of any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, and a processor or local bus using any of a variety of bus architectures. By way of example, such architectures include, but are not limited to, Industry Standard Architecture (ISA) bus, micro-channel architecture (MAC) bus, enhanced ISA bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus.

Computer device 102 typically includes a variety of computer system readable media. Such media can be any available media that is accessible by computer device 102 and includes both volatile and nonvolatile media, removable and non-removable media.

The system memory 28 may include computer system readable media in the form of volatile memory, such as Random Access Memory (RAM)30 and/or cache memory 32. The computer device 102 may further include other removable/non-removable, volatile/nonvolatile computer system storage media. By way of example only, storage system 34 may be used to read from and write to non-removable, nonvolatile magnetic media (not shown in FIG. 5, and commonly referred to as a "hard drive"). Although not shown in FIG. 5, a magnetic disk drive for reading from and writing to a removable, nonvolatile magnetic disk (e.g., a "floppy disk") and an optical disk drive for reading from or writing to a removable, nonvolatile optical disk (e.g., a CD-ROM, DVD-ROM, or other optical media) may be provided. In these cases, each drive may be connected to bus 18 by one or more data media interfaces. Memory 28 may include at least one program product having a set (e.g., at least one) of program modules that are configured to carry out the functions of embodiments of the invention.

A program/utility 40 having a set (at least one) of program modules 42 may be stored, for example, in memory 28, such program modules 42 including, but not limited to, an operating system, one or more application programs, other program modules, and program data, each of which examples or some combination thereof may comprise an implementation of a network environment. Program modules 42 generally carry out the functions and/or methodologies of the described embodiments of the invention.

The computer device 102 may also communicate with one or more external devices 14 (e.g., keyboard, pointing device, display 24, etc.), with one or more devices that enable a user to interact with the computer device 102, and/or with any devices (e.g., network card, modem, etc.) that enable the computer device 102 to communicate with one or more other computing devices. Such communication may be through an input/output (I/O) interface 22. In the computer device 102 of the present embodiment, the display 24 is not provided as a separate body but is embedded in the mirror surface, and when the display surface of the display 24 is not displayed, the display surface of the display 24 and the mirror surface are visually integrated. Also, the computer device 102 may communicate with one or more networks (e.g., a Local Area Network (LAN), a Wide Area Network (WAN), and/or a public network, such as the Internet) via the network adapter 20. As shown, the network adapter 20 communicates with the other modules of the computer device 102 over the bus 18. It should be appreciated that although not shown in the figures, other hardware and/or software modules may be used in conjunction with the computer device 102, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems, to name a few.

Processing unit 16 executes programs stored in system memory 28 to perform various functional applications and data processing, such as implementing an air spring system structural member design method provided by embodiments of the present invention.

Example four

A fourth embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements a method for designing a structural member of an air spring system according to any of the embodiments of the present invention.

Any combination of one or more computer-readable media may be employed. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C + + or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider).

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the particular embodiments described herein, and that various obvious changes, rearrangements and substitutions will now be apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for designing a structural member of an air spring system, comprising the steps of:

fourthly, simulation analysis of structural part strength;

and fifthly, checking and optimizing the strength of the structural part.

2. The method of claim 1, wherein the method of step one is as follows:

11) establishing an air spring axial symmetry analysis model;

12) establishing an auxiliary flexible body;

13) defining a simulation working condition;

14) solving a finite element model;

15) judging the simulation precision;

selecting a plurality of points on the F-U curve according to the displacement condition, and calculating the air spring support reaction force difference delta F ″, according to the formula (1) _i Difference value delta K' from air spring rigidity _i ：

In the formula, Fd _i Is the axial force on the design target curve; kd _i Is the axial force and stiffness on the design target curve; f' _i The axial force difference of the air spring simulation curve under the corresponding load condition is obtained; k' _i The rigidity difference of the air spring simulation curve under the corresponding load condition is shown.

a) If the following conditions are satisfied:

3. The method for designing a structural member of an air spring system according to claim 2, wherein the specific method of the second step is as follows:

25) updating the boundary and the load condition; defining the integral boundary conditions in all the freedom degrees, the boundary conditions in the step of inflating load and the boundary conditions in the step of axial displacement load;

Wherein, Δ F ″) _i The difference value of the support reaction force of the air spring is obtained; delta K _i Is the air spring stiffness difference: fd _i Is the axial force on the design target curve; kd _i Is the axial force and stiffness on the design target curve; f' _i The axial force difference of the air spring simulation curve under the corresponding load condition is obtained; k' _i The rigidity difference of the air spring simulation curve under the corresponding load condition is obtained;

4. the method for designing a structural member of an air spring system according to claim 1, wherein the specific method of the third step is as follows:

△Fzw _i ＝|Fzw _i -Fzw′ _i | (3)

a) if the following conditions are satisfied:

△Fzw _i ≤0.01*Fzw′ _i (4)

a) if the following conditions are satisfied:

5. The method for designing a structural member of an air spring system according to claim 1, wherein the method of step four comprises the following steps:

44) defining a contact; defining contact surfaces for the models introduced in step 41) and step 43), and all contact pairs involved by the contact surfaces;

and the suspension displacement is defined as the vertical up-jump travel limit of the wheel center, and the stress field S of the second load step structural member is extracted after the strength analysis model is solved.

6. The method of claim 5, wherein the method of step five is as follows:

51) checking the strength; structural strength is checked as specified by equation (7):

n＝σ _max /[σ] (7)

a) if the following conditions are satisfied:

n>1 (8)

7. An air spring system structural member design device, comprising:

8. An air spring system structural member design arrangement according to claim 1,

the first modeling module includes:

the second modeling module includes:

the modeling and simulation analysis module comprises:

the first air suspension loading module is used for loading the air suspension;

the intensity simulation analysis module comprises:

the deleting rigid body module is used for deleting rigid body models and reference points which are not involved in the structural part strength simulation analysis model;

the intensity checking and optimizing module comprises:

9. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor when executing the program implements a method of designing a structural member for an air spring system of any one of claims 1-6.

10. A computer-readable storage medium having stored thereon a computer program, wherein the program, when executed by a processor, implements an air spring system structural member design method as recited in any one of claims 1-6.