CN115438527A - Method and device for analyzing torsional rigidity of passenger car body framework - Google Patents

Method and device for analyzing torsional rigidity of passenger car body framework Download PDF

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CN115438527A
CN115438527A CN202110627227.9A CN202110627227A CN115438527A CN 115438527 A CN115438527 A CN 115438527A CN 202110627227 A CN202110627227 A CN 202110627227A CN 115438527 A CN115438527 A CN 115438527A
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passenger car
car body
front axle
finite element
torsional rigidity
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朱红军
刘芳忠
凌志强
吴兵
孙超
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CRRC Electric Vehicle Co Ltd
Changsha CRRC Zhiyu New Energy Technology Co Ltd
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CRRC Electric Vehicle Co Ltd
Changsha CRRC Zhiyu New Energy Technology Co Ltd
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Abstract

The invention discloses a method and a device for analyzing torsional rigidity of a passenger car body framework, wherein the method comprises the following steps: establishing a passenger car body framework finite element model based on the passenger car body framework three-dimensional model; establishing a simple model of a finite element suspension; establishing boundary conditions, and respectively applying constraints on a finite element model and a simple model of a finite element suspension of a passenger car body framework; establishing a load condition, applying a load on the simple finite element suspension model, and determining a torque; carrying out mechanical solution on the finite element model of the passenger car body framework to obtain the displacement of the measuring point, and obtaining the relative torsion angle of the passenger car body framework under the action of torque; and acquiring the torsional rigidity of the bus body framework according to the relative torsional angle, and detecting whether the design scheme of the bus body framework meets the requirement of the torsional rigidity according to the torsional rigidity. The method can analyze the torsional rigidity of the body frame of the passenger car efficiently, accurately and at low cost, and can realize optimization of various design schemes and validity verification of the design schemes.

Description

Method and device for analyzing torsional rigidity of passenger car body framework
Technical Field
The invention belongs to the technical field of passenger car body structures, and particularly relates to a method and a device for analyzing torsional rigidity of a passenger car body framework.
Background
The car body framework is a main body structure of a passenger space of a passenger car, and the design scheme of the car body framework needs to ensure that the car body framework has enough torsional rigidity so that the car body framework has enough capacity of resisting torsional deformation. The insufficient torsional rigidity of the car body framework can greatly reduce the bearing capacity of the passenger car, so that the possibility of strength damage and fatigue damage of the structure is increased, and the probability of breakage of the window frame glass is increased. In addition, insufficient torsional rigidity of the body frame can reduce the mode of the body, thereby reducing the NVH (Noise-Vibration-Harshness) performance of the passenger car. Therefore, the torsional rigidity of the body frame of the passenger car needs to be strictly controlled in the early stage of design, and the cost and time cost of optimizing and modifying caused by insufficient basic performance in the later stage of product development and the using process are avoided.
In the prior art, an empirical evaluation method is generally adopted for torsional rigidity analysis of a passenger car body framework, the accuracy degree of the torsional rigidity value is influenced by the experience level of designers, a set of universal analysis and evaluation system cannot be formed in the early stage of design, and the situation that the body framework has the torsional rigidity meeting the requirements in the design, development and physical production processes cannot be guaranteed.
Disclosure of Invention
The invention aims to provide a method and a device for analyzing torsional rigidity of a passenger car body framework, and aims to solve the problem that in the prior art, the torsional rigidity of the car body framework is evaluated by an experience evaluation method, and the accuracy of the torsional rigidity is influenced by the experience level of designers.
In view of the above, the present invention provides a method for analyzing torsional rigidity of a body frame of a passenger car, comprising:
establishing a passenger car body framework finite element model based on the passenger car body framework three-dimensional model;
establishing a simple model of a finite element suspension;
establishing boundary conditions, and respectively applying constraints on the finite element model of the passenger car body framework and the simple model of the finite element suspension according to the boundary conditions;
establishing a load condition, applying a load on the simple finite element suspension model according to the load condition, and determining a torque;
carrying out mechanical solution on the finite element model of the passenger car body framework to obtain the displacement of the measuring point, and obtaining a relative torsion angle of the passenger car body framework under the action of the torque according to the displacement of the measuring point;
and acquiring the torsional rigidity of the passenger car body framework according to the relative torsional angle, and detecting whether the design scheme of the car body framework meets the torsional rigidity requirement or not according to the torsional rigidity of the passenger car body framework.
Preferably, the establishing a finite element suspension simple model comprises:
acquiring a general layout of a passenger car;
acquiring a node set under different suspension states according to the general layout of the passenger car;
and connecting all the nodes in the node set through a one-dimensional unit so as to complete the establishment of the finite element suspension simple model.
Preferably, the suspension state is a plate spring state; the acquiring of the node sets under different suspension states according to the general layout of the passenger car comprises:
and determining a front axle left wheel center, a front axle right wheel center, an intersection point of a front axle and the left plate spring, an intersection point of the front axle and the right plate spring, and a midpoint of an intersection point of the front axle and the left and right plate springs in a general layout of the passenger car, and generating the node set.
Preferably, the suspension state is an air bag state; the acquiring of the node sets under different suspension states according to the general layout of the passenger car comprises the following steps:
and determining a front axle left wheel center, an intersection point of a front axle and a left air bag, an intersection point of the front axle and a right air bag, and a midpoint of the intersection point of the front axle and the left and right air bags in a general layout diagram of the passenger car, and generating the node set.
Preferably, the establishing of the boundary condition and the applying of the constraint on the finite element model of the passenger car body framework according to the boundary condition comprise:
marking the center of the section of a main longitudinal beam of a left frame corresponding to a rear shaft in the finite element model of the body framework of the passenger car as a first constraint point, and applying translational freedom degree constraints in the front-back, left-right and up-down directions at the first constraint point; and marking the center of the section of the main longitudinal beam of the right frame corresponding to the rear shaft as the second constraint point, and applying the translational freedom degree constraint in the front-back and up-down directions at the second constraint point.
Preferably, the establishing of the boundary condition and the imposing of the constraint on the finite element suspension simple model according to the boundary condition comprise:
and marking the middle point of the intersection point of the front axle and the left and right leaf springs or the intersection point of the front axle and the left and right airbags in the finite element suspension simple model as a suspension restraint point, and applying translation freedom degree restraint in the up-down direction to the suspension restraint point.
Preferably, the establishing of the load condition, applying a load on the finite element suspension simple model according to the load condition, and determining the torque comprises:
marking the left wheel center of the front axle and the right wheel center of the front axle in the finite element suspension simple model as preset loading points;
respectively applying a first load and a second load to the left wheel center of the front axle and the right wheel center of the front axle;
obtaining a torque exerted on the front axle based on the first load and the second load.
Preferably, the torque T is calculated by the formula:
Figure BDA0003101978250000021
Figure BDA0003101978250000022
wherein T is the torque; f f For a first load in vertical direction applied at the left hub of the front axle, F r A second load in a vertical direction applied at the right wheel center of the front axle, and the first load and the second load are opposite in direction; l is the transverse distance between the left wheel center of the front shaft and the right wheel center of the front shaft; m is a group of f The front axle is full load axle weight; g is the acceleration of gravity.
Preferably, the calculation formula of the relative torsion angle is:
Figure BDA0003101978250000031
wherein alpha is the relative torsion angle of the passenger car body framework under the action of the torque; delta Z 1 The absolute value of the displacement in the up-down direction of the front axle left wheel center as a test point; Δ Z 2 The absolute value of the displacement in the up-down direction of the front axle right wheel center as a test point; k is a torsion constant.
In a second aspect, the present invention provides a passenger car body frame torsional rigidity analysis apparatus, which includes a processor, a memory, and a passenger car body frame torsional rigidity analysis program stored in the memory and operable on the processor, where the processor implements the passenger car body frame torsional rigidity analysis method of the first aspect when executing the passenger car body frame torsional rigidity analysis program.
After a three-dimensional model of a passenger car body framework and a simple model of a finite element suspension are established, firstly, respectively constraining a finite element model of the passenger car body framework and the simple model of the finite element suspension according to boundary conditions, loading the simple model of the finite element suspension according to loading conditions, determining torque to complete integral constraint and integral loading, then solving the finite element model of the passenger car body framework related to the three-dimensional model of the passenger car body framework to obtain the displacement of a measuring point, obtaining a relative torsion angle of the passenger car body framework under the action of the torque according to the displacement of the measuring point, further calculating to obtain torsional rigidity, and finally, detecting whether a design scheme of the passenger car body framework meets the requirement of the torsional rigidity according to the torsional rigidity. The method can analyze the torsional rigidity of the body frame of the passenger car efficiently, accurately and at low cost, can realize optimization of various design schemes and validity verification of the design schemes, and ensures that the design schemes of the body frame are produced and manufactured on the premise of meeting the design target of the torsional rigidity, thereby avoiding verification and optimization by using real objects, and reducing the time cost of design and development, the cost of real object verification and manufacturing and the like.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a flow chart of a method for analyzing torsional rigidity of a body frame of a passenger car according to an embodiment of the present invention;
FIG. 2 is a schematic representation of a three-dimensional model of a passenger vehicle body frame in an embodiment of the present disclosure;
FIG. 3 is a schematic diagram of a simplified model of a finite element suspension according to an embodiment of the invention;
FIG. 4 is a schematic view of a restraint position of the vehicle frame in accordance with an embodiment of the present invention;
fig. 5 is a flowchart of step S40 of a method for analyzing torsional rigidity of a body frame of a passenger car according to an embodiment of the present invention.
Detailed Description
In order to make those skilled in the art better understand the technical solutions of the present invention, 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.
As shown in fig. 1, in an embodiment, a method for analyzing torsional rigidity of a body frame of a passenger car is provided, which includes the following steps:
and S10, establishing a finite element model of the passenger car body framework based on the three-dimensional model of the passenger car body framework.
In this embodiment, the three-dimensional model of the passenger car body framework comprises a front wall three-dimensional model, a rear wall three-dimensional model, a left side wall three-dimensional model, a right side wall three-dimensional model, a top cover three-dimensional model, a frame and a floor three-dimensional model.
Specifically, a three-dimensional model of the passenger car body skeleton shown in fig. 2 is established by presetting three-dimensional drawing software such as PROE, the three-dimensional model of the passenger car body skeleton is led into preset finite element software such as Hypermesh, and the three-dimensional model of the passenger car body skeleton is subjected to geometric cleaning, meshing and other processing to obtain a finite element model of the passenger car body skeleton, namely, three-dimensional model data is converted from geometric data into finite element model data for finite element analysis.
And S20, establishing a simple finite element suspension model.
In the embodiment, the finite element front suspension simple model is formed by connecting a plurality of nodes through a one-dimensional unit. The one-dimensional unit may be an RBE2 unit (Rigid Body Element 2) or a BEAM unit.
Specifically, a general layout of the passenger car is obtained, a node set in different suspension states is obtained according to the general layout of the passenger car, and all nodes in the node set are connected through a one-dimensional unit, so that the suspension is simplified and processed into a simple finite element suspension model. The general layout of the passenger car includes information such as the overall size of the whole passenger car, the installation positions of the functional components, and the mutual position relationship among the functional components.
Preferably, the finite element suspension simple model shown in fig. 3 (in fig. 3, the left side and the right side correspond to the leaf spring state and the airbag state respectively), the method for acquiring the node sets in different suspension states according to the general layout of the passenger car may include the following steps:
when the suspension state is a plate spring state, a front axle left wheel center 1, a front axle right wheel center 2, an intersection point 3 of a front axle and the left plate spring, an intersection point 4 of the front axle and the right plate spring, and a midpoint 5 of the intersection points of the front axle and the left and right plate springs are determined in a general layout diagram of the passenger car, and a node set is generated.
When the suspension state is the airbag state, a front axle left wheel center 1, a front axle right wheel center 2, an intersection point 3 of the front axle and the left airbag, an intersection point 4 of the front axle and the right airbag, and a midpoint 5 of the intersection point of the front axle and the left and right airbags are determined in a general layout diagram of the passenger car, and a node set is generated.
That is, a front axle left wheel center 1, a front axle right wheel center 2, an intersection 3 of a front axle and a left leaf spring or a left air bag, an intersection 4 of a front axle and a right leaf spring or a right air bag, and a midpoint 5 of an intersection of a front axle and a left leaf spring or a front axle and a left air bag are determined in the general layout, and the nodes are connected by a one-dimensional unit, so that the suspension is simplified and treated as a limited simple suspension model.
The method can be used for solving the problem that the existing method is not suitable for the suspension system, and can be used for solving the problem that the existing method is not suitable for the suspension system.
And S30, establishing boundary conditions, and respectively applying constraints on the finite element model and the simple model of the finite element suspension of the passenger car body framework according to the boundary conditions.
In the embodiment, the boundary conditions are that at least one direction of translational freedom degree constraint is exerted on a framework constraint point (comprising a first constraint point and a second constraint point) of the three-dimensional model of the passenger car body framework, and at least one direction of translational freedom degree constraint is exerted on a suspension constraint point of the finite element suspension simple model. At this time, in combination with the frame constraint position schematic diagram shown in fig. 4, applying constraint on the passenger car body framework finite element model means that the center 6 of the cross section of the left frame main longitudinal beam corresponding to the rear shaft in the passenger car body framework finite element model is marked as a first constraint point, and translational freedom constraint in the front-rear direction, the left-right direction and the up-down direction is applied at the first constraint point; and marking the center 7 of the section of the main longitudinal beam of the right frame corresponding to the rear shaft as a second constraint point, and applying the translational freedom degree constraint in the front-back and up-down directions at the second constraint point.
The constraint is applied to the finite element suspension simple model, namely, a middle point 5 of an intersection point of a front shaft and a left leaf spring, a right leaf spring or a left air bag and a right air bag in the finite element suspension simple model is marked as a suspension constraint point, and the translation freedom degree constraint in the up-down direction is applied to the suspension constraint point.
It can be understood that the grabbing range of the main longitudinal beam corresponding to the rear axle is specified, the constraint freedom degrees of the left side and the right side of the main longitudinal beam corresponding to the rear axle are specified, the vehicle body framework is enabled to fully participate in deformation under the torsion action through the regulations, larger rigidity cannot be additionally increased, and the rigidity value obtained through analysis is enabled to be more practical.
In other embodiments, the boundary condition may include MPC constraints (multi-point constraints) between left and right wheel centers of the finite element suspension simplified model, and in this case, applying constraints on the finite element suspension simplified model means applying MPC constraints in the up-down direction between left and right wheel centers of a front axle in the finite element suspension simplified model.
And S40, establishing a load condition, applying a load on the simple finite element suspension model according to the load condition, and determining a torque T.
It can be understood that the bus body framework is a part of the whole bus, is an integral bearing structure, is arranged on the chassis and is driven by the chassis, the suspension is a part of the chassis, the power of the chassis is transmitted to the bus body through the suspension, and drives the bus body to advance, brake and the like, so that the load borne by the bus body framework is transmitted to the suspension firstly and then transmitted to the bus body framework through the suspension, and therefore when the torsional rigidity of the bus body framework is analyzed, the load is loaded on the suspension.
In this embodiment, addThe loading condition is that a first load F is respectively applied to preset loading points of the simple model of the finite element suspension f And a second load F r Wherein the first load F f And a second load F r Equal in size and opposite in direction. At this time, as shown in fig. 5, step S40 includes the steps of:
step S401, marking a front axle left wheel center 1 and a front axle right wheel center 2 in the finite element suspension simple model as preset loading points.
Step S402, respectively applying first loads F on the left wheel center 1 and the right wheel center 2 of the front axle f And a second load F r 。
Step S403, according to the first load F f And a second load F r Obtaining the torque T exerted on the front axle, wherein the calculation formula of the torque T can be expressed as:
Figure BDA0003101978250000061
Figure BDA0003101978250000062
in the formula (1), F f For applying a first load in the vertical direction at the left hub 1 of the front axle, F r For applying a second load in the vertical direction at the front axle right wheel center 2, and the first load and the second load are opposite in direction, i.e. if the first load direction is upward, the corresponding second load direction is downward, and if the first load direction is downward, the corresponding second load direction is upward; l is the transverse distance between the left wheel center 1 of the front axle and the right wheel center 2 of the front axle; m is a group of f The front axle is fully loaded with the axle weight; g is the acceleration of gravity.
It can be understood that, the embodiment provides an analysis method of the front axle torque load, and the load of the front axle at one side under the actual full load condition is taken as the input of the load at one side, so that the randomness caused by artificially defining the load is avoided, the load loading is in line with the reality, and the traceability is realized.
And S50, carrying out mechanical solution on the finite element model of the passenger car body framework to obtain the displacement of the measuring point, and obtaining the relative torsion angle alpha of the passenger car body framework under the action of the torque T according to the displacement of the measuring point.
The calculation formula of the relative torsion angle can be expressed as:
Figure BDA0003101978250000063
in the formula (2), alpha is a relative torsion angle of the passenger car body framework under the action of the torque T; delta Z 1 The absolute value of the displacement in the up-down direction of the front axle left wheel center 1 as a test point; delta Z 2 The absolute value of the displacement in the up-down direction of the front axle right wheel center 2 as a test point; k is a torsion constant, and k =57.3.
Understandably, the constraint applied to the finite element model of the passenger car body framework, the constraint and the load applied to the simple finite element suspension model are finally transmitted to the nodes of the finite element model of the passenger car body framework, in the step S40, the front axle left wheel center 1 and the front axle right wheel center 2 in the simple finite element suspension model are used as loading points to apply the load, in the corresponding step S50, the front axle left wheel center 1 and the front axle right wheel center 2 are used as test points to solve, and after the displacement of the measurement points is obtained, the relative torsion angle alpha of the passenger car body framework under the action of the torque T is obtained through calculation of a formula (2).
And S60, acquiring the torsional rigidity K of the passenger car body framework according to the relative torsional angle alpha, and detecting whether the design scheme of the passenger car body framework meets the torsional rigidity requirement or not according to the torsional rigidity of the passenger car body framework. Wherein, the calculation formula of the torsional rigidity is as follows:
Figure BDA0003101978250000064
in this embodiment, the torsional rigidity K of the passenger car body frame is calculated by the formula (3), and the torsional rigidity K of the passenger car body frame is compared with the target value G K Comparing, judging whether the design scheme of the vehicle body framework meets the torsional rigidity requirement or not, and judging the torsional rigidity of the vehicle body framework of the passenger carK reaches (is greater than or equal to) a target value G K Judging that the design scheme of the vehicle body framework meets the requirement of torsional rigidity, and sending a detection result that the design scheme meets the requirement; and the torsional rigidity K of the passenger car body framework does not reach (is less than) the target value G K And when the design scheme of the vehicle body framework does not meet the torsional rigidity requirement, sending a detection result that the design scheme does not meet the requirement, and further, carrying out validity verification on the design scheme and optimizing multiple design schemes according to the detection result. It will be appreciated that the torsional stiffness of the present embodiment is a front end to torsional condition.
In summary, in the method for analyzing torsional rigidity of a passenger car body framework according to the embodiment, after a three-dimensional model of a passenger car body framework and a simple model of a finite element suspension are established, firstly, a finite element model of the passenger car body framework and a simple model of the finite element suspension are respectively constrained according to boundary conditions, and the simple model of the finite element suspension is loaded according to load conditions, and torque is determined to complete integral constraint and integral loading, then, a finite element model of the passenger car body framework associated with the three-dimensional model of the passenger car body framework is solved to obtain a displacement of a measurement point, a relative torsional angle of the passenger car body framework under the action of torque is obtained according to the displacement of the measurement point, and then, torsional rigidity is calculated, and finally, whether a design scheme of the passenger car body framework meets the torsional rigidity requirement is detected according to the torsional rigidity. The method for analyzing the torsional rigidity of the passenger car body framework can analyze the torsional rigidity of the passenger car body framework efficiently, accurately and at low cost, can realize optimization of various design schemes and validity verification of the design schemes, and ensures that the design schemes of the passenger car body framework are produced and manufactured on the premise of meeting the design target of the torsional rigidity, thereby avoiding verification and optimization by using a real object, and reducing the time cost of design and development, the cost of real object verification and manufacturing and the like.
In addition, in an embodiment, a device for analyzing torsional rigidity of a passenger car body framework is further provided, and the device includes a processor, a memory, and a program for analyzing torsional rigidity of a passenger car body framework, which is stored in the memory and can run on the processor, and when the processor executes the program for analyzing torsional rigidity of a passenger car body framework, the steps of the method for analyzing torsional rigidity of a passenger car body framework in any one of the embodiments are implemented.
Those of ordinary skill in the art will understand that: the discussion of any embodiment above is meant to be exemplary only, and is not intended to intimate that the scope of the disclosure, including the claims, is limited to these examples; within the idea of the invention, also technical features in the above embodiments or in different embodiments may be combined and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity. Therefore, any omissions, modifications, substitutions, improvements and the like that may be made without departing from the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims (10)

1. A method for analyzing torsional rigidity of a passenger car body framework is characterized by comprising the following steps:
establishing a passenger car body framework finite element model based on the passenger car body framework three-dimensional model;
establishing a simple model of a finite element suspension;
establishing boundary conditions, and respectively applying constraints on the finite element model of the passenger car body framework and the simple model of the finite element suspension according to the boundary conditions;
establishing a load condition, applying a load on the simple finite element suspension model according to the load condition, and determining a torque;
carrying out mechanical solution on the finite element model of the passenger car body framework to obtain the displacement of the measuring point, and obtaining a relative torsion angle of the passenger car body framework under the action of the torque according to the displacement of the measuring point;
and acquiring the torsional rigidity of the passenger car body framework according to the relative torsional angle, and detecting whether the design scheme of the car body framework meets the torsional rigidity requirement or not according to the torsional rigidity of the passenger car body framework.
2. The method for analyzing torsional rigidity of a passenger vehicle body frame according to claim 1, wherein the establishing a finite element suspension simple model comprises:
acquiring a general layout of the passenger car;
acquiring a node set under different suspension states according to the general layout of the passenger car;
and connecting all nodes in the node set through a one-dimensional unit so as to simplify and process the passenger car suspension into a simple finite element suspension model.
3. The method for analyzing torsional rigidity of a passenger vehicle body frame according to claim 2, wherein the suspension state is a leaf spring state;
the acquiring of the node sets under different suspension states according to the general layout of the passenger car comprises:
and determining a front axle left wheel center, a front axle right wheel center, an intersection point of a front axle and the left plate spring, an intersection point of the front axle and the right plate spring, and a midpoint of an intersection point of the front axle and the left and right plate springs in a general layout of the passenger car, and generating the node set.
4. The torsional rigidity analysis method of the passenger car body frame as set forth in claim 2, wherein the suspension state is an air bag state;
the acquiring of the node sets under different suspension states according to the general layout of the passenger car comprises:
and determining a front axle left wheel center, an intersection point of a front axle and a left air bag, an intersection point of the front axle and a right air bag, and a midpoint of the intersection point of the front axle and the left and right air bags in a general layout diagram of the passenger car, and generating the node set.
5. The passenger vehicle body frame torsional stiffness analysis method of claim 1, wherein establishing boundary conditions according to which constraints are imposed on the passenger vehicle body frame finite element model comprises:
marking the center of the section of a main longitudinal beam of a left frame corresponding to a rear shaft in the finite element model of the body framework of the passenger car as a first constraint point, and applying translational freedom degree constraints in the front-back, left-right and up-down directions at the first constraint point; and marking the center of the section of the main longitudinal beam of the right frame corresponding to the rear shaft as a second constraint point, and applying translational freedom degree constraint in the front-back and up-down directions at the second constraint point.
6. The passenger vehicle body frame torsional rigidity analysis method of claim 3 or 4, wherein said establishing boundary conditions, and imposing constraints on said finite element suspension dummies according to said boundary conditions, comprises:
and marking the middle point of the intersection point of the front axle and the left and right leaf springs or the intersection point of the front axle and the left and right airbags in the finite element suspension simple model as a suspension restraint point, and applying translation freedom degree restraint in the up-down direction to the suspension restraint point.
7. The method for analyzing torsional rigidity of a passenger car body frame according to claim 3 or 4, wherein the establishing of the load condition, the applying of the load on the finite element suspension simple model according to the load condition, and the determining of the torque comprise:
marking the left wheel center of the front axle and the right wheel center of the front axle in the finite element suspension simple model as preset loading points;
respectively applying a first load and a second load to the left wheel center of the front axle and the right wheel center of the front axle;
obtaining a torque exerted on the front axle based on the first load and the second load.
8. The method for analyzing torsional rigidity of a passenger car body frame according to claim 7, wherein the calculation formula of the torque T is as follows:
Figure FDA0003101978240000021
Figure FDA0003101978240000022
wherein T is the torque; f f For a first load in the vertical direction applied at the left hub of the front axle, F r A second load in a vertical direction applied at the right wheel center of the front axle, and the first load and the second load are opposite in direction; l is the transverse distance between the left wheel center of the front shaft and the right wheel center of the front shaft; m f The front axle is fully loaded with the axle weight; g is the acceleration of gravity.
9. The method for analyzing torsional rigidity of a passenger car body frame as claimed in claim 1, wherein the calculation formula of the relative torsional angle is:
Figure FDA0003101978240000023
wherein alpha is the relative torsion angle of the passenger car body framework under the action of the torque; Δ Z 1 The absolute value of the displacement in the up-down direction of the front axle left wheel center as a test point; Δ Z 2 The absolute value of the displacement in the up-down direction of the front axle right wheel center as a test point; k is a torsion constant.
10. A passenger car body frame torsional rigidity analysis device, characterized by, including treater, memory and the passenger car body frame torsional rigidity analysis program that is stored in the memory and can be operated on the treater, realize the passenger car body frame torsional rigidity analysis method of any one of claims 1 to 9 when the treater carries out the passenger car body frame torsional rigidity analysis program.
CN202110627227.9A 2021-06-04 2021-06-04 Method and device for analyzing torsional rigidity of passenger car body framework Pending CN115438527A (en)

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