1. An automobile frame structure optimization method is characterized by comprising the following steps: establishing a frame initial scheme topological optimization model to obtain an initial optimization topological result; identifying and verifying the initial topological optimization result to complete the frame design scheme; optimizing the beam system section size and position parameters of the frame based on the frame design scheme to obtain a beam system optimization topological result; optimizing the size of the plate material thickness of the frame based on the beam system optimization topological result to obtain a final optimization topological result;

the method for optimizing the beam system position parameters comprises the following steps: and dividing the frame model into an optimization part model and a non-optimization part model, connecting the optimization part model and the non-optimization part model, and optimizing the position parameters of the optimization part model and the non-optimization part model.

2. The method for optimizing the frame structure of the automobile according to claim 1, wherein: the method for dividing the frame model into the optimized part model and the non-optimized part model comprises the following steps: and dividing the part with the active optimization adjustment requirement in the frame model to form an optimization part model, and taking the rest part without the active optimization adjustment requirement as a non-optimization part model.

3. The method for optimizing the frame structure of the automobile according to claim 1, wherein: the method for connecting the optimization part model and the non-optimization part model comprises the following steps: and connecting the optimized part model and the non-optimized part model by a one-dimensional connection mode of connecting the dependent part parts.

4. The method for optimizing the frame structure of the automobile according to claim 1, wherein: the method for optimizing the position parameters of the optimization part model and the non-optimization part model comprises the following steps: and reconstructing the optimization part model into a parameterized model, setting required optimization parameters, reading a parameter file of the optimization part model, extracting and identifying the required optimization parameters, and driving the parameterized model to change and optimize according to the required optimization parameters.

5. The method for optimizing the frame structure of the automobile according to claim 1 or 4, wherein: the method for optimizing the position parameters of the optimization part model and the non-optimization part model comprises the following steps: and setting non-optimized part movement parameters for adjusting the non-optimized part model, connecting the non-optimized part movement parameters of the non-optimized part model with the optimized part movement parameters corresponding to the optimized part model, driving the non-optimized part model to move according to the set non-optimized part movement parameters, and simultaneously moving the optimized part model together according to the corresponding optimized part movement parameters.

6. The method for optimizing the frame structure of the automobile according to claim 1, wherein: the method comprises the steps of dividing a frame model into an optimization part model and a non-optimization part model, connecting the optimization part model and the non-optimization part model, storing the optimization part model, the non-optimization part model, a connection file for connecting the optimization part model and the non-optimization part model and a working condition loading file, assembling the models and the files, and analyzing and optimizing.

7. The method for optimizing the frame structure of the automobile according to claim 1, wherein: the method for establishing the vehicle frame initial scheme topological optimization model and obtaining the initial optimized topological result comprises the following steps: according to a frame design boundary, a frame concept grass data entity grid model is established, material attributes are given, topological optimization is carried out on a frame according to preset torsional rigidity, bending rigidity and modal boundary conditions, an optimization area is determined, optimization variables, optimization targets and constraint conditions are set, optimization of combined working conditions is carried out by utilizing multi-constraint setting, target requirements which need to be met under different working conditions are converted into constraints, the integral quality fraction of the topological model is set as a target to be optimized, and an initial optimization topological result is obtained.

8. The method for optimizing the frame structure of the automobile according to claim 1, wherein: the method for identifying and verifying the initial topological optimization result to complete the frame design scheme comprises the following steps: analyzing, verifying and screening the initial optimization topological result, identifying a force transmission path of topological optimization, converting the force transmission path into an actual effective scheme according to a reference structure, analyzing and verifying the effectiveness under the real finite element analysis working condition, and finally screening the effective scheme to complete the frame design scheme.

9. The method for optimizing the frame structure of the automobile according to claim 1, wherein: based on the frame design scheme, the method for optimizing the beam system section size and the position parameters of the frame comprises the following steps: based on a frame design scheme, a parameterized assembly relation between parts is established through a mapping relation, three-dimensional size and position parameters of a beam system section X, Y, Z are set as design variables according to working conditions set during establishing of a frame initial scheme topological optimization model, and optimization of size and position parameters of a beam system end face is carried out through an external entity grid.

10. The method for optimizing the frame structure of the automobile according to claim 1, wherein: based on the beam system optimization topological result, the method for optimizing the size of the plate material thickness of the frame to obtain the final optimization topological result comprises the following steps: and based on the beam system optimization topological result, according to the working condition set during the establishment of the frame initial scheme topological optimization model, carrying out sensitivity analysis and optimization on the material thickness of each sheet metal part of the frame assembly to obtain a final optimization topological result.

Background

The concept design stage plays a crucial role in the vehicle development process, particularly the platform development process, and has the characteristics of few product constraint boundaries and high design freedom degree. For the early design of the frame structure, a large number of candidate solutions generally need to be studied, sometimes even completely different frame configurations and load path strategies need to be considered. The goodness of the design at this stage will directly have a significant impact on cost control and performance. Therefore, design modification is rapidly realized within a limited time, various performances such as structure, NVH (noise, vibration and harshness), collision safety and the like are evaluated, an optimization scheme is effectively provided, a direction is provided for design, and the CAE is a key technology to be solved when the CAE is applied to a concept stage. With the enhancement of domestic autonomous research and development capability, how to effectively apply the CAE technology to the conceptual design stage to realize the driving and guidance of the design by simulation analysis has gradually become a subject of great concern.

The CAE technology has been developed at a high speed in recent years, and various application software and simulation analysis methods are introduced into each link of vehicle development and production, so as to gradually form a research and development flow with parallel design and analysis. In the product development stage, firstly, carrying out related performance simulation analysis on the 3D data of the design scheme, carrying out design improvement on the unsatisfied items according to the analysis result, carrying out finite element modeling and reanalysis after updating the 3D data until the performance requirements are met, then carrying out trial production on the sample piece and the sample car, and carrying out test verification. The technical scheme saves the cost of later-stage test verification and effectively shortens the product development period.

The main simulation analysis of the vehicle body structure by the method is mostly limited to verification work, performance verification in each round is mostly performed after 3D data design of a product is completed, the significance of development and improvement of the product is limited, guidance effect on the design is lacked, and when the requirements of arrangement, process, performance and the like are finally met, the method usually goes through multiple rounds of detailed data design and CAE grid modeling and analysis, consumes a large amount of manpower and material resources, and has a long period.

In order to reduce the performance risk of the later stage of product design, at the earlier stage of development of an automobile platform or an automobile model, because the data of the whole automobile is still in a concept stage, no detailed 3D data can be used for CAE (computer aided engineering) simulation analysis, a plurality of host factories generally adopt establishment of an initial frame space model based on a basic automobile model, whole automobile framework arrangement and the like, an entity grid finite element model for topology optimization is established according to the initial frame model, topology optimization is carried out, after the optimization is completed, an optimization result is analyzed, 3D data of an optimization scheme is established, then finite element grid division and analysis verification are carried out, and the purpose that less materials are added at a proper position to realize great performance improvement is achieved. In the later stage of frame design, part of the frame enterprises optimize the size of the frame according to the thickness of each plate material, and adopt the traditional Morph tool to optimize the section simply, and analyze and verify the final optimization scheme. And establishing 3D data of the optimization scheme according to the analyzed optimization result, verifying the optimization effect, adjusting the optimization scheme according to the optimization effect, establishing the 3D data, and repeating the steps until a result meeting the requirement is obtained, wherein the workload is still large, and the time period is long. The cross section size is optimized by using a traditional grid deformation tool, the grid quality is reduced when the grid deformation is large, and the analysis requirement of related performance cannot be met. When other parameterized models are used for optimization, parameters of local models in the models are optimized, but the problem that the undefined parameter partial models follow the parameters to follow the positions, and an integral model is needed for analysis cannot be solved.

Disclosure of Invention

The invention aims to solve the defects of the background art and provides an automobile frame structure optimization method.

The technical scheme of the invention is as follows: a vehicle frame structure optimization method comprises the steps of establishing a frame initial scheme topological optimization model to obtain an initial optimization topological result; identifying and verifying the initial topological optimization result to complete the frame design scheme; optimizing the beam system section size and position parameters of the frame based on the frame design scheme to obtain a beam system optimization topological result; optimizing the size of the plate material thickness of the frame based on the beam system optimization topological result to obtain a final optimization topological result;

the method for optimizing the beam system position parameters comprises the following steps: and dividing the frame model into an optimization part model and a non-optimization part model, connecting the optimization part model and the non-optimization part model, and optimizing the position parameters of the optimization part model and the non-optimization part model.

The method for dividing the frame model into the optimized part model and the non-optimized part model further comprises the following steps: and dividing the part with the active optimization adjustment requirement in the frame model to form an optimization part model, and taking the rest part without the active optimization adjustment requirement as a non-optimization part model.

Further methods of connecting the optimized portion model and the non-optimized portion model include: and connecting the optimized part model and the non-optimized part model by a one-dimensional connection mode of connecting the dependent part parts.

The method for optimizing the position parameters of the optimization part model and the non-optimization part model further comprises the following steps: and reconstructing the optimization part model into a parameterized model, setting required optimization parameters, reading a parameter file of the optimization part model, extracting and identifying the required optimization parameters, and driving the parameterized model to change and optimize according to the required optimization parameters.

The method for optimizing the position parameters of the optimization part model and the non-optimization part model further comprises the following steps: and setting non-optimized part movement parameters for adjusting the non-optimized part model, connecting the non-optimized part movement parameters of the non-optimized part model with the optimized part movement parameters corresponding to the optimized part model, driving the non-optimized part model to move according to the set non-optimized part movement parameters, and simultaneously moving the optimized part model together according to the corresponding optimized part movement parameters.

The frame model is further divided into an optimization part model and a non-optimization part model, the optimization part model and the non-optimization part model are connected, the optimization part model, the non-optimization part model, a connection file for connecting the optimization part model and the non-optimization part model and a working condition loading file are stored, and the optimization part model, the non-optimization part model, the connection file and the working condition loading file are assembled for analysis and optimization.

Further, the method for establishing the vehicle frame initial scheme topology optimization model and obtaining the initial optimization topology result comprises the following steps: according to a frame design boundary, a frame concept grass data entity grid model is established, material attributes are given, topological optimization is carried out on a frame according to preset torsional rigidity, bending rigidity and modal boundary conditions, an optimization area is determined, optimization variables, optimization targets and constraint conditions are set, optimization of combined working conditions is carried out by utilizing multi-constraint setting, target requirements which need to be met under different working conditions are converted into constraints, the integral quality fraction of the topological model is set as a target to be optimized, and an initial optimization topological result is obtained.

Further identifying and verifying the initial topological optimization result, and the method for completing the frame design scheme comprises the following steps: analyzing, verifying and screening the initial optimization topological result, identifying a force transmission path of topological optimization, converting the force transmission path into an actual effective scheme according to a reference structure, analyzing and verifying the effectiveness under the real finite element analysis working condition, and finally screening the effective scheme to complete the frame design scheme.

Further based on the frame design scheme, the method for optimizing the beam system section size and the position parameters of the frame comprises the following steps: based on a frame design scheme, a parameterized assembly relation between parts is established through a mapping relation, three-dimensional size and position parameters of a beam system section X, Y, Z are set as design variables according to working conditions set during establishing of a frame initial scheme topological optimization model, and optimization of size and position parameters of a beam system end face is carried out through an external entity grid.

Further based on the beam system optimization topological result, the method for optimizing the size of the plate material thickness of the frame to obtain the final optimization topological result comprises the following steps: and based on the beam system optimization topological result, according to the working condition set during the establishment of the frame initial scheme topological optimization model, carrying out sensitivity analysis and optimization on the material thickness of each sheet metal part of the frame assembly to obtain a final optimization topological result.

The invention provides a full-flow structure optimization method based on a parameterized frame, which is characterized in that the frame assembly architecture form and the load path are determined at the early stage of design, the platform design is realized, the frame beam system section size and the position parameters are determined at the middle stage of design, the thickness sizes of all plate materials are determined at the later stage of design, and the optimal performance is exerted at the lowest cost.

The method optimizes the position parameters by constructing the subprogram, avoids the problem that when a local model is optimized, the part of the model without defined parameters follows the parameters to carry out position follow-up, improves the efficiency of optimizing the position parameters, is convenient for optimization operation, and has great popularization value.

Drawings

FIG. 1: the flow diagram of the optimization method of the embodiment is shown.

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, it is to be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

The invention is described in further detail below with reference to the figures and the specific embodiments.

As shown in fig. 1, the embodiment describes an automobile frame structure optimization method, which specifically includes the following steps:

the first step is as follows: establishing a topological optimization model of an initial scheme of a vehicle frame

Establishing a frame concept scheme grid model according to a frame design boundary, setting the material attribute of the constructed frame, carrying out topological optimization on the frame according to preset torsional rigidity, bending rigidity and modal boundary conditions, determining an optimized region, setting an optimized variable, an optimized target and constraint conditions, optimizing combined working conditions by utilizing multi-constraint setting of OptiStruct software, converting target requirements required to be met under different working conditions into constraints, setting the integral mass fraction of the topological model as a target, and optimizing to obtain an initial optimized topological result;

taking the torsional rigidity and the bending rigidity of the frame as examples, on one hand, the torsional rigidity and the deformation at a bending rigidity loading point of the conceptual frame structure are taken as the performance target of the topological optimization, namely the maximum deformation of the loading point or the required area is minimum (namely the rigidity required by the performance target is maximum), and on the other hand, the mass fraction of the topological space is less than 30% as the constraint condition of the optimization, so that the system obtains a force transmission path of a key area according to the required proportion; in addition, a dispersion parameter of topology optimization is needed to be set, the purpose is to eliminate the checkerboard phenomenon in the optimized structure, the density value of the material is controlled, the density value of the material is gathered to the two ends of 0 and 1, a more definite load transfer path and structural material distribution are obtained, and the dispersion value of the embodiment is 0-3;

the second step is that: and (3) quickly identifying and verifying a topological optimization result to complete the design of a frame:

according to the initial optimized topology result, a parameterized model established based on a vehicle frame concept scheme is utilized to quickly analyze, verify and screen the initial optimized topology result, the force transmission path of topology optimization is identified by combining the characteristics of quick change of the parameterized model and integration of CAD and CAE, and the force transmission path is converted into an actual effective scheme (the actual effective scheme means a scheme capable of being applied to actual engineering, namely the existing process and equipment can be normally produced to meet the requirements of manufacturing processes, for example, a beam needs to be added at a certain optimized position, but the added beam needs to be produced according to the past experience or a similar reference structure and a beam system structure capable of being produced under the existing production and manufacturing conditions), carrying out analysis and verification on effectiveness under the real finite element analysis working condition, and finally screening out an effective scheme and implementing the effective scheme into the frame design;

the optimal material distribution in a given space can be obtained by performing finite element calculation on the definition and the setting (meaning the definition and the optimization variables of the loading boundary condition, the setting of the optimization target and the constraint condition) in the first step, and the specific process is as follows: according to the performance target, performing topological optimization analysis and finite element calculation, acquiring the material distribution condition (the condition that the influence is larger in the embodiment and the density value of the corresponding structural material is in a range of more than 0.3 and less than 1) which is greatly influenced by the relevant working conditions on the system structure, and taking the position with the larger unit density in the material distribution which is greatly influenced by the relevant working conditions as a design area of a force transmission path after optimization, so that a vehicle body frame can be designed more specifically, and the cross beam, the longitudinal beam, the reinforcing plate and the like in a vehicle body model are reasonably arranged, wherein the position of the welding line which is greatly influenced by the relevant performance is the position of the density value of the corresponding structural material in a range of more than 0.3 and less than 1; the optimization results can be directly realized in a parameterized model by adjusting related parameters, and are quickly converted into finite element data, the related working conditions are quickly verified, the effective scheme is implemented in the frame design, the frame design of the frame is completed, and the frame design scheme of the frame is obtained;

the third step: optimizing the section size and position parameters of the beam system based on the design scheme of the frame

And updating the frame design scheme completed in the second step to a frame parametric model established based on a frame concept scheme, namely the geometric shape of the model has 3 types of parameter control: the positions of control points, the curvature of a line and the shape of a section are controlled, and a parameterized assembly relation among parts is established through a mapping relation, and because all parameters are logically related to each other, the change of each parameter can cause the peripheral related parameter to correspondingly change; based on the model, according to the working conditions involved in the first step, three-dimensional size and position parameters of the section X, Y, Z of each main beam system (mainly referring to beam systems such as longitudinal beams and transverse beams with large influence on performance) are set as design variables, and aiming at an external entity grid (a part outside a main structure of the frame, which is connected with a chassis part through the external entity grid and has large influence on the performance of the frame, the part needs to be considered in an optimization model), the optimization of the position parameters is realized by compiling subroutines, and a beam system optimization topological result is obtained;

the method for writing the subprogram to realize the optimization of the position parameters comprises the following steps:

the frame parametric model (including the external solid grid) is divided into an optimization part model and a non-optimization part model, the division method is to divide the part of the frame parametric model with the active optimization adjustment requirement to form the optimization part model, and the rest part without the active optimization adjustment requirement is used as the non-optimization part model;

connecting the optimized part model and the non-optimized part model by software such as rigid and the like by using a connection mode such as part or set dependent parts, independently saving the connection mode as a connection file, and assembling the optimized part model, the non-optimized part model, the connection file, the torsion rigidity/bending rigidity and other loading files by using an include file;

reconstructing the optimization part model into an optimization part parameterized model and setting required optimization parameters;

compiling a script for controlling the movement of the model of the non-optimization part by utilizing a hypermesh secondary development script;

reading the parameter file of the parameterized model of the optimization part by using optimization platform software, extracting and identifying optimization parameters, and driving the parameterized model of the optimization part to change according to the parameters and generate a new optimization part model;

reading the control movement distance in the script and setting parameters by using an optimization platform (light), simultaneously connecting the movement parameters of the non-optimization part with the corresponding parameters of the optimization part (corresponding to the condition that the parts have a connection relation and the movement of one part can affect the other corresponding part) (for example, setting the movement parameter value of the non-optimization part to be equal to the movement parameter value of the optimization part), driving the model of the non-optimization part to move according to the set movement parameter of the non-optimization part, and moving the parameterized model of the optimization part together according to the set movement parameter value of the optimization part;

the fourth step: optimizing the size of the material thickness of each plate of the frame assembly

Based on the beam system optimization topological result, in order to further improve the relevant performance and light weight, the sensitivity analysis and optimization are carried out on the material thickness of each sheet metal part of the frame assembly according to the working conditions involved in the first step; in the embodiment, a relative sensitivity analysis method is adopted, namely the ratio of the rigidity sensitivity to the mass sensitivity is used for identifying which parts can reduce the material thickness and which parts need to increase the material thickness, the method can prevent parts with large mass and mass reduction from being ignored due to larger direct sensitivity, and the selection of design variables can obtain higher efficiency by utilizing the relative sensitivity analysis;

and after the material thickness data are obtained, a final optimized topological result is obtained based on the beam system optimized topological result.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are given by way of illustration of the principles of the present invention, and that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.