| As one of the important components of the car chassis,the sub-frame acts to reduce the excitation of the engine and the road surface,so that the vibration of the cab is controlled within the comfort range of the human body.At present,the design and simulation process of the subframe is very cumbersome,including a lot of engineering knowledge and repetitive work.This makes the individual requirements of the engineer higher,which indirectly increases the cost of training the enterprise.This paper combines KBE(knowledge based engineering)technology,NX software as the platform,Visual Studio as the development tool,complete the model configuration and simulation configuration software development of the sub-frame.By configuring the software,engineers can greatly improve the design efficiency and quality of the sub-frame,which has important practical significance for shortening the product development cycle and reducing the cost of the enterprise.In this paper,the development and simulation optimization of the front sub-frame of a company’s sedan is carried out.The content mainly includes the following three parts:(1)According to the discretization rule,the sub-frame parts are divided,and the similar features in the parts are divided into one class to facilitate the extraction of engineering rules.Based on KBE,a configuration method of the subframe frame structure is created.This knowledge base-based configuration method can generate more topology changes.The configuration of the rest of the sub-frame is completed by a program-based parameterization method.The pose matrix of the model stores the position information,calculates the coordinate system transformation between the pose matrices,and completes the automated assembly of the sub-frame parts based on the program.(2)Applying the finite element method to the performance analysis of the sub-frame,the stress distribution and the node displacement of the sub-frame are obtained through static analysis to avoid the strength damage of the sub-frame.In addition,the Lanzcos feature extraction method is selected to complete the free modal analysis of the sub-frame,and the loworder natural frequency and vibration mode are analyzed to prevent resonance between the subframe and the engine excitation or road excitation.(3)The configuration of static analysis and modal analysis is completed by NX secondary development technology.In the development process,the OLE method is used to complete the connection between the operation interface and the database,which facilitates the input and management of simulation information.Based on the static simulation results,the sensitivity of the design is used to reduce the dimension of the design variables.The minimum weight is the optimization target(function),and the Von Mises stress is used as the constraint to optimize the thickness of the sub-frame parts. |
