A SUV Vehicle Multi-body Modeling And Subframe Strength Analysis

With the continuing development of computer technology, CAE technology hasbeen widely used in automotive product design and product research. In automotiveindustry, Multi-body dynamics theory is widely used to do kinematics and dynamicssimulation analysis in order to analyze and predict the working status, performanceof parts as well as assemblies before vehicle trial production, and combining withfinite element method to perform various performance analysis, model validationand finally to guide structural optimal design. The core of simulation analysis issupposed to be Multi-body dynamics, which divide the full vehicle system intovarious subsystems in accordance with its topology, and then complete eachsubsystems modeling. On this basis, use finite element method and CAE software likeHypermesh and Nastran to do performance analysis and parts optimization.This paper takes the front subframe as example to do vehicle stiffness, modal,and strength analysis and their optimization analysis on the base of the combinationof Multi-body dynamics and Finite Element Method. Firstly, builds templates of eachassemblies, subsystems and full vehicle system with MSC Adams/Car. Secondly,conducts K&C validation and load testing validation to guide Multi-body dynamicsmodel tuning and error estimation. Thirdly, performs various static and dynamicworking condition simulation analysis with tuned virtual prototype, and extractscharacteristic parameters of vehicle dynamic performance which could be the loadand displacement boundary condition for parts strength analysis with Finite ElementMethod. Then, uses Hypermesh to establish front subframe Finite Element Model,and invokes Nastran to solve stiffness analysis and free modal analysis, and proposeoptimization scheme for the items which fail to reach the target. Finally, performssubframe strength analysis and its optimization using the results of static anddynamic working condition simulation analysis as boundary conditions.This paper effectively integrates Multi-body dynamics theory and Finite ElementMethod, systematically discusses methods of full vehicle muti-body dynamicmodeling, tuning and benchmarking, methods of parts stiffness and modal calculation and optimization, as well as parts strength analysis with the application ofmulti-body dynamics simulation results. These analysis methods provide a goodtechnical reference for similar models chassis systems research and development aswell as its reliability analysis.