Vibration Performance Simulation And Body-in-White Structure Optimization Research

Vehicle NVH research is a study of the wide-ranging and complex integrated disciplines,the causes of vehicle NVH problems shows multi-disciplinary,multi-level and multiple system features,it has influenced the ride comfort,driving safety,fatigue,etc.The development of new models generally includes five stages: market analysis,analysis of competitive car,formulation and decomposition of various performance,the vehicle design and optimization,the prototype debugging.In the stage of design and optimization,CAE technology should be used in simulation analysis and optimization of various performance.A model of SUV white body has been built in this paper,finite element method has been used to analysis the static and vibration performance of white body,multi-objective genetic algorithm has been used to optimize and improve NVH performance of white body,all works lay a good foundation for full-vehicle vibration performance.In this paper,the main research contents and results are as follows:(1)Vehicle NVH analysis condition and its theory has been introduced,finite element model has been built,and its quality has been evaluated.(2)White body stiffness and modal conditions has been set,static bending stiffness,static torsion stiffness and modal distribution of white body have been analyzed,stiffness and modal analysis results have been evaluated.(3)White body's main incentive point of transfer function have been analyzed,transfer function performance of seat and place of accelerator pedal has been studied,amplitude of the transfer function has been evaluated in the frequency range.(4)In order to provide evidence for vibration transfer function results,origin dynamic rigidity of the excitation point has been carried on,it's results are also used to study the vibration isolation performance of the incentive points.The origin of every incentive points dynamic stiffness has been compared,also include the target of origin dynamic rigidity,all the research have showed vibration performance of the white body.(5)Through analysis of static and dynamic performance,we find the reason of poor vibration performance is the insufficient body static stiffness;In addition,white body modal frequency distribution is not reasonable,which further influence the vibration performance of the car body.(6)Aiming at the phenomenon of lower static stiffness,multi-objective genetic algorithm has been used to optimize static stiffness and modal distribution of white body,the radial basis function model of stiffness and modal is established,and theoptimization results points out the direction of improving car-body's overall performance.(7)Simulation verification of optimized white body has been done,a small change total car-body quality has lead to a great improvement of the vibration performance,the optimization progress has verified that the multi-objective genetic algorithm plays a positive role in improving vehicle vibration performance.