Research On NVH Performance Of SUV Body In White Structure

Nowadays,more and more rigorous noise control rules and increasing occupants comfort demand on car make automobile manufacturer pay more attention to the research and improvement performance of auto NVH.In order to save the cost and shorten the development period of vehicle,it has very important significance to accurately predict and analyze the body NVH performance in the design phase.Through in-depth research on modal characteristics and static stiffness characteristics of SUV body in the development and design phase,this paper developed a set of BIW(body in white)NVH structure performance study and optimized process.It plays a guiding role in the development of the subsequent models for the car companies.In this paper,the main research work is as follows:(1)Research on BIW structure finite modeling and modal.Firstly a finite model of the SUV BIW is established,and on the basis of in-depth study of modal theory,modal simulation analysis is carried out and the modal parameters such as natural frequency and vibration mode are gained;Then the modal test was finished and accuracy of the experimental modal parameters is verified by modal confidence criterion(MAC);Finally the comparison of the simulation results and test results is made.The research results show that in addition to the first order torsional modal frequency of the body,other modal parameters achieved the goals and objectives,and to ensure the vehicle performance,follow-up structural optimization is made.(2)Research on the BIW static stiffness.Firstly the body stiffness calculation theory is in-depth studied,the vehicle bending and torsional stiffness as well as the deformation of main opening of car body is received after the stiffness simulation analysis;Then relevant parameters and evaluation index are gained through stiffness test;Finally the stiffness simulation results are compared with the test results.The research results show that the test and the theoretical results fit well with the simulation results of evaluation indexes,the static stiffness performance of the SUV BIW meets the demand of NVH performance target and the research method is feasible.(3)BIW structure optimization based on NVH performance index.Firstly design variables are decided through comprehensive sensitivity method and the modal strain energy method.And the optimal target of NVH performance index is used to establish the optimal mathematical model.Finally the body structure of the optimized NVH performance is simulated to verify the optimal feasibility.The research results show that the optimized the body structure of NVH performance of the body has improved and all of them meet the requirement of performance goals,and the body weight loss is about 5.7% compared with the precious one.To certain extent,the lightweight of car body is realized.