Analysis And Optimization Of The NVH Performance For A Compact SUV Body In White

Body in white(BIW)is a very complicated subsystem on the car.It is the main frame of the whole vehicle.Other systems and components need to be assembled on the body.With the increasingly fierce competition in the vehicle market,the product upgrading is accelerated,and the major automobile manufacturers are reducing the product development cycle.Due to its complex structure and strong correlation with other components,the development of BIW is becoming more and more challenging.For the NVH performance development of BIW,the traditional approach is to focus on the structural layout in the early development of BIW.The performance of NVH is usually analyzed and verified after the sample car is produced.However,it means that the body mold has been developed after the prototype coming out,and any change of the vehicle may lead to many related changes of the BIW,making NVH optimization costly or almost impossible to implement.The purpose of this paper is to take a compact SUV as the research object,move forward the performance analysis and optimization of NVH,ensure the realistic design goal,reduce iteration,save development cost and shorten development cycle.Modal analysis and optimization were carried out in the early stage of development.Compared with benchmarking vehicles,five modes of car body were identified,and each mode was optimized one by one.At the same time,the dynamic stiffness of the critical attachment points is analyzed and optimized to reduce the development iteration associated with other systems.Then the effectiveness of modal and dynamic stiffness analysis optimization is verified by modal test.The optimization process pays more attention to the understanding of the structure of BIW,and discusses the development process of the vehicle and NVH.The procedure of modal test and how to ensure the accuracy of test are also introduced.The dynamic stiffness of the mounting points such as left / right suspension was analyzed and optimized to meet the design requirements of NVH of BIW.The results of simulation analysis and modal test are within 5% deviation,which verifies the effectiveness of modal and dynamic stiffness analysis and optimization.