Simulation and Optimization of Nonlinear Structures on Low Frequency Vibration and Noise of Lightweight Car Body

Abstract

Accurate models, optimization methods and improvement measures are three key issues in the design and optimization of complex structures in the field of vibration and noise. Due to the increase of passenger vehicle structure complexity and lightweight demand, nonlinear materials and structures increase obviously in the whole system. Not only different structural adhesives are used to strong body structures under the lightweight requirement, but also the influence of the windshield should be considered in the structural design process. The first point of this paper is to use the model matching method to build an accurate finite element model that takes into account nonlinear materials and structures for the next optimization. Although the optimization method can also achieve structural improvement, it cannot find the regular conclusion that has a significant impact on the performance of the structure inherently. The second innovation is to propose a combination method of sensitivity analysis and modal strain energy (MSE) indication. The method not only finds a specific weak structure, but also summarizes viewpoints that the whole stiffness mismatch characters and the weak local structure destroyed balance of the whole structure. These conclusions provide the basis for further improvement. It is a difficult problem to solve low-frequency vibration and noise problem because of their long wavelength and strong penetration ability. As the third innovation point, three-dimensional phononic crystal simulation is done to optimize the low-frequency noise of structure in this paper. The synthesis method including the above three key points has a very good effect in suppressing low-frequency vibration and noise in the vehicle. This method is also suitable for simulation and optimization of other complex structures.