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.

中文翻译：

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轻型车身低频振动噪声非线性结构仿真与优化

准确的模型、优化方法和改进措施是振动与噪声领域复杂结构设计与优化的三个关键问题。由于乘用车结构复杂性和轻量化需求的增加，非线性材料和结构在整个系统中明显增加。在轻量化要求下，不仅要使用不同的结构胶来加固车身结构，而且在结构设计过程中还应考虑挡风玻璃的影响。本文的第一点是利用模型匹配的方法建立一个准确的有限元模型，该模型考虑到非线性材料和结构，以进行下一步的优化。虽然优化方法也能实现结构上的提升，它无法找到对结构固有的性能有重大影响的规律性结论。第二个创新是提出了灵敏度分析和模态应变能（MSE）指示相结合的方法。该方法不仅找到了特定的弱结构，而且总结了整体刚度失配特征和弱局部结构破坏整体结构平衡的观点。这些结论为进一步改进提供了依据。低频振动和噪声由于其波长长、穿透能力强，是解决低频振动和噪声的难题。作为第三个创新点，本文通过三维声子晶体模拟来优化结构的低频噪声。包括以上三个关键点的综合方法在抑制车辆低频振动和噪声方面具有非常好的效果。该方法也适用于其他复杂结构的仿真和优化。