FEM/BEM法振动板减振降噪优化设计

Study of Vibration and Noise Reduction by Minimizing Vibration Velocity for Plate Based on FEM/BEM

振动板的减振降噪设计是相关工程中结构设计的重要内容之一，优化设计可在设计阶段通过对设计模型的定量修改获得理想的减振降噪效果．基于有限元直接法计算了一两端固支矩形平板的频率响应，以板局部厚度为设计变量，以振动板各节点振动速度最小化为目标，建立了减小振动速度的优化模型，用可行方向法对一简支矩形板在1—200Hz的振动实施了优化；用间接边界元法对振动板在优化前、后的声学进行数值分析，以比较振动优化的降噪效果．实例结果表明，优化设计通过对结构重量的重新分布可在结构重量相对不变的情况下，在一较宽频段内均得到减振降噪效果．

TO reduce vibration and noise, frequency response is carried out by using FEM direct method, and the velocity sensitivity with respect to plate local thickness as design variables are computed for a plate. Optimization model is constructed to minimize velocities at all nodes and multi-frequencies. The optimization of the plate is performed by feasible direction method within the frequency of 1 - 200 Hz, and the acoustic radiation feature is determined by using BEM for both optimization and non-optimization. Results show that the optimization design of weight redistribution has an remarkable efficiency on vibration and noise reduction without weight change.