移动荷载对周期加固壳波传播的影响

Effects of moving loads on wave propagation in periodic stiffened shell

基于Donnell-Mushtari薄壳理论,建立了均质壳体的轴对称径向波动微分方程,推导了周期加固壳在随荷载移动的动态坐标系下各胞元的动态刚度矩阵,进而利用传递矩阵法得到了相邻胞元间的传递矩阵,并计算了均质壳在移动荷载作用下的临界速度。根据Wolf算法,采用局部化因子分析了几何尺寸变化及其失谐对波传播及其局部化特性的影响。分析表明,与均质壳相比,周期加固壳扩展了临界速度值。结构的尺寸变化显著地影响速度通禁带的个数、宽度及其位置,可以通过调整结构的参数来改变波动的传播。失谐周期加固壳会出现波动局部化现象,随着失谐程度的增加,结构的波动局部化程度增强。分析结果对周期加固壳在移动荷载作用下的优化设计和振动控制研究提供了理论参考。

According to Donnell-Mushtari theory for thin shells,the differential equation governing the radial axi-symmetric vi-bration of the uniform shell is established.The dynamic stiffness matrix of each cell in the periodic stiffened shell is obtained in a coordinate system moving with the load and the transfer matrix between the adjacent cells is derived based on the transfer ma-trix method.A critical velocity of a uniform shell is investigated.The effects of geometric sizes and disorder on the wave prop-agation and localization characteristics of the ordered and disordered periodic stiffened shells are assessed from localization fac-tors according to the Wolf’s algorithm.The obtained results show that periodic stiffened shells expand the critical velocities. Geometric sizes have drastic effects on the numbers and widths as well as the locations of the velocity bands,so the characteris-tics of wave propagation in the structure can be altered by properly tuning structural parameters.The wave localization phe-nomenon occurs for the disordered periodic stiffened shell.As the level of disorder increases,the localization degree is strengthened.The investigation provides the basic guidelines for optimization design and vibration control in periodic stiffened structures.