四边简支双曲率蜂窝夹层薄壳自由振动分析

Free vibration analysis of a double-curvature honeycomb sandwich thin shell with simply supported boundaries

基于Reddy三阶剪切理论,研究了四边简支双曲率蜂窝夹层薄壳的自由振动,以及结构参数对蜂窝夹层薄壳固有频率的影响。将由六边形胞元组成的蜂窝芯层等效为一正交异性层,其等效弹性参数由修正后的Gibson公式得到,应用Reddy三阶剪切理论和Hamilton变分原理推导出四边简支条件下双曲率蜂窝夹层薄壳的频率方程。具体算例表明,采用Reddy三阶剪切理论计算的固有频率精度较高;双曲率蜂窝夹层薄壳的曲率、厚度比及胞元角度对蜂窝夹层壳固有频率有不同程度的影响,其中蜂窝夹层薄壳的固有频率随曲率的增大而增大,随厚度比的增大呈波动变化,随胞元角度的增大而减小。

Free vibration of a double-curvature honeycomb sandwich thin shell with simply supported boundary conditions was investigated by using Reddy＇s third-order theory and the influences of the structural parameters on its natural frequencies were also studied.Here,the honeycomb core of hexagonal cells was modeled as a layer of orthotropic material with physical and mechanical properties determined using the corrected Gibson＇s formula.The frequency equation of the honeycomb sandwich thin shell was deduced with Reddy＇s third-order theory and Hamilton＇s variational principle.The results indicated that Reddy＇s third-order theory has adequate accuracy to compute the natural vibration frequencies of the double-curvature honeycomb sandwich thin shell;the effects of curvature,thickness ratio and cell angle on the natural vibration frequencies of the double-curvature honeycomb sandwich thin shell are different,the natural frequencies of the honeycomb sandwich thin shell increase with increase in curvature,fluctuate with increase in thickness ratio and decrease with increase in cell angle.