粘弹性芯材复合材料夹芯板的自由振动分析

Analysis of free vibration of composite sandwich with viscoelastic core layer

基于Kelvin粘弹性芯材本构特征模型,推导了复合材料夹芯板的动力学控制方程,给出了四边简支正交对称铺层表层夹芯板的固有频率和结构损耗因子解析解,并将解析解与有限元计算结果进行了对比验证。探讨了阻尼层参数变化对结构固有自由振动特性的影响。分析结果表明:增加芯材厚度能有效地提高结构固有频率和损耗因子;结构的有阻尼自振频率受损耗因子影响较小,但其损耗因子随着芯材材料损耗因子的增加而增加;结构的固有频率随着芯材剪切模量的增加而增加,增幅逐渐减小;随着芯材剪切模量的增加,结构的损耗因子先增加后减小,芯材剪切模量设计存在最佳值;结构尺寸增加,芯材剪切模量最佳值逐渐减小。

Based on Kelvin model characterized by viscoelastic core constitution, the derivation of a set of dynamical equations for rectangular composite sandwich plate was conducted to present the analytic solutions of natural frequencies and modal loss factors of a composite sandwich plate with symmetric and orthotropic face layers depending on the simple support boundary conditions. The comparison of natural frequencies with Abaqus FEM validated the theoretical model. The effects of the viscoelastic core parameter on the dynamic performance of the composite sandwich plate were discussed. The re- sults show that the natural frequencies and modal loss factors can be effectively improved as the thick- ness of core material is increased, that the modal loss factors increase markedly when the loss factors of the core material increase with less influence on the natural frequencies with damping, and that the modal loss factors tend to go from ascent to descent with the increase of the modulus of the core mate- rial, which reveals that there is an optimal value in the design of the core material shear modulus and that the optimal value decreases when the structural dimension increases.