Experiment and analysis on free vibration of sandwich plates based on an alternative sinusoidal global-local theory

This study presents an alternative and easy-to-use model to produce accurately higher-order frequencies of composite and sandwich plates. The proposed model only contains the independent displacement variables, and compatible conditions of displacements and stresses at interfaces of adjacent layers can be met beforehand. Exact solution is firstly utilized to appraise capability of present model. Subsequently, a triangular element based on the proposed model has been also established for dynamic analysis of sandwich plates with complex boundary conditions, where the refined element approach is utilized to conquer compatible requirement of first derivatives of deflection at shared edges of adjacent elements. To strictly evaluate the models, tests of natural frequencies for sandwich plates composed of aluminium face sheets and PMI foam core are carried out, which are less reported in literature. Compared to testing data, the good performance of the proposed model can be illustrated. This work can also demonstrate that compatible conditions of transverse shear stresses at interfaces have a significant impact on accurate prediction of higher-order frequencies of composite and sandwich plates, but model fulfilling compatible conditions of stresses might also fail to produce precisely higher order frequencies.

Automated summary

This study proposes an alternative model for accurately predicting higher-order frequencies of composite and sandwich plates, demonstrating its effectiveness through tests. It is found that compatible conditions of transverse shear stresses at interfaces play a crucial role in predicting higher-order frequencies accurately.