Dynamic instability of a three-layered soft-cored sandwich beam on elastic foundation

The purpose of the present work was to study the dynamic instability of a three-layered sandwich beam with flexible core and simply supported boundary conditions subjected to a periodic axial load resting on elastic foundation. A higher-order theory was used for analysis of sandwich beams. In this theory, the classical theory was used for the face sheets and quadratic and cubic functions were assumed for the core, respectively. The elastic foundation was modeled as Winkler’s type. The dynamic instability regions were investigated for simply supported conditions by Bolotin’s method. The governing equations derived by the principle of minimum potential energy. The results showed that the responses of the dynamic instability of the system were influenced by the excitation frequency, the foundation modulus and the angle of the plies. Comparison of the present results with the published results in the literature for the special case confirmed the accuracy of the proposed theory.