Frequency-dependent damped vibrations of multifunctional foam plates sandwiched and integrated by composite faces

Abstract

This paper investigates damped vibrational behavior of a lightweight sandwich plate subjected to a periodic load within a limited time. The lightweight sandwich structure includes a thick polymeric porous core with either functionally graded or uniformly distributions of voids which is sandwiched by two thin layers of laminate composites. To investigate the effect of void distribution properly, the same void volume fraction has been considered while different types of core have been analyzed. Using the first-order shear deformation theory of plates, the governing equations for the free and forced vibrations have been developed. By involving structural damping, these equations which are able to treat thin to moderately thick plates have been solved by developing a computationally cost-effective finite element approach. An extensive sensitivity analysis has been performed to examine the effects of fiber orientation in composite layers, void's volume and dispersion in core, and geometrical dimensions on the vibrational behavior of such porous composite sandwich plates (PCSPs). The results show that the use of foam in PCSPs considerably reduces the amplitude of vibrations and improves the fundamental frequency. Furthermore, it was found that the use of [45, -45](2) composite layers offers PCSPs with the highest natural frequency and the lowest amplitude of vibrations.