Dynamic Response of Composite Sandwich Beams With Arbitrary Functionally Graded Cores Subjected to Low-Velocity Impact

Abstract

Using an improved higher-order sandwich panel theory (IHSAPT), the dynamic response of a sandwich beam with arbitrary cores (foam or functionally graded materials) subjected to single impact at arbitrary impacted face sheet and arbitrary locations is studied. The formulation uses the first-order shear deformation theory for the composite face sheets and a polynomial description of the displacements fields in the core, which is based on the displacement field of the second Frostig's model. The unknowns are the coefficients of these polynomials in addition to the displacements of the various face sheets. It is assumed that the impactor impacted normally and simultaneously over the top or bottom face sheets. The impact force between the impacted face sheet and the impactor is treated as the internal force of the system and in this study, for the first time, in order to simulate the impact phenomena, two models are presented: first, the linearized spring–mass model with two degrees of freedom (simply called TDOF), which can be solved by a new analytical method; second, the modified Hertz's model, which uses the perfect form of contact law (perfect model). An impact problem of sandwich beam is first solved and the results obtained from TDOF and perfect models are validated by comparing them with the analytical and numerical results published in the literature and also together. The agreement between the results is quite good. Then, the effect of various types of FGM function and its power and core to beam thickness ratio on the dynamic behavior of sandwich beam are studied.