Impact and Damage Prediction of Sandwich Beams with Flexible Core Considering Arbitrary Boundary Effects

In this study, a higher-order impact sandwich beam model is presented to simulate the response of a soft-core sandwich beam subjected to a foreign object impact. The effects of asymmetric lay-up of the sandwich and arbitrary boundary conditions are accounted for in the analysis, and the solution is obtained by employing a finite difference method (FDM). A static and free vibration problem of sandwich beams is first solved, and the results are validated by comparing with the numerical finite element predictions of ABAQUS. The validity of the impact response is then examined using the LS-DYNA model. The contact force and deflection history as well as the propagation of axial, shear, and transverse normal stresses in the sandwich beams during the impact are analyzed. The local effect at the boundary and the loading location is captured by the present model, and the influences of boundary conditions (i.e., the top face sheet free and the bottom pin—pin supported versus both the top and bottom face sheets clamped) and the load spreading process on the impact behavior are discussed. The calculated stresses under the foreign object impact are further incorporated with the failure criteria to assess the failure location, time, and mode in the sandwich beams. The damage induced by the impact process is predicted and comprehensively compared with the experimental results. The higher-order impact model of sandwich beams with the FDM provides accurate predictions of the generated stresses and induced damage, and it can be used effectively in design analysis of anti-impact structures made of sandwiches.