Residual Compressive Strength of Aluminum Honeycomb Sandwich Structures with CFRP Face Sheets after Low-velocity Impact

Composite sandwich structures are sensitive to low velocity impact (LVI) occasions and the induced damage significantly reduces the residual load-bearing capacity of material structures. In this work, a nonlinear finite element (FE) model is proposed to investigate the buckling and damage behavior of aluminum honeycomb sandwich structures with CFRP face sheets under compression-after-impact (CAI). Johnson-Cook model is applied to identify the damage of aluminum honeycomb core; cohesive elements governed by bilinear traction-separation constitutive model are implemented to describe the inter-laminar delamination induced by LVI and CAI. The numerical results are in good agreement with the available experimental data, which verifies the effectiveness of the proposed FE model. The effects of impact energy and core parameters on the impact performance and residual compressive strength of sandwich structures are analyzed in detail and the energy absorption properties during the corresponding loading are examined. The numerical results show that slight impact damage can also greatly reduce the CAI strength. Besides, the parameters of core have an important influence on the stiffness and CAI strength of sandwich panel.