Low Velocity Impact Response of Preloaded CFRP/Aluminum Honeycomb Sandwich Plate

In practical engineering applications, composite sandwich structures are always in preload condition before subjected to possible low velocity impact (LVI) occasions. In the present work, a nonlinear finite element (FE) model is developed to study the mechanical behavior of preloaded aluminum honeycomb sandwich structures with carbon fiber reinforced plastic (CFRP) face sheets under LVI. Johnson–Cook model is adopted to identify the damage of aluminum honeycomb core; a progressive damage constitutive model and a bilinear cohesive zone model are employed to capture the intra-laminar response and inter-laminar delamination of CFRP face sheets. The effects of preload condition and impact position on the LVI resistance of sandwich plate are analyzed in detail. Besides, the energy absorption properties and damage characteristics of sandwich plate during the impact are examined. The results show that tension preload reduces the damage area of the core and the compression preload causes the sandwich plate to bend and deform when it is impacted. The effect of impact position on the damage of sandwich plate shows obvious asymmetry. This work provides a transferable technique for numerical analysis of LVI issues of other composite structures under preloading.