Low-velocity impact response of composite sandwich structure with grid–honeycomb hybrid core

Abstract

Grid structures have great potential for engineering application, inspired by the leaf texture, the rectangular grid is innovatively added to the honeycomb to form the grid-honeycomb hybrid core. The low-velocity impact response of the composite sandwich structure with grid–honeycomb hybrid core was investigated by experimental and numerical simulation. Low-velocity impact tests with 30 J energy were conducted of the sandwich panel to analyze the mechanical response and damage morphology at typical locations (intersection, rib, and center). The results show that the impact resistance at the intersection was the strongest, the peak load, damage threshold load, and initial stiffness at the intersection were 14.74%, 15.54%, and 16.06% higher, and the maximum displacement and residual displacement were 12.09% and 33.71% lower, respectively than those at the rib, and the center was the weakest. Compared with honeycomb sandwich panel, the impact resistance of unit mass at the intersection and rib was stronger and the internal damage was smaller. In addition, the parametric study of the structural parameters of sandwich panel was conducted. The grid thickness had a significant effect on the impact resistance, while the effects of honeycomb wall thickness and honeycomb unit cell diameter were smaller and had almost no effect on initial stiffness and energy absorption. Finally, the impact resistance efficiency analysis was performed to obtain the optimal design area of structural parameters to provide design guidance.