Modeling and analysis of the high-velocity impact resistance of composite butterfly-shaped honeycomb sandwich panels with shear-stiffening material

The high-velocity impact resistance of composite butterfly-shaped honeycomb sandwich panels (CBSHSPs) with flocculated fiber-reinforced shear-stiffening material (SSM) is investigated. Originally, two finite element models of the SSM-CBSHSP structure are developed using the full modeling method (FMM) and the equivalent modeling method (EMM) based on ABAQUS software to predict the high-velocity impact behaviors, respectively. In the FMM, the damage and failure of the butterfly-shaped honeycomb core and SSM are considered by the Besant failure criterion and the Christensen failure criterion, respectively, in which the strain rate effect is taken into account. In contrast, in the EMM, the Hamiltonian equivalence theory is employed to determine the equivalent Young's modulus and Poisson's ratio of the equivalent core, and the modified Christensen failure criterion is proposed to assess its failure penetration by a high-velocity impact projectile. Furthermore, specimens of SSM-CBSHSP with unfilled SSM, filled SSM, and filled flocculated fiber-reinforced SSM are prepared. Experimental investigations with varying initial impact velocities are also performed on these specimens to validate the developed models and assess the impact resistance. Finally, the influences of critical parameters on the impact resistance of the studied structure are analyzed and discussed, yielding several practical conclusions for the manufacturing and optimization of such sandwich panels.