Through-the-thickness z-pinning reinforcements to improve energy absorption capabilities of CFRP crash structures: numerical development

This study employs numerical methods to model through-the-thickness reinforcements in CFRP tubular structures under axial impact, investigating the influence of reinforcement configurations on crashworthiness performance. Experimental validation involves testing unpinned tubular structures to establish a baseline model. LS-DYNA finite element models simulate low-velocity axial impacts, incorporating energy-based tiebreak contacts or solid cohesive elements to describe interlaminar bridging. Through-the-thickness are introduced through a homogenous mesh system or locally refined mesh at pin locations. Various reinforced tube designs with different pin diameters and areal densities are examined to identify the optimal pinned design for crashworthiness. The research demonstrates numerically that pinning enhances crashworthiness performances in axial crushing of composite tubes.