Mechanical behaviors of composite auxetic structures under quasi-static compression and dynamic impact.

This paper presents a low-velocity impact study on two types of structures, namely (1) planar multi-cellular auxetic structures (AUS) composed of multiple re-entrant cell structures made of unidirectional carbon fiber reinforced composite (CFRP) laminate, and (2) sandwich CFRP-AUS structures (Al/CFRP-AUS), whereby the CFRP-AUS was sandwiched by aluminium plates. The experimental results reveal the mechanical behaviors of CFRP-AUS under quasi-static compression and drop hammer impact loading, and the mechanical behavior of Al/CFRP-AUS under drop impact loading. The energy absorption of the CFRP-AUS associated with quasi-static compression is greater than that associated with drop hammer impact, which is consistent with the observed differences in failure modes. The impact energy absorption capacity of the Al/CFRP-AUS is slightly higher than that of the CFRP-AUS due to the interaction between the plates and the AUS. The corresponding finite element analysis was performed and the drop hammer impact of the multi-layered CFRP-AUS was predicted. In conclusion, the CFRP-AUS structures have good energy absorption capacity during impact loading, and the known complex mechanical behaviors of deformation, failure and contact can provide guidance for the design of energy absorption box and bumper in engineering application. • The multi-cell re-entrant structure and its sandwich structure with auxetic effect were prepared base on laminated CFRP. • The impact responses under quasi-static and dynamic impact loading were observed though experiments and FEA. • A possible lightweight anti-impact functional structure with meta-mechanical properties was reported. [ABSTRACT FROM AUTHOR]