Manufacturing and mechanical testing of curved sandwich beams with zero‐Poisson's ratio honeycomb cores

Abstract

AbstractIn this research, free curling property of the over‐expanded honeycomb (OH) with zero Poisson's ratio was utilized to design and manufacture curved carbon fiber‐reinforced composite (CFRC) sandwich beams by hot compression molding technique and co‐curing process. Three‐point bending experiments were conducted to reveal the failure mechanism of these OH‐based curved sandwich beams with various curvatures. The results reveal that in this research no matter what the curvature is, the shearing fracture of the OH core controls the initial failure of the curved structure, which is followed by upper skin fracture, lower skin delamination and fracture. With the increase of curvature, the ultimate bearing capacity and flexural rigidity of the curved beams will increase. No debonding was observed in the experiments.Highlights Curved sandwich beams with zero‐Poisson's ratio honeycomb‐core was designed. Deformation process from arc, flattening to anti‐arc was revealed by testing. Strength of curved sandwich beams depends on shear strength of the honeycomb. Beams with smaller curvature have greater bearing capacity and stiffness.