Mechanical properties of sandwich panels with perforated foam cores

Mechanical properties of sandwich panels employing E-glass/polyester face sheets bonded to a perforated foam core are evaluated and compared to sandwich panels fabricated with conventional plain sheet cores. Through-thickness compression testing, plate shear, face-core fracture toughness and weight measurements after infusion are used to evaluate the performance of both core configurations in sandwich panels. The influence of full and partial filling of the perforations with resin is also discussed based on experimental results and finite element analysis. It is found that complete filling of the core perforations with resin provide increased compression properties to the sandwich, at the expense of about 30% weight gain in the panel. Crack may be temporarily arrested when it meets a resin filled perforation, but this localized arrest is minor and does not significantly increase the global fracture toughness of the face-core interface. Partial resin filling of the perforations causes stress concentrations which significantly decrease the mechanical properties of the sandwich structure.