Experimental Study of Debonded Sandwich Panels under Compressive Loading

Abstract

An experimental study of the in-plane compression failure of sandwich panels consisting of glass/epoxy face sheets over a range of PVC foam cores (H45, H100, and H200) and a balsa wood core containing one or two circular or square interfacial debonds is conducted. For the great majority of the specimens, failure occurred by local buckling of the debonded face sheet followed by rapid debond growth towards the panel edges, perpendicular to the applied load. Panels with the largest debond (10 cm diameter or 9 cm length) displayed some post-buckling strength. Examination of the face and core failure surfaces after total separation showed that the tendency for interface (core/resin) failure increases with increasing core density. It was found that the compression strength strongly decreases with decreasing core stiffness and increasing debond size. The compression strength of panels with H45 core decreased with reduced core thickness. Failure loads for panels with symmetric debonds at both face/core interfaces were practically the same as those for panels containing a single debond. Panels with square debonds failed at lower loads than those with circular debonds of the same area. Circular debonds of 50 mm diameter and square debonds of 45 mm length set the threshold for debond failure of the panels considered here.