Effects of Interfacial Delaminations in Curved Sandwich Beams

The influence of face/core debonding on the structural integrity of curved sandwich beams subjected to opening bending moments has been examined experimentally. The sandwich beams consisted of glass/polyester faces over a PVC H30 foam core. Debonds of various sizes were implanted by inserting thin teflon sheets at the outer face/core interface in the curved region of the beam prior to processing. A test fixture for flexure testing of curved sandwich beams was designed and manufactured, and evaluated using homogeneous isotropic beams. The surface strains at the middle of the curve were recorded to examine the response. Buckling of the debonded face sheet occurred followed by face/core propagation of the debond. Strength reduction of the beams under opening moments due to face/core debonding was substantial.