Experimental investigation of interfacial fracture behavior in foam core sandwich beams with visco-elastic adhesive interface

Interfacial toughness as well as toughness enhancement and long term interfacial fracture behavior in sandwich beams were experimentally examined. The interfacial toughness was enhanced by inserting a chopped glass fiber mat at the interface during the fabrication process. Robust interfacial load capacity and improved toughness were obtained by the method. The long term interfacial fracture behavior presents the characteristics of the three-parameter solid (standard solid) model. The results of the long term fracture tests show a significant increment in crack opening displacement and nominal stress intensity factors. It indicates that during the process of structural design and analysis the interfacial fracture resistance may be overestimated without taking the visco-elastic effect of the materials of the structure into consideration.