FRACTURE TOUGHNESS OF CORE SKIN INTERFACES OF SANDWICH MATERIALS

摘要

This paper investigates how damages in the form of core/skin delamination propagate. The results can be used to classify the resistance of materials against spread of this type of damage. They could also be used as a basis for deciding whether to repair a structure. Mode I fracture toughness data was measured for the interface between GRP skins and cores of PVC foam and balsa wood in sandwich beams. A new test method was developed. Depending on core material and interface quality, the cracks propagated in or close to the interface. Due to nonlinear behaviour observed in the tests, a special analysis procedure was used to provide the fracture toughness. When the crack propagates inside a PVC core (along the interface) this method gives G_(IC) values similar to published values for the core material.