Influence of Core on Face/Core Debond Toughness

The influence of mechanical properties and fracture toughness of the core on debond fracture toughness of foam core sandwich has been examined. It was found that the fracture toughness for debonding was larger than the core toughness. The observed difference between core fracture toughness and face/core debonding toughness was analyzed using plastic zone size and mode mixity arguments. The difference in toughness can not be explained by plastic zone size and mode mixity effects. It is possible that the core displays a gradient in properties and fracture resistance, and anisotropic behavior which might explain the difference in toughness.