Abstract
A purpose of this study is to evaluate the effect of the interfacial crack suppression and the crack growth behavior when resin materials with high formability is applied to a crack arrester as replacement of a conventional CFRP material. As the crack arrester is a structural element to suppress interfacial crack by the load redistribution between the leading edge of the arrester and foam core material near the crack tip, the effect of an elastic modulus and a high thermal expansion rate of the resin material should be evaluated. In this study, the effect of the resin arrester on the crack suppression was estimated through the DCB tests and relating numerical analyses. As for the arrester materials, the Loctite HC 9872.1 Kio Aero of Henkel was selected. Two kinds of test specimen, the test specimen with the basic type arrester and with the modified type arrester, were fabricated and prepared for the DCB tests. The DCB tests were conducted using these two types of test specimens. Through the DCB tests, the comparable crack suppression effect to that of the CFRP arrester were confirmed despite the relatively low elastic modulus and the high thermal expansion rate. The numerical analyses indicated that the thermal shrinkage of the resin material of the crack arrester enhanced the crack suppression effect due to the crack closing effect by the thermal deformation. It was also found through the microscopic observation and relating numerical analyses that the resin material impregnated into the interlaminar of the surface skin from the resin arrester increased the apparent energy release rate at the crack tip. Through this study, useful findings were obtained when the resin arrester would be applied to aircraft structures.
