On the compliance and energy release rate of generically-unified beam-type fracture specimens

摘要

A unified approach is proposed to evaluate the compliance and energy release rate (ERR) of generic beam-type interface fracture specimens. Based on a sub-layer Timoshenko beam theory, the classic composite (rigid joint), shear deformable (semi-rigid joint), and interface deformable (flexible joint) bi-layer beam models are revisited, from which the compliance and ERR of the generic beam-type fracture specimens are determined. According to specific combinations of loading conditions and material properties of each sub-layer, the generic fracture specimens are reduced to the conventional fracture specimens for actual applications. The effects of the crack tip deformation on the ERR of the interface crack are compared among the three different joint models, from which the evolving accuracy of the joint models to the ERR predictions of beam-type fracture specimens is manifested. The derived explicit formulas and improved solution for the compliance and ERR of the common beam-type fracture specimens can be effectively used to reduce data in interface fracture experiments and increase accuracy of fracture toughness evaluation of dissimilar material interfaces.