An Evaluation of the Compact Shear Specimen for Mixed Mode Fracture Studies

Abstract

A compact shear specimen configuration, consisting of three legs with the outer two loaded axially in a direction opposite to the inner one, has been used for several mixed-mode fracture studies. From a detailed computer analysis of this specimen, it is shown that the loading boundary conditions play an extremely important role in determining the state of stress at the crack tip. By simply changing the flexibility of the loading fixture, the specimen can be subjected to a range of mixed mode conditions from almost all Mode I to virtually pure Mode II. Data of other researchers are reviewed in light of this finding. It is shown that by applying loads obliquely to the outer legs pure Mode I loading may also be obtained with this specimen.