Revisit of compact Mode II crack specimen: Analysis and fracture interpretation

Analysis and fracture interpretation (using the strain energy density criterion) of Compact Shear specimen for Mode II fracture testing of materials is presented in the paper. Two approaches are used. One is based on singular integral equations for the problem of the interaction of two parallel cracks under Mode II loading corresponding to the loading in the Compact Shear specimen (CS specimen). Approximate analytical formulas for the stress intensity factors at the crack tips are derived. A numerical calculation using Gauss-quadrature formulae for the corresponding integral equations is presented. The influence of geometry of the problem on the stress intensity factors and on the angles of the initial propagation direction of the cracks is investigated. The other approach is Finite Element Method implemented in FRANC2D/L code. Numerical analysis was done for plain strain conditions. Different geometries of the specimen are considered for two models of the CS specimen and compared with results available in the literature. Analytical and FEM calculations are also compared and discussed.