On the use of an anti-symmetric four-point bend specimen for mode II fracture experiments

The edge-cracked beam specimen subjected to anti-symmetric four-point bend (ASFPB) loading has been conventionally used in the past for investigating the pure mode II fracture experiments in many engineering materials. However, it is shown through finite element analysis that the ASFPB specimen sometimes fails to produce pure mode II conditions. For anti-symmetric loads applied close to the crack line, there are considerable effects from K-I and T-stress in the ASFPB specimen. Pure mode II is provided only when the applied loads are sufficiently far from the crack plane.