Font Size: 

A novel crack specimen has been designed to study brittle fracture in mode IIloading. The test specimen is simulated using finite element analysis and the crack tipparameters KII and T are calculated. Both tensile and compressive loading can be applied tothe specimen. For tensile loading where the specimen is subjected to positive shear, the Tstressis positive. Whereas T is negative for compressive loading, that is when the specimenis subjected to negative shear. Fracture tests are carried out on several specimens made ofPMMA. The Mode II fracture toughness is determined for both tensile loading (positive Tspecimens) and compressive loading (negative T specimens). Experimental results showthat mode II fracture toughness for negative T specimens are significantly larger than thosefor positive T specimens.