Experimental and numerical investigation on fracture behavior of CTS specimen under I-II mixed mode loading

Experimental and numerical investigations are both performed to study the fracture behavior of CTS specimen of CP-Ti under I-II mixed mode loading. The results show that crack growth path and loading capability of CTS specimen are dependent on both loading angle and crack length. Or rather, crack length effect of CTS specimen on the loading capability and crack growth path (except for pure mode I) becomes more remarkable, as the component of mode I increases. Opening stress from mode I loading is the main reason, the applied mode (tensile and bending opening stress) of which is associated with the crack length of CTS specimen. It is due to the opening stress applied on the specimen, crack length effects on the transition from ductile to brittle fracture and plastic zone (except for pure mode I) ahead of crack tip are more obvious when the component of mode I is dominant, which also explain the results of loading capability and crack growth path (except for pure mode I) respectively. In addition, critical J-integrals J(c) are analyzed, the results show that constraint effect on J(c) of mode I dominant crack is much more remarkable than that of mode II dominant crack, which is also because of the applied style of opening stress on the specimen.