Factors affecting work of fracture of uPVC film

Essential work of fracture (EWF) approach was used to evaluate the fracture toughness of uPVC film. It was found that the specific essential work of fracture, (w_e) is independent of specimen width, specimen gauge length, loading rate and test temperature, but dependent on the geometry of the test specimens. Test temperature and geometry were the only testing parameters affecting the specific non-essential work of fracture (w_p) in a very significant way. The plastic zone shape factor () was found to be very sensitive to both the geometry and temperature. It was established that both w_e and w_p could be partitioned into components that are linked to yielding (i.e. w_e,y and _yw_p,y) and necking/tearing (i.e. w_e,nt and _ntw_p,nt) processes. The only testing parameter that affected w_e,y was test temperature, whereas w_e,nt was affected by test temperature as well as geometry. All testing parameters used in this study affected the values of _yw_p,y and _ntw_p,nt.