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 (beta w(p)) in a very significant way. The plastic zone shape factor (beta) was found to be very sensitive to both the geometry and temperature. It was established that both w(e) and beta w(p) could be partitioned into components that are linked to yielding (i.e. w(e,y) and beta(y)w(p,y)) and necking/tearing (i.e. w(e,nt) and beta(nt)w(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 beta(y)w(p,y) and beta(nt)w(p,nt). (C) 1999 Kluwer Academic Publishers.