Deformation rate dependence of work of fracture parameters in polybutyleneterephthalate (PBT)

Essential work of fracture (EWF) analysis was used to study the effect of l oading rate (v = 2, 5, 25 and 50 mm/min) on fracture toughness of PET film of thicknesses 0.175, 0.275, 0.375 and 0.5 mm. Using single edge notched te nsion (SENT) specimens, it was found that the specific essential work of fr acture, w(e), increases slightly with increasing loading rate but Within th e specified range of loading rate, it showed no significant variation with respect to thickness. The specific non-essential work of fracture, beta w(p ), decreased with increasing rate and increasing thickness.