A study of Fracture Mechanisms of Short Fiber Reinforced PET by Acoustic Emission Method. Effects of Notch Length and Fiber Content.

Abstract

Effects of notch length and fiber content on the tensile fracture behavior of short fiber reinforced polyethylene terephthalate (FRPET) are studied using the acoustic emission (AE) method. The cumulative AE event count and the total AE energy increase with increases in the notch length. The total AE energy decreases with increases in the fiber content, but the cumulative AE event count has a maximum value at a fiber content by volume of 17.3%. The log-log plot of the relationship between the total AE energy and the stress intensity factor has two broken points at Kb and KC which correspond to the changes in failure mode, respectively. The ratios of Pb/Pmax are varied, and Pc/P<max> values are roughly constant at the various notch lengths and fiber contents, where the Pb and Pc are loads determined by Kb and Kc, and Pmax is the maximum load. The relationship between the damage state at the notch tip and the AE frequency spectrum determines the fracture mechanisms of FRPET at the applied loads of Pb/Pmax and Pc/Pmax.