The effect of the testing conditions on the fracture mechanics characteristics of short glass fibre reinforced polyamide

The aim of the work was to investigate the influence of the testing conditions (i.e., loading rate, crack length, mechanical damping) on the fracture mechanics characteristics of a short glass fibre reinforced polyamide. Instrumented Charpy impact experiments were carried out on pre-cracked specimens of PA6.6 polyamide material containing a different quantity of short glass fibre reinforcement. In the case of 1 m/s loading rate, the evaluation procedure for static tests could be applied for determination of dynamic fracture toughness (KId) and strain energy release rate (GId). In the case of 3.7 m/s loading rate, the dynamic key-curve method was used to determine KId, and the time to fracture was obtained by electric-emission measurement.