Impact properties of injection molded glass fiber/polyamide-6 composites: effect of testing parameters

Abstract

Reported data on impact properties show that wide discrepancies exist, although the same grade of materials was being used. In this article, we report some testing condition-property relationships of injection molded glass-fiber/polyamide-6 composites. It was found that an increase in specimen size/geometry leads to an increase in fracture energy and peak load; however, critical strain energy release rate and critical stress intensity factor decrease. Increase in impactor velocity, fracture energy, and peak load are all in mixed mode (increase and decrease). Similar to inconsistency obtained in fracture energy, critical strain energy release rate is also in mixed mode. However, critical stress intensity factor is marginally increased. Increases in impactor load weight and fracture energy at all notch to depth ratios are sensibly increased; however, critical strain energy release rate is marginally decreased at lower V_f and sensibly increased at higher fiber loading. With an increase in impactor load weight, changes in peak load are also in mixed mode, whereas critical stress intensity factor is marginally decreased.