Flexed plate impact testing of poly(ether sulphone) Part III Flow geometry effects

Tests on various sample shapes moulded from poly(ether sulphone) show that the response to an excess energy impact may be brittle failure, ductile failure or mixed mode failure, depending on the geometrical features and the associated flow geometries at or near the point of impact. Flow irregularities and local anisotropies caused by the overall flow geometry can be as detrimental to the toughness as conventional stress concentrators are. The results, which are unlikely to be unique to poly(ether sulphone), imply that the procedures currently followed for the evaluation of impact resistance are generally insufficient for their purpose since materials are likely to differ in their susceptibility to embrittlement.