NOTCHED STRENGTH OF LONG-FIBER AND SHORT-FIBER REINFORCED POLYAMIDE

A test programme has been conducted to evaluate the tensile strength of injection moulded plates with machined and moulded-in notches. The long-fibre compound, Verton, is consistently less notch sensitive than the short-fibre compound, Maranyl. Moulded-in holes appear to have several advantages over machined holes: they yield up to 25% higher strength and less sensitivity to plate thickness and injection speed. Five existing laminate fracture models are applied to the machine-notched plates; the average stress criterion and the damage zone model give the most accurate predictions.