Fibre Orientation at Notches and Fatigue Behaviour of Short Fibre Reinforced Polyamide

Fatigue strength of injection moulded short fibre reinforced polymer components depends upon fibre orientation with reference to the acting stresses. For the case of a short glass fibre reinforced (SGFR) polyamide 6, this dependence was expressed through a relationship derived from the Tsai-Hill criterion [1], with the strong assumption that fibres were parallel to each other. This relationship was verified for offaxis uniaxial tests on specimens extracted from injection moulded plates and assuming that mean fibre orientation coincided with the plate’s axis. Real parts display a more complex geometry, and their fatigue strength is influenced by other factors like weld lines [2] and notches [3,4]. No analysis of the local fibre orientation distribution was reported in these previously published papers.