Fatigue lives of short fiber reinforced thermoplastics parts

The fatigue lives of two different parts (made of short glass fiber reinforced Copolyamide) were investigated. The first one was a 150 mm by 10 mm by 4 mm coupon with a 2 mm hole at the center. The second one was an automotive gear shift link. The fiber orientations and the stresses inside these parts were calculated, respectively, by the commercial softwares C-Mold and by ABAQUS. The fatigue lives under different cyclic loads were measured; they were also estimated by a model based on the Generalized Miner's Rule, the results of C-Mold and ABAQUS, and the S-N data generated as part of this study [1,2]. Comparisons between the measured and estimated (by the model) fatigue lives are in reasonable agreement, indicating that the procedure employed is a useful tool for estimating the fatigue lives of parts made of short fiber reinforced thermoplastics.