Effect of severe thermo-oxidative aging on the mechanical behavior and fatigue durability of short glass fiber reinforced PA6/6.6

The work deals with the fatigue lifetime estimation of Short Fiber Reinforced Thermoplastics (SFRP), a focus on conjugated effects thermal aging. Two materials containing 35% (V35) and 50% (V50) weight ratio short glass fibers were aged for 500 h at 200°C in air compared to same Dry-As-Molded (DAM) state. Monotonic tests performed samples machined out injected plates cut along three different orientations injection one (0°, 45°, 90°) order capture anisotropy skin-core microstructure, classical SFRP. tensile evidenced stiffening embrittlement Polyamide matrix reported literature, nevertheless an acuity depending fiber orientation. Stress-controlled constant amplitude, frequency (10 Hz), temperature (200°C) stress R = 0.1. curves V35 are more affected by aging than those V50 material. combined results from mean strain evolutions SEM observations confirmed that initiation approach was still valid composites. Several criteria, among most recently evaluated this database. effect cyclic evolution Fatigue Indicator Parameters (FIP) involved criteria analyzed preliminarily. For present conditions, best unaged (i.e creep energy-based ones) shown be materials. Finally, ability predict composites identification criterion state evaluated.