Fatigue‐life prediction of glass fiber reinforced Polypropylene and Polyamides composite materials based on the three‐parameter Weibull distribution

Abstract At present, there is limited literature available on the fatigue life estimation of glass fiber fabric‐reinforced thermoplastic polymer composites. This study performed constant amplitude fatigue testing to assess the fatigue life of twill‐woven glass fiber‐reinforced thermoplastic composites made from polypropylene (PP) and polyamide (PA) under four different stress levels (70%, 60%, 50%, and 40% of the ultimate tensile strength) with a stress ratio of 0.1. The fatigue life of the specimens was analyzed statistically using two‐parameter and three‐parameter Weibull distribution functions. Linear regression analysis results demonstrates a strong correlation between the independent and dependent variables in the two‐parameter Weibull analysis (correlation coefficient above 0.80), with an even better correlation observed in the three‐parameter analysis (correlation coefficient above 0.94). Based on the parameters derived from the Weibull distribution, the fatigue life of the laminates at varying survival rates has been evaluated. A P‐S‐N fatigue life prediction model has been developed from these results to account for different failure rates. Comparison with the tensile fatigue performance data of fiber‐reinforced polymer composites from the literature indicated that glass fiber‐reinforced thermoplastic composites exhibit excellent fatigue resistance. Highlights The fatigue of twill‐weave glass fiber reinforced PA/PP was investigated. The fatigue life was analyzed using three‐parameter Weibull distribution functions. A fatigue life prediction model was established based on the Weibull distribution function. The P‐S‐N fatigue life prediction model provides a reference for material design.