Enhanced fatigue life in GFRP composites: A comparative study of wet lay-up versus vacuum assisted resin transfer molding for small-scale wind turbine blades

Abstract

Wet lay-up and vacuum-assisted resin transfer molding have been considered as the most popular and cost-effective manufacturing processes of E-glass fiber reinforced epoxy-based laminated composite, especially in the wind turbine blade manufacturing industry. This study compares the fatigue behavior of GFRP laminated composites manufactured via wet lay-up and vacuum-assisted resin transfer molding processes. Vacuum-assisted resin transfer molding samples exhibited 85% longer fatigue life at a stress level of 0.4 ultimate tensile strength compared to wet lay-up samples. The average ultimate tensile strength of vacuum-assisted resin transfer molding samples was 50% higher, with improved fatigue resistance due to enhanced fiber-matrix bonding. Scanning electron microscopy fracture analysis revealed improved fiber/matrix bonding in vacuum-assisted resin transfer molding fatigued samples, contributing to enhanced fatigue performance. These findings provide critical insights for wind turbine blade material selection and optimization. The results indicate that vacuum-assisted resin transfer molding composites sustain 4.5 more load cycles at lower stress levels, demonstrating superior fatigue performance for wind turbine blades.