Fatigue Trends for Wind Blade Infusion Resins and Fabrics

Abstract

This paper presents recently expanded test data for resin infused glass fiber laminates of interest for wind turbine blades. The new static and fatigue data extend and clarify trends reported in References 3-7 for the relative performance of epoxy, vinyl ester and polyester resins, and various unidirectional (UD) and biaxial (±45) fabrics, and multidirectional (MD) combinations, in standard laminate tests. Significant resin, fabric and process interactions are identified and explored. A second part of the study involves characterizing the performance of the various fabrics and resins in the context of a recently developed complex structured coupon geometry including ply drops. This coupon provides a simplified approach to exploring the relative performance of blade materials in the context of the complex structural details typical of infused blades. This testing approach highlights the significance of resin toughness differences in a representation which can conveniently be applied to blade design as strain knockdown factors.