Infusible Thermoplastic Composites for Wind Turbine Blade Manufacturing: Fatigue Life of Thermoplastic Laminates under Ambient and Low‐Temperature Conditions

Abstract

Traditionally, thermoset resins such as polyesters (PE) and epoxies are used as the polymer matrix for construction of wind turbine blades. However, concern about their end‐of‐life treatment garners interest to use thermoplastics for increased recyclability. However, the high viscosity of molten thermoplastics inhibits their use in manufacturing wind turbine blades with injection or compression molding. A recently developed, infusible, reactive thermoplastic resin overcomes this technological barrier. Toward verifying that this recyclable resin is suitable for use in wind turbine blades, a dataset of R = 0.1 and R = 10 fatigue data for glass fiber–reinforced acrylic composites is provided and equal fatigue life to industry standard epoxy and unsaturated PE resin systems is demonstrated. Specifically, R = 0.1 fatigue data for acrylic composites at room temperature and −30 °C for verification of low‐temperature performance are tabulated. To elucidate failure mechanisms, in situ mechanical testing with X‐ray computed tomography demonstrates that damage accumulation occurs by crack propagation along the fiber–matrix interface under cyclic loading. Infrared (IR) thermography predicts failure points in composites specimens with porosity defects introduced from nonideal manufacturing processes. Furthermore, these manufacturing defects are shown to compromise the fatigue life of the acrylic laminates by an order of magnitude.

RETRACTED: Mechanical Properties Study on Sandwich Composites of Glass Fiber Reinforced Plastics (GFRP) Using Liquid Thermoplastic Resin, Elium®: Preliminary Experiments

“…GF/PVC/E GF/PET/ELIUM, and GF/PET/EPOXY sandwich structures observed loads of 1156 N, and 845 N, equal to 206, 165, and 159 MPa, respectively. Cousins et al measured flexural strengths in the Elium-based composite laminates (1006 MPa) than the based reference material (809 MPa) [64]. Davies and Arhant reported flexural stren 703 MPa and 606 MPa for glass fiber-reinforced elium and epoxy composites w volume fractions of 52 and 53%, respectively [65].…”

How to Repair the Next Generation of Wind Turbine Blades

“…Elium has a relatively low glass transition temperature, shows mechanical properties close to those of epoxies, and can be used with the same processing equipment. Murray and colleagues [36] and Cousin et al [37] tested coupons and vacuum-assisted resin transfer molding (VARTM) to produce a blade spar cap made with Elium resin. They observed a fatigue life comparable or longer for thermoplastic composites than for the usual epoxy composites and with comparable elastic properties.…”