Fatigue performance of wind turbine rotor blade epoxy adhesives

Abstract

Structural epoxy adhesives modified with short-glass fiber and core-shell rubber particles are used in wind turbine rotor blade assembly. This work aims at investigating the hybrid effects of these adhesives on their fatigue performance. The effect of ASTM D638-22 Type I and Type II specimen geometry on fatigue life is also examined. Competing damage mechanisms are identified with scanning electron microscopic images. These mechanisms result in similar S-N curve slopes for the examined adhesives when Type II specimens are used. All adhesive materials can endure at least 106 cycles at the maximum applied stresses of nearly 35% of their static strength, confirming the strength-life equal rank assumption. Nevertheless, Type I specimens exhibit an increased S-N curve slope of 7.32%–15.56% than Type II specimens.

Keywords

• Fatigue
• Composites
• Adhesives
• Toughening
• Geometry effect
• Failure analysis