Prediction of Cure‐Induced Wrinkles Aimed at the Manufacturing of Large Wind Turbine Blades

ABSTRACT This work uses predictive modeling to study the phenomenon of cure‐induced wrinkles based on validated experimental model behavior. The mechanisms that govern the occurrence are studied with emphasis on the need for thermal gradients, causing a variation in thermal expansion and build‐up of stiffness across a large monolithic composite laminate to create cure‐induced wrinkles. The appearance of wrinkles was evaluated based on the undulated region's maximum amplitude, angle, and wavelength. The angle is especially important for understanding the structural behavior of the composite material after curing. Boundary conditions were found to affect the wrinkle amplitude and angle. Especially, constraining the laminate against expansion was found to increase the rate at which a wrinkle appears. The pre‐cure temperature was found to be the most important parameter to control, as the predictions show that slight variations in the pre‐cure temperature greatly influence the angle of the undulated fibers in the laminate. This shows the need for accurate temperature control and the need for uniform temperature across the mold to mitigate wrinkles in the curing process.