Lamination and Delamination in Wind Turbine blades
Lamination
Historically, wind turbine blades (made of thermoset resin and fiberglass as well as other composite materials) were manufactured using the hand-lay-up process.
The disadvantage of manual lamination is the difficulty of properly controlling the amount of resin in the laminate. Excess resin compromises the mechanical performance of the part, leaving it fragile and heavy.
But today, vacuum infusion is the process that manages to very well control the amount of resin in the laminate and very well impregnate the reinforcing fibers (glass and carbon).
The wind turbine blades are manufactured by vacuum infusion, as are the hulls of vessels, as shown in the photo.
Delamination
Delamination is what happens to a [composite material when its layers start to separate.
Delamination occurs between the layers of the reinforcement (generally glass fabric) and the matrix (generally epoxy resin), leaving the region with a whitish appearance.
The main mechanical failures in polymeric composites occur at the fiber-matrix interface and are characterized by this interlaminar detachment.
For maximum strength of the composite, it is necessary that the matrix elongates at least by the same amount as the reinforcing fibers. Therefore, good adhesion between matrix and reinforcement is necessary for the load transfer to be efficient and to avoid delamination during a mechanical. load on the wind blade.
Juliana Lucena, Dr. in Energy (UFPE), Production Engineer (USP), Professor at the Federal Network