Carbon fibre-reinforced polymer (CFRP) spar caps have enabled the manufacturing of increasingly large wind turbine blades, which are mostly made of glass fibre-reinforced polymer (GFRP). Nevertheless, the difference in stiffness between CFRP and GFRP can lead to delamination growth between both materials, jeopardising the structural integrity of the wind turbine blade.

This PhD project focuses on modelling, characterising, and experimentally studying fatigue delamination growth in the transition of the CFRP spar cap into the surrounding GFRP.

• First, a state-of-the-art fatigue propagation cohesive zone model is implemented in ANSYS, combined with a newly developed fatigue initiation model tailored to it.
• Second, the fracture properties of the interface between the CFRP and GFRP are characterised, using a newly developed fatigue characterisation procedure that prescribes the evolution of the energy release rate and eases the characterisation.
• Third, sub-component specimens representing the tapered CFRP spar cap transition are tested experimentally and numerically under fatigue loading.