Progressive Damage Simulation of Laminates in Wind Turbine Blades under Quasistatic and Cyclic Loading

The overall purpose of this Ph.D. project has been to develop a framework of methods for progressive delamination modeling and simulation of composite laminates in large scale structures under both quasi-static and fatigue loading.
The first part of the thesis is an introduction to the project and provides a short introduction to selected basic topics of the theoretical background of the work presented in the papers.
The second part of the thesis consists of three refereed journal papers.
Paper A is concerned with computational efficiency and the ability to converge to a solution for large cohesive elements applied in delamination analyses.
Paper B presents a review of the available experimental observations, the phenomenological models and the computational simulation methods for the three phases of fatigue-driven delamination (initiation, onset and propagation).
Paper C presents a new method for simulating fatigue-driven delamination under general mixed mode conditions. The experimental crack growth rate can be reproduced in finite element analyses with practically no error for any given structure and load.