Fatigue analysis of wind turbine blade materials using a continuum damage mechanics framework

Abstract

The work done for this thesis is related to fatigue analysis of various material types used in the wind turbine blades. For the analysis, a framework from the thermodynamics of irreversible processes with internal variables and Continuum Damage Mechanics (CDM) is used. Thermodynamic principles provide a generic framework that is valid for the entire fatigue phenomenon. CDM framework is then applied to characterize a specific mechanism under consideration. As the fatigue phenomenon consists of many mechanisms and their interactions, the scope of work is limited to setting the generic framework and to characterize only a few and their interactions to demonstrate the framework potential. The thesis consists of four main sections: introduction, theory, mathematical formulation, and validation. Before starting the framework construction, a decent idea about vastness in fatigue analysis methodologies adopted by the research community is required. Hence chapter 1 is prepared to give readers, not in detail, but a helicopter view of the field. This overview allows drafting the achievable scope and methodology for this research work keeping in mind the ultimate goal of analysing full-scale wind turbine blade sustaining fatigue throughout its operational life.