Development of Progressive Failure Models and Their Application to Open Hole Composite Laminates and Wind Turbine Blades

Date

2023-3-02

Author

Muyan, Mevlüt Can

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The usage of composite materials in the load carrying aircraft structures has been increasing in the last few decades. Composite materials are also used in wind turbine blades, which are designed to endure extreme weather conditions without being damaged over a lifespan of 20 years. Within the framework of this dissertation, the root cause and propagation of damage in two types of composite structures subjected to uniaxial and combined loading are studied. In the dissertation three different studies are presented. The first study is on the development of a proposed analytic Extended Point Stress Method (EPSM) for the strength prediction of quasi-isotropic carbon-epoxy open hole laminates. EPSM is advantageous over traditional analytical models as it is applicable not only under uniaxial but also combined loading. The second study is on a finite element model incorporating continuum damage model and cohesive zone model for the strength prediction of quasi-isotropic carbon-epoxy open hole tension (OHT) laminates. In the study, the necessity of modeling interface failure in OHT laminates that fail in brittle failure mode with minimal delamination is highlighted. The third study deals with the FE model validation and progressive damage analysis of a 5-meter composite wind turbine blade under monotonic loading. After validating the FE model based on modal tests, blade progressive damage analysis under flap-wise (max) loading is conducted. The failure initiation region is predicted in the blade root transition region and the blade collapses after maximum loading level.

Subject Keywords

Open hole composite laminate, Finite element model, Progressive damage analysis, Wind turbine blade, Continuum damage model

URI

https://hdl.handle.net/11511/103027

Collections

Graduate School of Natural and Applied Sciences, Thesis