Wind turbine composite blade manufacturing : the need for understanding defect origins, prevalence, implications and reliability.

Abstract

Renewable energy is an important element in the US strategy for mitigating our dependence on non-domestic oil. Wind energy has emerged as a viable and commercially successful renewable energy source. This is the impetus for the 20% wind energy by 2030 initiative in the US. Furthermore, wind energy is important on to enable a global economy. This is the impetus for such rapid, recent growth. Wind turbine blades are a major structural element of a wind turbine blade. Wind turbine blades have near aerospace quality demands at commodity prices; often two orders of magnitude less cost than a comparable aerospace structure. Blade failures are currently as the second most critical concern for wind turbine reliability. Early blade failures typically occur at manufacturing defects. There is a need to understand how to quantify, disposition, and mitigate manufacturing defects to protect the current wind turbine fleet, and for the future. This report is an overview of the needs, approaches, and strategies for addressing the effect of defects in wind turbine blades. The overall goal is to provide the wind turbine industry with a hierarchical procedure for addressing blade manufacturing defects relative to wind turbine reliability.

Investigation of the Effect of In-Plane Fiber Waviness in Composite Materials through Multiple Scales of Testing and Finite Element Modeling

“…A 2008 study by Sandia National Laboratory found that 7% of wind turbine blades had to be replaced before reaching their expected lifetime. Due to each turbine having three blades, the chance of downtime caused by a blade failure is tripled (Cairns, Riddle, & Nelson, 2011). According to Sandia, blades have been responsible for 11% of turbine downtime recently.…”

“…The MSUCG is a third party investigator tasked with investigating the Effects of Defects. This has been broken into two subtasks (Cairns, Riddle, & Nelson, 2011):…”

Prospective challenges in the experimentation of the rain erosion on the leading edge of wind turbine blades

“…The damage should be understood as changes to the constitutive material and/or the geometric properties, including alterations to the boundary conditions and structural connectivity, which can adversely affect structural and power performance . Thus, several issues have been studied, eg, manufacturing process, fracture, fatigue, and adhesive joints . Although diverse turbine designs exist, currently the most common design is built in an upwind horizontal axis with three blades.…”

High-fidelity finite element models of composite wind turbine blades with shell and solid elements

“…However, relatively large numbers of repairs and early replacements are required ("Blade failure and load monitoring," 2008; Campbell, 2015). While many issues are related to the used manufacturing processes (Cairns et al, 2011;Nielow, 2014), this also indicates a need for detailed structural analysis to improve the understanding of the structure's behavior. This is possible by means of detailed finite element (FE) analysis.…”