Structural integrity assessment of repurposed wind turbine blade composite components with acoustic emission testing and Ib-value analysis

Abstract

Wind power is an essential renewable energy source; however, the increasing volume of end-of-life (EoL) wind turbine blade (WTB) composite components poses a challenge to its sustainability. Economically viable recycling solutions for these WTBs in industrial applications are limited. However, repurposing subcomponents of EoL WTBs for second-life applications is an alternative concept for maintaining the excellent mechanical properties of composite material. While non-structural repurposing (e.g., furniture applications) has been explored, structural repurposing has not been widely implemented due to unresolved safety concerns. To address this problem, this study proposes an innovative quantitative structural integrity assessment method for EoL WTB components using acoustic emission testing and statistical Ib-value analysis. Unidirectional virgin and end-of-life glass fiber composite specimens were evaluated under tensile and cyclic loading. It was found that there were fewer early-stage fiber breakages, but more accelerated damage propagation following pre-existing damage in the EoL specimens. The obtained Ib-value from the stepwise cyclic loading test exhibited a strong correlation with the values from the tensile test, thereby highlighting that the combination can be used as a reliable structural integrity criterion. This research provides insights into advanced reliability assessment technology for EoL WTB components, enabling their structural repurposing in second-life applications, such as beams. This approach extends the service life of composite material and helps to reduce the EoL WTB material stream.