Quantitative research into millimetre-scale debonding defects in wind turbine blade bonding structures using ultrasonic inspection: numerical simulations

摘要

Wind turbine blades are one of the most important components of a wind turbine. In the manufacturing process, debonding defects are often produced between the adhesive and the main spar, which will affect the performance of the component. Ultrasonic testing (UT) for debonding defects in composite materials has been proven to be effective. Quantitative studies of defects play an important role in gaining an in-depth understanding of the overall mechanical properties of components. This paper examines the quantitative relationship between ultrasonic parameters and millimetre-scale debonding defects through simulation. The relationship between the debonding size and the maximum amplitude of the echo is analysed in detail using time-domain analysis and short-time Fourier transform (STFT) time- frequency analysis. Fitting formulae for the peak ratio for four values of debonding rate are obtained and the STFT time- frequency diagrams can help to visually distinguish between different levels of defect. The simulation results can be used as a reference for future experiments.