ULTRASONIC RAYLEIGH WAVE INSPECTION OF WAVINESS IN WIND TURBINE BLADES: EXPERIMENTAL AND FINITE ELEMENT METHOD

This paper presents the investigation of discrete, out-of-plane waviness in thick composite plates with applications to wind turbine blades. The investigation was carried out with the help of air coupled ultrasonics and a two-step procedure was framed to assist production line implementation. The first step involved detection of marcels, and the second step involved the characterization of these marcels with the help of an index called aspect ratio. A set of standardized samples with known aspect ratios were fabricated and used for this study. Finite element models were created to understand the wave propagation in wavy composite plates. All the experimental data was correlated with numerical B-Scans and conclusions concerning the method were made.