Damage detection in a composite wind turbine blade using 3D scanning laser vibrometry

Abstract

As worldwide wind energy generation capacity grows, there is an increasing demand to ensure structural integrity of the turbine blades to maintain efficient and safe energy generation. Currently, traditional non-destructive testing methods and visual inspections are employed which require the turbine to be out-of-operation during the inspection periods, resulting in costly and lengthy downtime. This study experimentally investigates the potential for using Lamb waves to monitor the structural integrity of a composite wind turbine blade that has been subject to an impact representative of damage which occurs in service. 3D scanning laser vibrometry was used to measure Lamb waves excited at three different frequencies both prior to, and after, impact to identify settings for an optimal system. Signal processing techniques were applied to the datasets to successfully locate the damage and highlight regions on the structure where the Lamb wave was significantly influenced by the presence of the impact damage. Damage size resulting from the impact was found to correlate well with the laser vibrometry results. The study concluded that acousto-ultrasonic-based structural health monitoring systems have great potential for monitoring the structural integrity of wind turbine blades.

Development of an automated assessment technology for detecting damage in body armour

“…The AU principle of damage detection has been applied to a variety of structures and materials in a range of work using lab-based equipment 12,[16][17][18][19][20][21][22][23][24][25][26] . Researchers such as Fu et al 27 The concept of the developed device is presented in Figure 2.…”

“…A technique that quickly and clearly identifies the presence of damage whilst performing AU is cross-correlation. 16–19 The technique compares the similarity of the two waveforms returning a value between one (where two waves are identical – indicating no damage) and zero. A value below one indicates that there is a change in the wave, which if below a certain threshold indicates that damage is present.…”

Topology optimization of vibrational piezoelectric energy harvesters for structural health monitoring applications

“…Vibration harvesting is a promising area where substantial research has been focused. This is due to the abundance of vibrational energy available in aircrafts and other structures which require SHM, including bridges (Godı´nez-Azcuaga and Obdulia, 2013), gear boxes (Prieto et al, 2016), and wind turbines (Marks et al, 2017). Typically, vibrational energy harvesting can be split into three general categories: piezoelectric, electromagnetic, and electrostatic; a comprehensive review of each of these has been conducted by Wei and Jing (2017).…”

Impact monitoring of CFRP composites with acoustic emission and laser Doppler vibrometry

“…It does this by analysing the change in frequency and phase within the backscattered laser reflected from a surface; this change is the result of structural vibration causing Doppler shift within the laser [19]. Researchers have used LDV for a range of NDT applications, including modal analysis [20,21] and acoustoultrasonic inspection [22][23][24], however to the best knowledge of the authors, not for assessing high frequency AE from impact damage in composites.…”