Wind Energy is a rapidly growing market and the demand for wind turbine blades is increasing constantly. Unfortunately, very little quality inspection is carried out on these large scale fibreglass sandwich structures and the failure rate has been increasing leading to costly repairs and downtime. Laser Shearography has been successfully used to detect many defects including wrinkles, delaminations and dryspots in a production and in-field environment. The full-field, non-contact technique enables fast coverage of large areas which represents a significant cost save for operators and manufacturers by allowing defects to be repaired before they cause blade failure. Digital Image Correlation (DIC) has been used to quantify the effect of the defects on the structural integrity of the blade as well as for material coupon testing. The effect of the defect can be seen as a strain riser on the surface strain distribution as the blade is loaded. Measurements on coupon tests allow validation of FEA models. For the first time, the results presented show the close alignment between Laser Shearography and Digital Image Correlation results. The poster shows laser Shearography and DIC results obtained on full-size wind turbine blades in-field and in-production focusing on the detectable defects and the effect they have on the strain distribution.
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