Damages of wind turbine blade trailing edge: Forms, location, and root causes

Abstract

The geometrical form and the manufacturing technique make the trailing edge of the wind turbine blade more susceptible to damage. In this study the trailing edge in a number of 81blades of 100kW wind turbines and 18blades of 300kW wind turbines of working life ranging between 6.5×107and 1.1×108cycles were completely visually scanned. The different damages were classified and allocated in their exact position relative to the blade length. Cracks in different orientations with the blade length were the frequent types of damages which found on the trailing edge. First, longitudinal cracks (LCs) that found along the blade trailing edge from the blade root to the tip were in lengths that varied from a few centimeters up to around 1.35m. Second, transverse cracks (TCs) were found in either simple TCs which growing on one shell at the trailing edge or round TCs which growing across the two shells. TCs lengths were ranging from 20 to 50mm. Third, edge damages were detected in the form of edge cuts or crushing. The possible root causes of the different types of cracks have been discussed.