Investigation of Soil-Structure Interaction Effects on Damage Detection of Wind Turbine Tower with Biorthogonal Wavelets

Wind has been one of the cleanest sources of energy. The tendency to use wind turbines has been a growing trend in the world in recent decades. The size and capacity of wind turbines are increasing rapidly in order to obtain more wind energy. Statistics show that more giant turbines are more broken down and require more maintenance. The goal of wind farm owners is to monitor work to reduce downtime and increase the efficiency of each wind turbine. The wind turbine tower carries the entire wind turbine and is the second-largest cost of the wind turbine. Damage to the tower can endanger the entire wind turbine and cause extensive damage. However, the background to the study of the health monitoring of the wind turbine tower against its mechanical installations is insignificant. Besides, no comprehensive research has been conducted on the health monitoring of the tower with soil-structure interaction included. In this study, biorthogonal wavelets were used to process the mode shape of the damaged tower. The foundation is a square concrete foundation 20 m × 20 m and 1 m in depth. Two different soils, a normally consolidated clay and dense sand, are considered. Eighteen failure scenarios were defined. The results of this study indicate that the use of side-to-side mode shapes of the tower has a tangible advantage over its fore-aft mode shapes for detecting the failure. Considering the desirable effect of soil-structure interaction on damage detection, it is necessary to examine this effect in the analysis.