Evaluation for Vibrational Characteristics of CFRP Wind Turbine Blade

Abstract

In the recent years, CFRP was recognized as the main material for fabricating large scale wind turbine blades. However, there is some likelihood of damage occuring in the thickness direction of CFRP laminates caused by impact loads because there are no fibers. If the bending and compressive loads are applied to the damaged area, the buckling and the compression failure easily arise. So, it is desirable to evaluate interior damage with a non-destructive method. In this paper, the vibration characteristics of the CFRP wind turbine blades were evaluated by using an impulse hammer test. The natural frequencies and the damping ratios of the CFRP wind turbine blades were measured and their vibration mode shapes were obtained from modal analysis software. Furthermore, the experimental results were compared with numerical ones obtained by FEM.