Effect of Impact Damages on the Strength of Wind Turbine Blade

This paper studies the application of carbon fiber in the blades of wind turbines to decrease structural weight and increase their residual strength after impact. The authors modified the impact testing method to test the elements of the blades and standard specimens and studied the types of impact damage of carbon fiber reinforced polymer using NDI. It is found that the nature of damage propagation in the specimens depends on the type of weave in reinforcement material and the study made it possible to conclude the best match between the type of weaving and the maximum impact load in the entire range of impact energies. It was learned how mechanical properties of carbon fiber-reinforced polymer decrease after impact depending on various weaving patterns. A finite-element-based method was developed and validated for analyzing the stress-strain behavior of the plates with an equivalent hole under compression. The stress-strain behavior model of the plates demonstrated good agreement with the experimental data in the entire range of concentrator sizes. Finally, compressive strain properties of the damaged samples were studied using a non-contact video system, which made it possible to understand the behavior of damaged polymer composite structure after impact.