Simulation of damage process and experimental study of acoustic emission based on NREL 5 MW wind turbine blades

Abstract With the vigorous development of offshore wind power technology, long flexible blades have gradually become the focus of attention in the industry. However, the importance of blade safety inspection is also becoming increasingly prominent and cannot be ignored. This paper uses the NREL 5 MW wind turbine model as the research object to investigate potential damage areas and their evolution process during blade operation. Based on an accurate flow field simulation of the wind turbine model, a blade damage simulation study was conducted, which clearly presents the damage evolution process in dangerous areas. The accuracy of the simulation results was verified through bending damage experiments on characteristic units. The results of the study show that, based on the surface wind loads and the displacement of the vane sections presented in the flow field simulation results, it is believed that damage is more likely to occur between the 11th and 13th vane sections during the operation of the blade model. Through further damage simulation, it was found that three types of damage occurred in the hazardous area, namely matrix damage, delamination failure and fibre damage. The occurrence time and damage degree of the three types of damage were obtained, and the simulation results were finally verified with the help of acoustic emission experiments. It shows that the simulation analysis can assist the installation and arrangement of acoustic emission detection equipment on long flexible blades, predict the dangerous areas and the specific damage degree during the blade operation, and provide data support for the subsequent more accurate damage analysis.