Abstract:

The crack tip temperature field of blade with micro-defect based on the thermo-mechanical was studied. The microstructure damage mode of specimen fracture was proposed. The numerical model of the crack tip temperature field was established by the plastic zone and the internal heat flux density function. The plastic zone boundary model of Ⅰ/Ⅱ crack propagation with micro-defects wind turbine blade was deduced by crack tip stress of orthotropic composite and Tsai-Wu failure criterion. The heat flux density function of crack tip temperature field was constructed by crack propagation law. The fracture failure microstructure of the blade specimen was examined by scanning electron microscopy(SEM). The surface temperature of wind blade specimen with micro-defect by infrared thermography was monitored. The surface temperature of specimen was consistent with numerica l result of crack tip temperature field. The power of heat flux density function is 2. It was found that the damage modes of blade specimen with bubble defects were fiber fracture, matrix cracking.

Key words: wind turbine blades, infrared thermography, heat dissipation, crack tip temperature field, microstructure, damage, bubble defect, heat flux density function