风力机叶片复合材料裂尖温度场及微观损伤研究

依据热力耦合建立含微缺陷叶片的裂尖温度场数值模型，并研究了微缺陷叶片断裂微观损伤方式。首先，建立裂尖温度场数学模型需要确定塑性区范围和塑性区内的内热流密度函数。基于正交各向异性复合材料裂纹尖端应力场和Tsai-Wu屈服准则理论推导，得到含微缺陷风电叶片Ⅰ/Ⅱ复合型裂纹的塑性区范围；内热流密度函数按照裂纹扩散规律构造。其次，利用电子扫描电镜技术对叶片试件的断口失效微观结构进行检测。通过红外热像仪监测微缺陷叶片试件表面温度实验，验证了裂尖温度场计算模型的准确性；确定计算温度场模型中内热流密度函数幂数为2；通过显微技术发现含气泡缺陷的叶片试件有纤维断裂、基体开裂损伤方式。

Study on Crack Tip Temperature Field and Microstructure Damage for Wind Turbine Composite Blade

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.