【摘要】 考虑到裂尖不同程度的塑性变形，选择合适的断裂参量并准确预测疲劳裂纹扩展速率是一项非常重要的任务。采用4种不同疲劳加载条件，通过理论计算与实验分析探究了裂纹尖端断裂参量与疲劳裂纹扩展速率之间的关联，最后通过公式与参数拟合对疲劳裂纹扩展速率预测提供合适的模型。结果表明，随着载荷比和载荷幅的提高，ΔK表征疲劳裂纹扩展逐渐失去了其合理性和有效性。裂纹扩展前期，高载荷比裂纹扩展阻力更大。在裂纹扩展后期，高、低载荷比裂纹扩展阻力差距在缩小。在所有讨论的断裂参量中，ΔJa′c是适合工业纯钛疲劳裂纹扩展的断裂参量，在此基础上提出了相应的疲劳裂纹扩展速率预测模型。更多还原

【Abstract】 It’s an important task that choosing appropriate fracture parameters and predicting the fatigue crack growth rate accurately considering the different degrees of plastic deformation at the crack tip. The relation between crack tip fracture parameters and a fatigue crack growth rate was investigated by theoretical calculation and experimental analysis under four different fatigue loading conditions. Finally,a suitable model for predicting a fatigue crack growth rate was provided by formulas and the parameter fitting. The results indicate that ΔK representing a fatigue crack growth rate loses its rationality and effectiveness gradually with increases of the load ratio and the load amplitude. At the early stage of the crack propagation,the crack propagation resistance of high load ratio is higher than low load ratio. At the later stage of the crack propagation,the gap between high and low load ratios and the crack growth resistance decreases. ΔJ′_ac is the suitable fracture parameter for the fatigue crack propagation of the industrial pure titanium among all of the fracture parameters discussed. On this basis,the corresponding prediction model of the fatigue crack growth rate was proposed.更多还原