Abstract Fatigue strength analysis of critical components plays a vital role for ensuring structural integrity and operational reliability of major equipment. In notched components, the concept of cyclic plastic zone (CPZ) is commonly utilized for fatigue cracking analysis, in which the CPZ size normally relates to the material strength. In particular, materials with higher yield stress have shown smaller CPZ size and vice versa. According to this, a new approach for determining closed-form stress at the notch tip is proposed by considering the size of cyclic plastic zone, which can be used for the notch tip stress evaluation along the load direction under cyclic loadings. By implementing FE analysis, experimental data of 304 stainless steel, 40Cr steel and Ti-6Al-4V alloy are utilized for model validation and comparison. Results show that the scope of damaged CPZ alters the notch tip stress under fatigue loadings, and the proposed model yields better correlation of fatigue life predictions with experimental results of the three materials than other two models.

中文翻译：

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基于循环塑性区的缺口分析和金属疲劳寿命预测损伤演化模型

摘要 关键部件的疲劳强度分析对于保障重大装备的结构完整性和运行可靠性具有重要作用。在缺口部件中，循环塑性区 (CPZ) 的概念通常用于疲劳裂纹分析，其中 CPZ 大小通常与材料强度有关。特别是，屈服应力较高的材料显示出较小的 CPZ 尺寸，反之亦然。据此，提出了一种考虑循环塑性区大小的确定缺口尖端封闭形式应力的新方法，可用于循环载荷下沿载荷方向的缺口尖端应力评估。通过有限元分析，利用304不锈钢、40Cr钢和Ti-6Al-4V合金的实验数据进行模型验证和比较。