【摘要】 为探究4130X钢Ⅰ-Ⅱ复合型疲劳裂纹扩展规律，采用紧凑拉伸剪切（CTS）试样，开展不同加载角度、应力比下的试验及有限元分析（FEM）。结果表明：裂纹扩展路径不受应力比R的影响，随加载角度β的增大产生较大的偏转角度，起裂扩展角符合最大周向应力（MTS）准则；疲劳裂纹扩展速率(FCGR)随应力比R的增大而增快，随着加载角度β的增加而降低；裂纹尖端的塑性区形态会随加载角度而发生变化，塑性应变能在扩展过程中逐渐累积；断口形貌特征表明，应力比R和加载角度β会对断口处的疲劳辉纹以及二次裂纹产生明显的影响。更多还原

【Abstract】 To investigate the behavior of mixed mode Ⅰ-Ⅱ fatigue crack growth in 4130X steel, Compact Tension Shear(CTS) specimens were used to conduct experimental methods and Finite Element Method(FEM) at diverse load ratios and loading angles. The results indicate that the fatigue crack growth path is not influenced by the load ratio(R), but a significant deflection angle occurs with an increase in the loading angle(β). The crack growth angles are consistent with the Maximum Tangential Stress(MTS) criterion. The fatigue crack growth rate(FCGR) shows an increasing trend as load ratio(R) increases, but decreases with an increase of the loading angle(β). With the increment of the loading angle, the morphology of the monotonic plastic zone at the crack tip varies, and the plastic strain energy is accumulated gradually. Fracture morphology analysis reveals that the load ratio(R) and loading angle(β) have a significant impact on the fatigue striations and secondary cracks at the fracture surface.更多还原