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本文综合归纳了金属材料的冲击疲劳裂纹扩展研究。讨论了冲击应力特征参量 ,如应力幅值 ,加载时间 ,2次应力峰值和过载 ,对冲击疲劳裂纹扩展速率的影响 ;对材料在冲击和非冲击疲劳载荷作用下的裂纹扩展行为进行了比较。结果表明 :冲击应力特征参量对冲击疲劳裂纹扩展速率的影响规律与其裂纹尖端的微观变形、断裂机制有关 ;材料在冲击和非冲击疲劳载荷作用下的裂纹扩展速率存在 3种不同的关系 ,并取决于材料在冲击和非冲击疲劳载何作用下的裂纹扩展机理 ;应力幅值 ,应力花样和材料的显微组织对材料的冲击疲劳裂纹扩展的影响大于对非冲击疲劳裂纹扩展的影响 ,冲击载荷常导致材料脆化并加速材料的疲劳裂纹扩展。
This paper summarizes the impact fatigue crack growth of metal materials. The impact stress characteristic parameters, such as stress amplitude, loading time, secondary stress peak and overload, on the impact fatigue crack growth rate are discussed. The crack growth behavior of the material under impact and non-impact fatigue loads are compared. The results show that the impact of the characteristic parameters of impact stress on the fatigue crack growth rate is related to the microscopic deformation and fracture mechanism of the crack tip. There are three different relations between the crack growth rate and the crack propagation rate under the impact and non-impact fatigue loads The effect of stress amplitude, stress pattern and microstructure of material on the impact fatigue crack growth of the material is greater than that of non-impact fatigue crack propagation. The impact load Often lead to material embrittlement and accelerate the fatigue crack growth.