残余应力对铝合金在混和应力场中疲劳裂纹的延迟作用

基金项目:

国家重点基础研究规划项目(No.G19990650);国家自然科学基金项目(No.19972030)

Effects of residual stress on the delay of fatigue crack initiation in the mixed-mode stress field for aluminum alloys

摘要: 利用含内缺口的圆环试件,用实验和计算的方法,研究了两种铝合金在混和应力场下的孔边裂纹萌生特性,并利用扩孔形成的残余应力和变形,探讨对延迟裂纹继续发展产生的作用。扩孔残余应力场的存在使萌生裂纹的循环周次得到提高,对于Ⅰ型应力场,延迟裂纹萌生的效果非常明显,而对于Ⅰ型和Ⅱ型混合应力场,延迟裂纹萌生的效果较弱。
- 疲劳裂纹 /
- 残余应力 /
- 混合型应力场 /
- 扩孔
Abstract: Behavior of fatigue crack initiation from the hole edge of a circular ring specimen containing an internal notch was investigated experimentally and calculatedly for two aluminum alloys. Effects of an expanded hole that forms residual stress and deformation at the hole edge on the delay of fatigue crack initiation were studied. An obvious increase in the delay of crack initiation was obtained in the case of mode Ⅰ stress field due to the compressive residual stresses produced by the hole expansion process. However in the case of the mixed mode Ⅰ+Ⅱ the delay was less obvious because of the existence of shearing stress.
- fatigue crack /
- residual stress /
- mixed-mode stress field /
- expanded hole

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