摘要
针对拉伸超载作用下疲劳裂纹尖端应力分布进行线弹性有限元仿真分析,采用航空用高强铝合金2024-T4为试验材料,对裂纹尖端附近局部奇异状态和拉伸超载后引起的裂纹尖端附近巨大的塑性变形和裂纹分叉状态进行仿真模拟,结果表明:通过对比裂纹尖端应力分布云图,超载扩大了裂纹尖端塑性区的范围,增加了残余应力对裂纹扩展的影响,含分叉裂纹对裂纹尖端最大应力有所削弱,对降低裂纹尖端应力强度因子有所贡献,会导致疲劳裂纹扩展速率降低,增加疲劳裂纹扩展寿命。
In the process of fatigue crack growth,the stress distribution at the crack tip is complex and changeable,which is more difficult to predict under overload.In this paper,the stress distribution at the tip of fatigue crack under tensile overload is simulated by linear elastic finite element method.2024-T4,a high strength aluminum alloy used in aviation,is used as the test material to simulate the singular state of the layout near the crack tip and the large plastic deformation and crack bifurcation near the material crack tip caused by tensile overload.The results show that by comparing the stress distribution at the crack tip in the stress distribution nephogram,overload enlarges the scope of the plastic zone at the crack tip,increases the influence of residual stress on the crack propagation.The bifurcated crack weakens the maximum stress at the crack tip and contributes to the reduction of the stress intensity factor at the crack tip,which will reduce the rate of fatigue crack propagation and increase the fatigue crack propagation life.
作者
雷贝贝
刘荣伟
LEI Bei-bei;LIU Rong-wei(Institute of SERVO Technology Design, Guizhou Aerospace Control Technology Co., Ltd,Guiyang 550000, Guizhou, China;Industrial Technology Center, Chengde Petroleum College, Chengde 067000, Hebei, China)
出处
《承德石油高等专科学校学报》
CAS
2020年第4期46-49,58,共5页
Journal of Chengde Petroleum College
关键词
超载
裂纹尖端应力分布
裂纹分叉
应力强度因子
有限元
overload
stress distribution at crack tip
crack bifurcation
stress intensity factor
finite element
