The reliability analysis of fatigue propagation life with non-normal \=random parameters taking T-stress into account
Received:March 09, 2009  Revised:October 10, 2009
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KeyWord:fatigue life  crack constraint  non-normal random parameters  fourth moment method  reliability
张艳林 东北大学 机械工程与自动化学院,沈阳
张义民 东北大学 机械工程与自动化学院,沈阳
金雅娟 东北大学 机械工程与自动化学院,沈阳
张艳芳 防灾科技学院 数学系,三河
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      The study of fatigue crack propagation life based on fracture mechanics often ignore the higher order term of the crack tip stress expansion. This will cause the crack growth simulation error. This paper simulates the fatigue crack propagation considering the T-stress which influences the crack propagation angle. From the results, T-stress delays the propagation life of the plate. Based on the modified Paris-Endogan formula fatigue crack propagation life of a plate with a slope crack along the left edge and subjected to constant distributed stress at up&down edges of the plate is analyzed. The direction of the crack propagation follows the two-parameter modified maximum tensile stress criterion. Because of the geometrical dimension, material property, mechanical loads are often random variables, crack growth behavior is random process. Based on the former research, considering material properties and loads as non-normal random parameters, the variable reliability of fatigue crack propagation life to the targeted life is calculated using Stochastic Finite Element Method, Fourth Moment Method and Edgeworth series. This method can predict the behavior of the crack growth of plates and the reliability of it.