基于改进的统一疲劳裂纹扩展速率模型的表面裂纹扩展规律预报_英文_精选.pdf

第 卷第 期 船舶力学 15 6 Vol.15 No.6 年 月 2011 6 Journal of Ship Mechanics Jun. 2011 ： （ ） Article ID 1007-7294 2011 06-0660-09 Evaluation of Surface Crack Shape Evolution Using the Improved Fatigue Crack Growth Rate Model 1 1 2 WANG Fang , CUI Wei-cheng , HUANG Xiao-ping (1 China Ship Scientific Research Center, Wuxi 214082, China; 2 State Key Lab of Ocean Engineering, Shanghai Jiao Tong University, Shanghai 200030, China) Abstract: Many investigators have carried out the study on crack shape evolution law but some de- ficiencies are observed from the predicted results obtained using the existed methods. In this paper, an improved fatigue crack growth model was proposed. The nonlinear effect of the material, the clo- sure behavior of the crack front and its distribution along the crack front are sufficiently considered in this model, which will be used to evaluate the surface crack shape evolution. Moreover, by intro- ducing the concept of equivalent thickness at each point and the assumption of crack propagation at normal direction,the effect of different stress state at each point on crack shape evolution law is rea- sonably considered and the surface retardation due to boundary effect is successfully predicted. The evaluation precision of crack shape evolution law from this model is highly improved compared with the test data and the predicted curve from Paris law. Key words: the improved fatigue crack growth rate model; surface crack; crack shape evolution CLC n