考虑裂纹尖端应力场常数项T应力对裂纹断裂特性的影响，对平均应变能密度准则进行修正，建立混合型裂纹扩展条件计算式。在此基础上，系统分析常数项T应力对I型、II型、I-II混合型裂纹断裂判据的影响。结果表明，常数项T应力降低了材料裂纹起裂阻力，且参数|Bα|越大裂纹断裂极限值越低，|Bα|相同时，正T应力要比负T应力更容易发生断裂。基于修正平均应变能密度准则，预测双轴疲劳载荷作用下平板表面I型裂纹扩展寿命。结果表明，考虑常数项T应力影响后的疲劳裂纹扩展寿命约为传统疲劳裂纹扩展寿命的49%。
The averaged strain energy density criterion is modified by considering the constant term T-stress. The crack onset propagation formulation of mixed mode I-II-III crack were then given. The mode I, mode II and mixed mode I-II crack onset propagation behavior were investigated thoroughly. The analysis results show that the crack onset propagation limit will be reduced by considering T-stress. The greater the parameter |Bα| is, the easier the fracture will take place. Fracture will more easily happen when the T-stress is positive at a given parameter |Bα|. The crack growth life of the plate surface mode I crack under longitudinal tensile load and lateral compressive load simultaneously were analyzed based on the traditional reference variable ΔKΙ and the proposed reference variable ΔKeq. The analysis results show that T-stress has a significant effect on mode I surface crack growth life, the crack growth life will be overestimated by neglecting the T-stress effect.
2020,42(2): 20-24 收稿日期：2019-06-24
DOI：10.3404/j.issn.1672-7649.2020.02.003
分类号：O346.1
作者简介：黄如旭(1987-),男,高级工程师,研究方向为船舶与海洋工程结构疲劳与断裂理论、实验及数值模拟
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