压弯组合应力下的表面裂纹应力强度因子表达式(英文)  

A Modified Stress Intensity Factor Expression Subjected to Combination of Compressive and Bending Stresses

作　　者：谌伟[1] 严仁军[1] 徐琳[1] 秦凯[1] 张新宇[2] 耿黎明[2] 

机构地区：[1]武汉理工大学高速船舶工程教育部重点实验室,武汉430063 [2]中国舰船研究设计中心,武汉430064

出　　处：《船舶力学》2014年第3期303-316,共14页Journal of Ship Mechanics

摘　　要：文章主要提出了一种基于单轴疲劳参数预估多轴疲劳扩展寿命的工程修正方法。为了分析压应力对于焊接件疲劳寿命的影响,文开中展了HTS-A钢对接焊接试件的单轴和双轴疲劳试验研究。试验结果表明,双轴疲劳试验中试件断口形式是以Ⅱ型裂纹为主导的Ⅰ型/Ⅱ型混合型裂纹,因此文中基于最大剪切面上的剪应力和法向应力提出了一种能够适用于压弯组合应力下的等效应力强度因子幅。新的ΔK不仅考虑了最大剪应力的效果,而且考虑了正应力的影响。最后,将基于修改的ΔK表达式预估的结果同试验结果作了对比分析,结果表明该应力强度因子可采用单轴疲劳参数,适用于弯曲载荷和压弯组合,为估算多轴应力状态下的应力强度因子及其疲劳裂纹扩展寿命提供了参考。The main aim of this paper is to provide a modified engineering methodology able to esti-mate the multiaxial crack propagation life based on uniaxial fatigue parameters. In order to analyze the influence of compressive load, uniaxial and biaxial fatigue tests were conducted on welding spec-imens of HTS-A steel. The experimental results show that fatigue fracture of biaxial specimens are mixed-mode and predominated by ModeⅡ, therefore a new equal ΔK subjected to combined com-pressive and bending loads is proposed based on the equivalent method of the shear stress and nor-mal stress. The equal ΔK not only takes into account the role of maximum shear stress, but also con-siders the effect of normal stress. Finally, comparisons are made between the result of this modifiedΔK expression and the corresponding experimental data. The result shows that modified stress inten-sity factor expression can adapt to the uniaxial fatigue parameters and be suitable for combined compressive and bending loads, which provides a reference for estimating stress intensity factor and fatigue crack propagation life under multiaxial loads.

关 键 词：双轴疲劳 应力强度因子 裂纹扩展速率 疲劳寿命 低周疲劳试验 

分 类 号：U661.43[交通运输工程—船舶及航道工程]