HTS-A钢对接接头低周疲劳寿命研究  

Study on low-cycle fatigue at butt joint of HTS-A steel

作　　者：严仁军[1] 周宏飞[1,2] 刘慧[1] 罗志明[1] 

机构地区：[1]武汉理工大学交通学院,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1期152-157,共6页Journal of Ship Mechanics

摘　　要：文章将HTS-A钢焊接试件的疲劳寿命分为裂纹萌生寿命和裂纹扩展寿命两部分。裂纹萌生寿命的估算采用局部应力应变法,并考虑平均应力和残余应力的影响。裂纹扩展寿命则基于断裂力学方法采用裂纹扩展速率公式进行估算。文章对HTS-A钢焊接试件进行了试验研究,在试验中,对裂纹何时出现和裂纹扩展情况的记录提出了新的方法。根据裂纹扩展情况回归了HTS-A钢焊趾处裂纹扩展速率参数(C、m),继而反推裂纹从0.5 mm直至试件断裂的扩展寿命。而总寿命减去裂纹扩展寿命则为裂纹萌生寿命。该分析方法统一了初始裂纹深度,对理论上研究焊接接头裂纹萌生寿命和裂纹扩展寿命提供了试验依据。试验结果表明,工程定义的裂纹萌生寿命不可忽略。另外,咬边缺陷对裂纹萌生寿命的影响很大,而对裂纹的扩展寿命影响十分小。通过试验结果的对比,也验证了HTS-A钢对接接头低周疲劳寿命估算方法的可靠性。Fatigue life of HTS-A steel welding test specimen is decomposed into the engineering crack-ini- tiation life and the crack-propagation life. The engineering crack-initiation life is estimated based on the local stress-strain method, with the influence of the mean stress and the residual stress considered. The crack- propagation life is estimated by the use of the crack propagation rate formula based on Linear E- lastic Fracture Mechanics （LEFM） method. Experimental study on HTS-A steel welding test specimens was conducted. New methods of scanning crack-initiation and recording crack propagation were proposed during test. Crack propagation rate parameters （C, m） of HTS-A steel at weld toe can be obtained as regression coefficients. According to above crack propagation rate parameters, the crack-propagation life is calculated from an assigned depth （0.5 mm） to specimen break. Subtraction of the total life from the crack-propaga- tion life is the engineering crack-initiation life. This method unifies initial crack depth, and provides an experimental basis for studying crack-initiation life and the crack-propagation life of the weld joint. The test results show that the engineering crack-initiation life can not be negligible. And welding undercut influences the engineering crack-initiation life significantly, but has no influence on the crack-propagation life. Through the verification of test results, the rehability of present estimating method on low-cycle fatigue life at butt joint of HTS-A steel is confirmed.

关 键 词：HTS—A钢 对接接头 萌生寿命 扩展寿命 低周疲劳 

分 类 号：U661.43[交通运输工程—船舶及航道工程]