拉伸过载对裂纹张开应力影响的量化分析
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摘要
为快速地估算拉伸过载作用下裂纹张开应力,本文提出基于裂纹最大张口位移变化量来计算裂纹张开应力方法。针对单次过载、多次连续过载,考虑了过载比、应力比、材料特性的影响,通过弹塑性有限元分析建立中心穿透裂纹张开应力与最大张口位移变化量的函数关系,该函数关系适用于不同形式的连续拉伸过载的硬化金属材料;对于间断过载,量化分析了过载距离对裂纹扩展的影响,发现当过载距离等于0.233倍,高载塑性区时迟滞效应最强,为获得最佳迟滞效果提供了有效的施加方案。
To obtain crack opening stress( σop) under tensile overloading quickly,an approach was proposed to determine σopbased on the variable quantity of maximum crack opening displacement( VMCOD). On the basis of elastic-plastic finite element analysis,the functional relationship between σopand VMCOD of a center-cracked specimen was established to determine the effects of stress ratio,overload ratio,and material properties. The relationship was applicable for determining σopof metallic hardening materials under multiple overloads. For the intermittent overload,the effect of distance between overloads on crack propagation was investigated. Results show that the maximum retardation occurred when the distance between overloads was 0. 233 times that of the high-load plastic zone.Thus,the proposed approach was an effective scheme for obtaining optimum retardation.
To obtain crack opening stress( σop) under tensile overloading quickly,an approach was proposed to determine σopbased on the variable quantity of maximum crack opening displacement( VMCOD). On the basis of elastic-plastic finite element analysis,the functional relationship between σopand VMCOD of a center-cracked specimen was established to determine the effects of stress ratio,overload ratio,and material properties. The relationship was applicable for determining σopof metallic hardening materials under multiple overloads. For the intermittent overload,the effect of distance between overloads on crack propagation was investigated. Results show that the maximum retardation occurred when the distance between overloads was 0. 233 times that of the high-load plastic zone.Thus,the proposed approach was an effective scheme for obtaining optimum retardation.
引文
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[13]LUGO M,DANIEWICZ S R,NEWMAN J C.A mechanics based study of crack closure measurement techniques under constant amplitude loading[J].International journal of fatigue,2011,33(2):186-193.
[14]李亚智,耿伟杰,束一秀,等.高载作用下的疲劳裂纹闭合与残余应力作用[J].西北工业大学学报,2014,32(4):529-535.LI Yazhi,GENG Weijie,SHU Yixiu,et al.Fatigue crack closure and residual stress effect of overload[J].Journal of Northwestern Polytechnical University,2014,32(4):529-535.
[15]陈景杰,李玉刚,黄一.硬化材料裂尖塑性区尺寸简便计算方法研究[J].华中科技大学学报(自然科学版),2013,41(12):101-105.CHEN Jingjie,LI Yugang,HUANG Yi.Simple method to calculate crack-tip plastic zone of hardened materials[J].J Huazhong Univ of Sci&Tech(natural science edition),2013,41(12):101-105.
[16]HEPER R.Elastic-plastic material response of fatigue crack surface profiles due to overload interactions[J].International journal of fatigue,2003,25(9/11):801-810.
[2]LESIUK G,CORREIA J A F O,De JESUS A M P,et al.Fatigue crack propagation behavior of old puddle iron including crack closure effects[J].Procedia structural integrity,2016,2:3218-3225.
[3]VORMWALD M,SEEGER T.The consequences of short crack closure on fatigue crack growth under variable amplitude loading[J].Fatigue&fracture of engineering materials&structures,1991,14(2-3):205-225.
[4]AGUILAR E A A,FELLOWS N A,DURODOLA J F.Experimental measurement of crack opening and closure loads for 6082-T6 aluminium subjected to periodic single and block overloads and underloads[J].International journal of fatigue,2013,47:71-82.
[5]ANTUNES F V,CAMAS D,CORREIA L,et al.Finite element meshes for optimal modelling of plasticity induced crack closure[J].Engineering fracture mechanics,2015,142:184-200.
[6]KWOFIE S,RAHBAR N.An equivalent driving force model for crack growth prediction under different stress ratios[J].International journal of fatigue,2011,33(9):1199-1204.
[7]HU D,YANG Q,LIU H,et al.Crack closure effect and crack growth behavior in GH2036 superalloy plates under combined high and low cycle fatigue[J].International journal of fatigue,2017,95:90-103.
[8]ANTUNES F V,CORREIA L,RAMALHO A L.A parameter for quantitative analysis of plasticity induced crack closure[J].International journal of fatigue,2015,71:87-97.
[9]OCHENSBERGER W,KOLEDNIK O.Overload effect revisited-investigation by use of configurational forces[J].International journal of fatigue,2016,83:161-173.
[10]CHEN F L,WANG F,CUI W C.An improved constitutive model to predict fatigue crack growth rate under constant-amplitude loading with single and multiple overload[J].Proceedings of the institution of mechanical engineers,Part M:journal of engineering for the maritime environment,2011,225(3):271-281.
[11]JIANG S,ZHANG W,LI X,et al.An analytical model for fatigue crack propagation prediction with overload effect[J].Mathematical problems in engineering,2014,2014:1-9.
[12]尤萌,陈景杰,黄一.平面状态下张开应力的准确评估[C]//第九届武汉地区船舶与海洋工程研究生学术论坛论文集.中国武汉,2016.YOU Meng,CHEN Jingjie,HUANG Yi.The Accurate Assessment of Crack Opening Stress in Plane Stress and Plane Strain[C]//The Proceedings of the 9th Wuhan Postgraduates Academic Forum on Ship and Ocean Engineering.Wuhan,China,2016.
[13]LUGO M,DANIEWICZ S R,NEWMAN J C.A mechanics based study of crack closure measurement techniques under constant amplitude loading[J].International journal of fatigue,2011,33(2):186-193.
[14]李亚智,耿伟杰,束一秀,等.高载作用下的疲劳裂纹闭合与残余应力作用[J].西北工业大学学报,2014,32(4):529-535.LI Yazhi,GENG Weijie,SHU Yixiu,et al.Fatigue crack closure and residual stress effect of overload[J].Journal of Northwestern Polytechnical University,2014,32(4):529-535.
[15]陈景杰,李玉刚,黄一.硬化材料裂尖塑性区尺寸简便计算方法研究[J].华中科技大学学报(自然科学版),2013,41(12):101-105.CHEN Jingjie,LI Yugang,HUANG Yi.Simple method to calculate crack-tip plastic zone of hardened materials[J].J Huazhong Univ of Sci&Tech(natural science edition),2013,41(12):101-105.
[16]HEPER R.Elastic-plastic material response of fatigue crack surface profiles due to overload interactions[J].International journal of fatigue,2003,25(9/11):801-810.