高温多轴载荷下低周疲劳寿命预测  

Fatigue Life Predictions under Multiaxial Loading at High Temperature

作　　者：金丹[1,2] 王昭春 田大将[2] 钟瑜 

机构地区：[1]天津大学化工学院,天津300072 [2]沈阳化工大学能源与动力工程学院,辽宁沈阳110142 [3]盘锦辽河油田锦州采油厂作业一大队,辽宁锦州121209

出　　处：《沈阳化工大学学报》2013年第4期343-346,363,共5页Journal of Shenyang University of Chemical Technology

基　　金：国家自然科学基金项目(11102119);国家重点基础研究发展计划项目(2011CB706504);辽宁省教育厅项目(L2011066)

摘　　要：针对Mod.9Cr-1Mo铁素体钢进行550℃下多轴低周疲劳试验,定义主应变比用以考虑不同的比例程度对多轴疲劳寿命的影响.针对各路径和各幅值下的循环软化特性进行分析,对比结果表明:路径对循环软化特性的影响大于应变幅值对循环软化特性的影响,其软化程度随扭转载荷所占比例增加而增加.采用最大正应变方法、最大剪应变方法和von Mises等效应变法进行疲劳寿命预测,结果表明:最大正应变方法针对扭转路径得到的预测结果偏于安全;最大剪应变方法预测扭转路径较好,但对于单轴路径给出的预测结果过于不安全;等效应变法得到的预测结果偏于保守.A series of tests for low cycle fatigue were conducted for Mod. 9Cr-lMo ferrite steel under multiaxial loading at 550 ~（2. The effect of strain multiaxiality under proportional loading on the fatigue life was considered by defining the principal strain ratio. The cyclic properties under different strain paths and strain amplitudes for this material were discussed. It was shown that the softening property was ob- served at high temperature for all the strain paths. The effect of loading path on the softening property was more prominent than that of strain amplitude. The fatigue life was predicted by the maximum normal strain approach, the maximum shear strain approach, and von Mises equivalent strain approach. It was shown that the prediction results of the maximum normal strain approach were more conservative for torsional load- ing. On the contrary, the prediction results of the maximum shear strain approach were satisfactory for tor- sional loading and nonconservative for uniaxial loading. The prediction results were conservative and close to the results from the maximum normal strain approach.

关 键 词：MOD 9CR-1MO钢 主应变比 循环软化特性 疲劳寿命预测 

分 类 号：TG155.5[金属学及工艺—热处理]