摘要
对P92钢在600℃下进行应力和应变控制的蠕变-疲劳试验,分析了载荷水平、保载时间对蠕变-疲劳损伤的影响;结合应力控制下的蠕变-疲劳试验数据,在黏塑性统一本构理论框架下引入修正的Chaboche非线性随动硬化率及蠕变应变并考虑损伤演化规律,构建了基于Chaboche理论的耦合蠕变-疲劳损伤本构模型,模拟了P92钢的蠕变-疲劳循环曲线。结果表明:P92钢在600℃下表现为循环软化特性;在应力控制下,P92钢高位保载的损伤与平均应力呈正相关,而低位保载的损伤与平均应力呈负相关;在应变控制下,P92钢产生应力松弛行为,保载时间越长,应力松驰越明显;建立的蠕变-疲劳损伤本构模型可以较好地模拟P92钢的循环特性,对于蠕变-疲劳过程中应力模拟的最大相对误差为7.30%。
Creep-fatigue tests under stress control and strain control were conducted on P92 steel at 600℃.The effects of load level and load holding time on the creep-fatigue damage were analyzed.By combination of stress controlled creep-fatigue test data,introducing the modified Chaboche nonlinear follow-up hardening rate and creep strain under the framework of viscoplastic unified constitutive theory,and considering the damage evolution law,the coupled creep-fatigue damage constitutive model based on Chaboche theory was established.The creep-fatigue cyclic curves of P92 steel were simulated.The results show that P92 steel exhibited cyclic softening characteristics at 600℃.Under stress control,the damage of P92 steel at high load holding was positively correlated with the average stress,while the damage at low load holding was negatively correlated with the average stress.Under strain control,P92 steel showed stress relaxation behavior,and the longer the load holding time,the more obvious the stress relaxation.The established creep-fatigue damage constitutive model could simulate the cyclic characteristics of P92 steel well,and the maximum relative error of the stress simulation in creep-fatigue process was 7.30%.
作者
曹宇
崔鑫
纪冬梅
CAO Yu;CUI Xin;JI Dongmei(College of Energy and Mechanical Engineering,Shanghai University of Electric Power,Shanghai 200090,China;NARI Technology Company Limited,Nanjing 211106,China)
出处
《机械工程材料》
CAS
CSCD
北大核心
2021年第10期50-57,65,共9页
Materials For Mechanical Engineering
