【作者】 叶笃毅； 曹汉杰； Olaf Hertel； Michael Vormwald；

【Author】 Ye Duyi~①Cao Hanjie~①Olaf Hertel~②Michael Vormwald~②(①Institute of Process Equipment and Control Engineering,Zhejiang University,Hangzhou,China) (②Fachgebiet Werkstoffmechanik,Technische Universitt Darmstadt,Germany)

【机构】 浙江大学化工机械研究所； Fachgebiet Werkstoffmechanik,Technical University in Darmstadt,Germany；

【摘要】 依据能量原理本文从理论上揭示出,当缺口件中应力集中部位的材料进入塑性时,Neuber准则将不可避免地高估缺口处的真实应力和应变,而等效应变能密度(ESED)方法趋于低估缺口根部的应力和应变值。通过对多轴应力状态下缺口尖端材料单元进行热力学分析,发展了一种统一的多轴缺口应力-应变简化计算表达式。该表达式使得Neuber准则和ESED方法成为两种特殊情况。采用比例和非比例拉-扭循环加载试验验证了本文建立的缺口应力-应变简化计算方法,并将计算结果与Neuber准则和ESED方法进行了比较。更多还原

【Abstract】 A simplified thermodynamics analysis of cyclic plastic deformation is performed in order to establish an energy transition relation for describing the elatic-plastic stress and strain behavior of the notch-tip material element in bodies subjected to multiaxial cyclic loads.Based on the thermodynamics analysis,it is deduced that in the case of elastic-plastic deformation,Neuber’s rule inevitably overestimates the actual stress and strain at the notch-tip,while the equivalent strain energy density(ESED)method tends to underestimate the actual notch-tip stress and strain.According to the actual energy conversion occurring in the notch-tip material element during cyclic plastic deformation,an unified expression for estimating the elastic-plastic notch stress-strain responses in bodies subjected to multiaxial cyclic loads is developed,of which Neuber’s rule and the ESED method become two particular cases,i.e.upper and lower bound limits of the notch stress and strain estimations.This expression is verified experimentally under both proportional and non-proportional multiaxial cyclic loads and a good agreement between the calculated and the measured notch strains has been achieved.更多还原