基于弹塑性解析方程的薄片试样低周疲劳试验方法

Low Cycle Fatigue Test Method for Thin Sheet Specimens Based on Elastoplastic Analytical Equation

针对薄片漏斗试样,基于能量密度等效和量纲分析,提出了移幅-载荷幅关系(Relation between displacement-amplitude and load-amplitude,RDL)半解析方程;能量密度等效代表性体积单元(Representative volume element,RVE)的循环等效应力幅、等效应变幅(Cyclic equivalent stress-amplitudeandstrain-amplitude,CESS)解析方程;漏斗根部材料RVE单轴应变幅(Uniaxial strain-amplitude of material RVE at funnel root,US-R)半解析方程;材料与几何普适的薄片试样低周疲劳试验新方法。针对5种几何尺寸和13种预设材料组合的18种试样工况进行有限元分析,及对G115和16Mn进行薄片试样低周疲劳试验,结果表明,CESS解析方程预测的薄片漏斗试样等效应力幅-应变幅曲线与有限元预设曲线密切吻合,且新试验方法得到的G115和16Mn循环等效应力幅-应变幅关系和Manson-Coffin律与标准圆棒试样低周疲劳试验结果密切吻合。

Based on energy density equivalence and dimensional analysis,a new method is proposed for thin funnel specimen.A semi-analytical equation for Relation between displacement-amplitude and load-amplitude RDL was developed;Cyclic equivalent stress-amplitude and strain-amplitude CESS analytic equation of energy density equivalent representative volume element(RVE);Uniaxial strain-amplitude of material RVE at funnel root US-R semi-analytical equation;A new method for low cycle fatigue test of thin sheet specimens with universal material and geometry.The finite element analysis was carried out on 18 specimens with 5 geometrical sizes and 13 preset material combinations,and the low cycle fatigue test was carried out on G115 and 16Mn specimens.The results show that the equivalent stress-strain amplitude curves of the wafer funnel specimens predicted by the CESS analytic equation are in close agreement with the preset curves of the finite element equation.The cyclic equivalent stress-strain relations of G115 and 16Mn obtained by the new test method and Manson-Coffin law are in close agreement with the results of low cycle fatigue test of standard round bar specimens.