中文摘要：

通过轴向循环拉压实验获得漏斗试样载荷-位移（P-V）曲线,并基于该曲线和有限元反演分析方法获得了材料的循环本构关系.利用该循环本构关系对漏斗试样进行三维扭转有限元分析,获得漏斗根部剪切应力与扭矩之间的转换公式,及漏斗根部剪切应变与名义扭角之间的转换公式,实现了漏斗试样扭转低周疲劳的研究.应用该方法,完成了C250钢漏斗试样常温下一条曲线的扭转低周疲劳实验,揭示了C250钢的疲劳行为,并给出了该材料的Manson-Coffin寿命预测模型.

英文摘要：

Load-displacement (P-V)curve has been obtained of funnel specimen based on cyclic uniaxial tension and compression ex-periment,Based on the test results and finite element analysis iterative method,the effective cyclic constitutive relationships of C250 steel have been obtained.By using these effective cyclic constitutive relationships,3D finite element analyses of funnel specimen under torsion are used to reveal the transforming relationship between the torque and the shear stress at the root of funnel specimen,the rela-tionship between the nominal torsional angle and the shear strain at the root of funnel specimen.On the basis of those analyzing meth-od,the low cycle fatigue study under torsion has been achieved.A series of torsional fatigue tests on C250 steel at room temperature by using funnel specimens have been carried out,the low cycle fatigue behavior of C250 steel has been revealed,and the typical Manson-Coffin model is employed to predict the torsional fatigue life of C250 steel.