多轴应变疲劳损伤模型实验研究

用应变控制进行了双轴应变循环试验，研究了Ａ３钢与４０Ｃｒ钢两种材料的循环应力－应变关系，由当量累积损伤因子与当量循环滞回能之间的规律与联系，建立了当量损伤因子与当量累积滞回能的归一化关系；采用圆管试件在室温条件下，进行了拉压循环和轴向加扭转复合多级循环试验。结果表明，用八面体塑性剪应变幅描述的当量损伤因子与当量滞回能可用来进行多轴累积损伤分析。

EXPERIMENTAL STUDY ON DAMAGE OF MULTIAXIAL STRAIN FATIGUE

A damage modelling for multiaxial low cyclic fatigue is investigated on test. Biaxial damage behavior of both mild steel and 40Cr steel are studied. Tubular specimens of two grades of steels were subjected to simultaneous circulation of push and pull,as well as altenating twist at room temperature under the conditions of four ratios of shear strain to axial strain.A relation of equivalent damage number and an equivalent hysteresis energy was established on the basis of known fatigue lives under uniaxial and biaxial loading. Damage summation can be made at each level of equivalent plastics shear strain range.