【摘要】 用MTS 809拉-扭电液伺服材料试验机研究50CrVA弹簧钢标准试样以及各偏心试样在比例加载下的多轴疲劳寿命,并用扫描电子显微镜(SEM)对疲劳断口形貌进行观察。结果表明:比例加载下当弯曲应力幅值不超过等效应力的11%时,附加弯矩对试样的疲劳寿命无影响。各试样断口在疲劳扩展前期可以观察到轮胎花样;疲劳裂纹的扩展方向有周向和径向两种。断口上的疲劳特征为综合应力作用的结果;沿径向和周向分布的疲劳条带分别为轴向应力作用和扭转切应力作用的结果。更多还原

【Abstract】 The multiaxial fatigue life of 50 CrVA spring steel standard specimens and eccentric specimens under proportional loading was studied with MTS 809tension-torsion electro-hydraulic servo tester,and the morphology of fatigue fracture were analyzed by scanning electron microscopy(SEM).The results show that,when the bending stress amplitude is not more than 11% of the equivalent stress,additional bending moment can hardly have an effect on fatigue life of the specimens.At the fracture areas of all the specimens forming in the early stage of fatigue crack propagation,tire patterns can be found;fatigue cracks grow in two directions:circumferential and radial.Fatigue characteristics at the fracture are caused by combined stresses,fatigue striations distributing in the radial direction form because of the effect of axial stress,and fatigue striations distributing in the circumferential direction form owing to the effect of torsional shear stress.更多还原