低碳钢的大应变低周疲劳  

LOW CYCLE FATIGUE OF LOW CARBON STEELS UNDER LARGE STRAIN CYCLIC LOADING

作　　者：张以增[1] 李国琛[1] 徐明英[1] 杜明亮[1] 樊卫东[1] 

机构地区：[1]华中理工大学材料系,中国科学院力学研究所

出　　处：《机械强度》1995年第4期49-53,共5页Journal of Mechanical Strength

基　　金：国家自然科学基金;中国科学院基金

摘　　要：对三种低碳钢的不同缺口的轴对称圆柱形试样在大应变循环下的低周疲劳行为进行了研究。以考察失效周次在１００次以内的疲劳断裂行为。结果表明随着被控循环应变幅度的增大，低碳钢的低周疲劳寿命降低，断裂模式则由疲劳解理逐渐向延性韧窝过渡。缺口处的三向应力程度以及起始循环加载的静态损伤都对最终的疲劳失效有重要的影响。建议采用一种广义的循环应变参量上来概括影响这种大应变低周疲劳的诸因素，从而可以采用修正的Ｃｏｆｆｉｎ－Ｍａｎｓｏｎ关系式描述其疲劳行为。Axisymmetric notched bars with notch roots of large and small radii were tested under large straincyclic loading. The main attention is focused on the fracture behavior of steels having cycles to failure within therange 1～100. Our study shows that a gradual transition from a static ductile nature to one of fatigue cleavage canbe observed and characterized by the Coffin-Manson formula in a generalized form. Both the triaxial tensile stresswithin the central region of specimens and static damage caused by the first increasing load have effects on the finalfailure event.A generalized cyclic strain range parameter Δε is proposed as a measure of the numerous factors af-fecting behavior,Fractographs are presented to illustrate the behavior reported in the paper.

关 键 词：低周疲劳 大应变循环 累积损伤 低碳钢 

分 类 号：TG142.31[一般工业技术—材料科学与工程]