摘要
利用QBS-100电液伺服疲劳试验机对带中心圆孔的P20钢低周疲劳特性进行了研究,并借助长焦显微镜和普通CCD镜头对试样表面裂纹的演化规律进行了在线观测。试验发现,P20钢的裂纹均萌生于与载荷加载方向垂直的孔边缘,萌生期较短;主裂纹的扩展以裂纹连接的方式向前跳跃传播,无次生裂纹产生。应力控制的低周疲劳条件下,疲劳寿命与应力幅存在良好的双对数关系。试验结果表明,视觉测量方法可很好实现对疲劳裂纹萌生、演化直至断裂全程在线观测。
The low cycle fatigue characteristics of P20 steel specimens with central hole were investigated on a QBS-100 Electro-hydraulic servo fatigue testing machine. By means of a long focal distance microscope and a CCD camera, the initiation and propagation of surface cracks were observed online status. It was found that cracks initiated from the edge of the hole in a short time and the propagation paths were perpendicular to the loading direction. It was also found that cracks could propagate by jumping extension through coalescence, no secondary cracks produced. In these tests, a nearly liner logarithmic relations between fatigue lifetime and stress amplitude was obtained. The results stated that the vision measurement method was helpful to observe the initiation and propagation of surface cracks online.
作者
孙涛
陈昌海
方琴
李艳丽
Sun Tao;Chen Changhai;Fang Qin;Li Yanli(Sichuan Engineering Technical College, Deyang, Sichuan, 618000, China)
出处
《装备制造与教育》
2018年第4期51-54,共4页
Equipment Manufacturing and Education
基金
德阳市科技支撑计划项目,项目编号:2014ZZ045
关键词
低周疲劳
裂纹
视觉测量
P20钢
low cyclic fatigue
cracks
vision measurement
P20 steel
