中文摘要：

机轴被认为是引擎的一个重要部件，并且它是因为它的高增加的价值，重新生产的重要应用。然而，重新生产的机轴的疲劳失败研究仍然在它的主要阶段。因此，监视并且调查重新生产的机轴的疲劳失败是关键的。在这篇论文，声学的排放(AE ) 技术和机器视觉被用来监视 42CrMo 的四点的弯曲疲劳，它是机轴的材料。也就是，标本被划分成二个范畴先存在快克和非先存在的快克，它模仿机轴和机轴分别地挡住。基于参数的 AE 技术，小浪变换(WT ) 和 SEM 分析的分析方法被联合识别疲劳失败的阶段。疲劳失败的阶段是在重新生产的地里使用 AE 技术的基础机轴。实验结果证明疲劳裂缝繁殖风格是 transgranular 破裂，破裂是易碎的破裂。差别主要取决于裂缝开始的表格。各种各样的 AE 信号被参数分析方法检测。小浪阀值降噪和 WT 被联合到摘录光谱在不同疲劳失败阶段的 AE 信号的特征。

英文摘要：

Crankshaft is regarded as an important component of engines, and it is an important application of remanufacturing because of its high added value. However, the fatigue failure research of remanufactured crankshaft is still in its primary stage. Thus, monitoring and investigating the fatigue failure of the remanufacturing crankshaft is crucial. In this paper, acoustic emission （AE） technology and machine vision are used to monitor the four-point bending fatigue of 42CrMo, which is the material of crankshaft. The specimens are divided into two categories, namely, pre-existing crack and non-pre- existing crack, which simulate the crankshaft and crank- shaft blank, respectively. The analysis methods of para- meter-based AE techniques, wavelet transform （WT） and SEM analysis are combined to identify the stage of fatigue failure. The stage of fatigue failure is the basis of using AE technology in the field of remanufacturing crankshafts. The experiment results show that the fatigue crack propagation style is a transgranular fracture and the fracture is a brittle fracture. The difference mainly depends on the form of crack initiation. Various AE signals are detected by parameter analysis method. Wavelet threshold denoising and WT are combined to extract the spectral features of AE signals at different fatigue failure stages.