Fatigue features study on the crankshaft material of 42CrMo steel using acoustic emission

Abstract

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 crankshaft blank, respectively. The analysis methods of parameter-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.

Keywords

acoustic emission / fatigue failure / remanufacturing crankshaft / wavelet analysis

References

[1] Zhou X, Yu X. Fatigue crack growth regular tests for engine crankshaft and analysis on the mechanism. Chinese Journal of Mechanical Engineering, 2008, 44(01): 238–242

[2] Zhou X, Yu X. Frequency sweep method for crankshafts’ fatigue crack growth rate measurement. Journal of Zhejiang University (Engineering Science), 2007, 41(11): 1886–1892 (in Chinese)

[3] Hao R, Lu W, Chu F. Review of diagnosis of rolling element bearings defaults by means of acoustic emission technique. Journal of Vibration and Shock, 2008, 27(3): 75–79 (in Chinese)

[4] Elforjani M, Mba D. Detecting natural crack initiation and growth in slow speed shafts with the acoustic emission technology. Engineering Failure Analysis, 2009, 16(7): 2121–2129

[5] Han Z, Luo H, Cao J, et al. Acoustic emission during fatigue crack propagation in a micro-alloyed steel and welds. Materials Science and Engineering, 2011, 528(25–26): 7751–7756

[6] Zhang Z, Li G, Wang H, Monitoring fatigue wear of the coating based on acoustic emission. Tribology, 2012, 32(1): 89–95

[7] Hase A, Mishina H, Wada M. Correlation between features of acoustic emission signals and mechanical wear mechanisms. Wear, 2012, 292–293(292): 144–150

[8] He Y, Yin X, Chu F. Modal analysis of rubbing acoustic emission for rotor-bearing system based on reassigned wavelet scalogram. Journal of Vibration and Acoustics, 2008, 130(6): 061009

Acknowledgements

This research was supported by the National Natural Science Foundation of China (Grant Nos. 51535011 and 51275151).

RIGHTS & PERMISSIONS

2016 Higher Education Press and Springer-Verlag Berlin Heidelberg