Fatigue Crack Length Real Time Measurement Method Based on Camera Automatically Tracking and Positioning

Abstract:

Fatigue crack propagation test is a very important testing way to study the metallic engineering material fatigue fracture characteristics by on-line measuring crack length under the cyclically varying loads. Crack length has been obtained through crack image capture, image processing and image analysis. In order to improve the crack measurement precision when the fatigue crack keeps growing, a new crack length real time measurement method based on the image processing and camera automatically tracking techniques was presented in this paper. This method includes the crack image processing algorithms and camera tracking and positioning movement control. The crack length measurement errors based on the camera tracking and fixed camera are respectively 0.076mm and 0.148mm.The experiment results show the proposed method has greatly improved the crack length measuring precision with the ordinary optical device.

• Periodical: Applied Mechanics and Materials (Volumes 130-134)
• Pages: 3111-3118
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.130-134.3111
• Online since: October 2011
• Authors: Hong Li Gao, Shan Shan Shen, Yan Yun
• Keywords: On-Line Measurement, Camera Automatically Tracking, Fatigue Crack, Image Processing

References

[1] Ravikumar Varadarajan, Clare M. Rimnac. Compliance calibration for fatigue crack propagation testing of ultra high molecular weight polyethylene. Biomaterials 27 (2006), p.4693–4697.

DOI: 10.1016/j.biomaterials.2006.05.003

[2] Vitaly Pavelko, Eric Ozolinsh. Detection of a fatigue crack by method of an acoustic emission. Transport and Telecommunication Vol. 3, N1, 2002，p.75—84.

[3] C. B. Arnold, B. Pratap, A. Piqué, A. B. Geltmacher. Laser-Micromachined and Defect Arrays for DC Potential Drop Fatigues Sudies. SPIE LASER 2004, January 2004, pp.26-30.

[4] ISO12108: 2002, Metallic materials-Fatigue testing- Fatigue crack growth method.

[5] F.V. Diaza, A.F. Armasa, G.H. Kaufmanna, G. E Galizzia. Nondestructive evaluation of the fatigue damage accumulation process around a notch using a digital image measurement system. Optics and Lasers in Engineering, Volume 41, Issue 3, March 2004, p.477.

DOI: 10.1016/s0143-8166(03)00018-6

[6] Ryu D.H., Choi T.W., Kim Y.I., Nahm S.H. Measurement of the fatigue-crack using image processing techniques. Fourth International Conference on Knowledge-Based Intelligent Engineering Systems and Allied Technologies/ Proceedings. KES'2000，Brighton, UK, 30 August-1 September 2000, pp.121-124.

DOI: 10.1109/kes.2000.885773

[7] Vanlanduit S, Vanherzeele J, Longo R, Guillaume P， A digital image correlation method for fatigue test experiments. Optics and Lasers in Engineering, Volume 47, Issues 3-4, March-April 2009, pp.371-378.

DOI: 10.1016/j.optlaseng.2008.03.016

[8] C. Kanchanomai, S. Yamamoto, Y. Miyashita, Y. Mutoh, A. J. McEvily. Low cycle fatigue test for solders using non-contact digital image measurement system. International Journal of Fatigue, Volume 24, Issue 1, January 2002, pp.57-67.

DOI: 10.1016/s0142-1123(01)00052-4