Removing Residual Stress and Increasing Fatigue Life by Ultrasonic Method

Subject Areas : Mechanical Engineering

Ali Moarefzadeh ¹

1 - Department of Mechanical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran

Received: 2020-08-20 Accepted : 2020-12-01 Published : 2021-09-01

Keywords: Longitudinal Ultrasonic Wave, Stress intensity factor, Residual stress, Fatigue Life,

Abstract :

In this paper, a new method is introduced for evaluating effects of residual stress on fatigue life. The ability of ultrasonic method using longitudinal wave with critical angle of refraction or LCR wave in measuring and removing residual stresses due to welding was used. Two plates of alloy 2024-T351 were welded to each other. To measure their residual stress field acoustoelastic property was used and the changes in the speed of ultrasonic propagation of elastic waves when passing through the residual stress fields was investigated. In order to exert the effects of residual stress on fatigue life, the relations between the coefficients of effective stress intensity (SIF) and Fatigue Crack Propagation (FCP) rate in a state that the parts were welded together with residual stress under cyclic loading were obtained. Finally, ultrasonic waves with a certain frequency were used to remove the residual stresses. Also, the relationships between stress intensity factor and fatigue crack propagation rate were modified to predict fatigue life after removal of residual stresses. This method resulted in a 31% increase in fatigue life. The main reason for the increase in life was the plastic area created by the ultrasound wave. Therefore, it can be said that introduced method are suitable for using to remove residual stress due to welding.

References:

• Yaghi, Y., Becker, A., Weld Simulation Using Finite Element Methods, University of Nottingham, UK, 2004, pp. 7–11.


• Zubairuddin, M., Albert, S. K., Vasudevan, M., Mahadevan, S., Chaudhari, V., Suri, and V. K., Numerical Simulation of Multi-Pass GTA Welding of Grade 91 Steel, Journal of Manufacturing Process, Vol. 27, 2017, pp. 87–97.


• Hughes, D. S., Kelly, J., Second-Order Elastic Deformation of Solids, Physical Review, Vol. 92, 1953, pp. 1145-1953.


• Wozney, G. P., Crawmer, G. R., An Investigation of Vibrational Stress Relief in Steel, Welding Journal, Vol. 479, 1968, pp. 411-418.


• Lokshin, I., Vibration Treatment and Dimensional Stabilization of Castings. Russian Castings Production Journal, Vol. 7, 1965, pp. 454-456.


• Dawson, R., Moffat, D. G, Vibratory Stress Relief: A Fundamental Study of Its Effectiveness, Journal of Engineering Materials and Technology, Vol. 102, 1980, pp. 169-178.


• Walker, C. A, Waddell, A. H, and Johnston, D. G., Vibratory Stress Relief, an Investigation of the Underlying Processes, Journal of Process Mechanical Engineering, Vol. 209, 1995, pp. 51-58.


• Luh, G. C., Hwang, R. M., Evaluating the Effectiveness of Vibratory Stress Relief by a Modified Hole-Drilling Method. International Journal of Advanced Manufacturing Technology, Vol. 14, 1998, pp. 815-823.


• Munsi, S. M., Waddell, A. J., and Walker, C. A., The Influence of Vibratory Treatment on the Fatigue Life of Welds: A Comparison with Thermal Stress Relief, International Journal of Strain, Vol. 37, 2001, pp. 141-149.


• Sun, M. C., Sun, Y. H., and Wang, R. K, Vibratory Stress Relieving of Welded Sheet Steels of Low Alloy High Strength Steel, Material letters, Vol. 58, 2004, pp. 1396-1399.


• Hira, S., Aoki, S. H., Reduction of Residual Stress by Ultrasonic Surface Vibration. Advances in Vibration Engineering, Vol. 7, 2005, pp. 207-216.


• Liqun, D., Qijia, W., Experimental Study on Ultrasonic Stress Relief for Cured SU-8 Photo resist Layer, Microelectronic Engineering, Vol. 87, 2010, pp. 2555-2560.