In-Situ Fatigue Sensors for Structural Health Monitoring of Highway Bridges
Fatigue damage in bridges has been identified as a threat to bridge safety. Fatigue cracks in steel structures are well-known to occur at stresses lower than typical design stresses. Short fatigue cracks can be difficult to detect by visual inspection and therefore can be easily overlooked. Since a larger portion of fatigue life in metals is spenton crack nucleation than on propagation, it is vital to develop methods of detecting such damage. We will discussthe initial development work of an in-situ fatigue sensor to detect fatigue damage in steel bridges. The concept of the fatigue sensor is built on the strain-life fatigue analysis method and Miner’s damage summation rule. The fatigue sensor is made of electrically conductive material with notched sensor arms with varying stress concentration factors; each arm is designed to fail at different numbers of stress cycles to indicate the accumulation of damage in the structural member to which it is attached. The concept has been verified for constant amplitude cyclic loading in the laboratory. A finite element analysis has been carried out for the sensor and the results are compared. Future work will address the case of variable amplitude loading.
KeywordsFatigue Life Fatigue Damage Structural Health Monitoring Notch Root Steel Beam
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- 1.Zhang, Y., In Situ Fatigue Crack Detection using Piezoelectric Paint Sensor, Journal of Intelligent Material Systems and Structures, 17(843), 2006.Google Scholar
- 2.ODOT, Pontis Bridge Inspection Manual for Oklahoma Bridges, Oklahoma Department of Transportation - Bridge Division, 2006.Google Scholar
- 3.Gongkang, F., ed. Non Destructive Testing For Steel Highway Bridges. NDT Methods Applied to Fatigue Reliability Assessmement of Structures, ed. J. Mohammadi, American Society of Civil Engineers, 2004.Google Scholar
- 4.Jackson, C.N., Sherlock, C. N., Nondestructive Testing Handbook: Leak Testing, Library of Congress Cataloging-in-Publication Data, 1998.Google Scholar
- 5.Son, J., Mohammadi, J., ed. A Review of Non-destructive Test Methods for Bridges. NDT Methods Applied to Fatigue Reliability Assessmement of Structures, ed. J. Mohammadi, American Society of Civil Engineers, 2004.Google Scholar
- 6.Rakow, A., Chang, F. K., An In-Situ Sensor Design for Monitoring Fatigue Damage in Bolted Joints, in 6th International Workshop on Structural Health Monitoring (IWSHM), DEStech Publications, Inc: Stanford, CA, 2007.Google Scholar
- 7.Gongkang, F., Non Destructive Testing For Steel Highway Bridges, in NDT Methods Applied to Fatigue Reliability Assessmement of Structures, J. Mohammadi, Editor, American Society of Civil Engineers, 2004.Google Scholar
- 8.Fisher, J.W., Kulak, G. L., Smith, I. F. C., Fatigue Primer for Structural Engineers, National Steel Bridge Alliance, USA, 1998.Google Scholar
- 10.VISHAY. Special Use Sensors - Crack Propagation Sensors, Document Number: 91000, Revision: 18- Jul-08. 2008; Available from: http://www.vishay.com/docs/11521/crackpro.pdf.
- 11.Bannantine, J.A., Comer, J. J., Handrock, J. L., Fundamentals of Metal Fatigue Analysis, Prentice-Hall, 1990.Google Scholar
- 12.F.D.+E. Experimental HTML Fatigue Database, Fatigue Design and Evaluation Committee of the SAE Experimental Web Site at the University of Waterloo, 2009.Google Scholar
- 13.Peterson, R.E., Stress Concentration Factors, John Wiley & Sons, Inc.,1974Google Scholar