Smart Prestressing with Shape-Memory Alloy
Publication: Journal of Engineering Mechanics
Volume 124, Issue 10
Abstract
Shape-memory effect in nickel-titanium (nitinol) alloy was successfully utilized as a way of inducing additional prestressing in concrete. Strands made with NiTi (nickel/titanium) shape-memory alloy (SMA) wires were elongated beyond their plastic limit and subsequently were embedded in model concrete (mortar) beams. Upon electrical heating, a martensite-to-austenite phase transformation takes place and the material undergoes large shrinkage strains. This strain energy can be used to generate a significant prestressing force in concrete. Potentially, this provides a means of creating a “smart bridge,” where the amount of prestress can be increased or decreased as needed. Such a structure could actively accommodate additional loading, or remedy prestress losses over time. Properties of the SMA material and the micromechanics of its bond with concrete were investigated. Strands made with SMA wires were electrically actuated to induce deflection and failure in concrete (mortar) beams. Optical microscopy and the acoustic emission technique were used to understand the actuation mechanisms.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Buehler, W. J., Gilfrich, J. V., and Wiley, R. C. (1963). J. Appl. Phys., 34, 1475.
2.
Duerig, K. W., and Melton, K. N.(1989). “Designing with the shape-memory effect.”MRS Int. Meeting on Advanced Mat., 9, 581.
3.
Iyer, S. L., and Sripathy, G. (1996). “First posttensioned deck bridge with composite cables.”Proc., 4th Mat. Engrg. Conf., ASCE, Reston, Va., 375–385.
4.
Lange, D. A., Ouyang, C., and Shah, S. P. (1996). “Behavior of cement based matrices reinforced by randomly dispersed microfibers.”Advanced Cement Based Mat. J., 3(1).
5.
MacGregory, J. G. (1996). Reinforced concrete, 3rd Ed., Prentice-Hall, Inc., Englewood Cliffs, N.J.
6.
Maji, A. K., and Sahu, R.(1994). “Acoustic emissions from reinforced concrete.”Experimental Mech. J., 34(4), 379–388.
7.
Maji, A. K., Satpathi, D., and Kratochvil, T.(1997). “Acoustic emission source location using lamb wave modes.”J. Engrg. Mech., ASCE, 123(2), 154–161.
8.
Shape Memory Applications, Inc. (1997). Web page www.sma-inc.com/NiTiTechmenu.htm1 or sma-inc.com./SMAPaper.htm1.
9.
Wayman, C. M. (1993). “Shape memory alloys.”MRS Bull., 49.
10.
White, S. R., Whitlock, M. E., Ditman, J. B., and Hebda, D. A. (1993). “Manufacturing of adaptive graphite-epoxy structures with embedded nitinol wires.”Adaptive structures and materials systems—AD V 35, ASME, New York, 71.
Information & Authors
Information
Published In
Journal of Engineering Mechanics
Volume 124 • Issue 10 • October 1998
Pages: 1121 - 1128
Copyright
Copyright © 1998 American Society of Civil Engineers.
History
Published online: Oct 1, 1998
Published in print: Oct 1998
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.