Factors Controlling Superelastic Damping Capacity of SMAs
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In this paper, questions linked to the practical use of superelastic damping exploiting stress-induced martensitic transformation for vibration damping are addressed. Four parameters, particularly vibration amplitude, prestrain, temperature of surroundings, and frequency, are identified as having the most pronounced influence on the superelastic damping. Their influence on superelastic damping of a commercially available superelastic NiTi wire was experimentally investigated using a self-developed dedicated vibrational equipment. Experimental results show how the vibration amplitude, frequency, prestrain, and temperature affect the capacity of a superelastic NiTi wire to dissipate energy of vibrations through the superelastic damping. A special attention is paid to the frequency dependence (i.e., rate dependence) of the superelastic damping. It is shown that this is nearly negligible in case the wire is in the thermal chamber controlling actively the environmental temperature. In case of wire exposed to free environmental temperature in actual damping applications, however, the superelastic damping capacity significantly decreases with increasing frequency. This was explained to be a combined effect of the heat effects affecting the mean wire temperature and material properties with the help of simulations using the heat equation coupled phenomenological SMA model.
Keywordsshape memory alloys superelastic damping thermomechanical testing
- 1.Liu Y., Zeliang Xie Z., Humbeeck J., Cyclic deformation of NiTi shape memory alloys, Materials Science and Engineering, A273–275 (1999) 673–678.Google Scholar
- 11.L. Heller, P. Sittner, and J. Pilch, Impact of Heat Effects on Superelasticity, Proceedings of ICOMAT 2008, 29/6 to 5/7/2008, Santa Fe, New Mexico, submittedGoogle Scholar
- 13.J. Van Humbeeck and L. Delaey, The Influence of Strain-Rate, Amplitude and Temperature on the Hysteresis of a Pseudoelastic Cu-Zn-Al Single Crystal, J. Phys., 1981, Col C5, Tome 42, p C5-1007-1011Google Scholar