TWSME of a NiTi strip in free bending conditions:experimental and theoretical approach
Journal Title: Frattura ed Integrità Strutturale - Year 2014, Vol 8, Issue 29
Abstract
This paper deals with the two-way shape memory effect (TWSME) induced on a strip of a nearequiatomicNiTi alloy by means of the shape memory cycling training method. This procedure is based on thedeformation in martensite state to reach the desired cold shape followed by cycling the temperature from aboveAf to below Mf. To this end, the sample was thermally treated to memorise a bent shape, thermomechanicaltrained as described and thermally cycled in unloaded conditions in order to study the stability of the inducedTWSME. Heating to Af was reached by a hot air stream flow whereas cooling to Mf was achieved throughnatural convection. The evolution of the curvature with the increasing number of cycles was evaluated. Thethermomechanical behaviour of the strip undergoing uniform bending was simulated using a one-dimensionalphenomenological model based on stress and the temperature as external control variables. Both martensite andaustenite volume fractions were chosen as internal parameters and kinetic laws were used in order to describetheir evolution during phase transformations. The experimental findings are compared with the modelsimulation and a numerical prediction based on the approach proposed in [25].
Authors and Affiliations
A. Fortini, M. Merlin, R. Rizzoni, S. Marfia
Keywords
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- EP ID EP126620
- DOI 10.3221/IGF-ESIS.29.08
- Views 60
- Downloads 0
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