کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
278325 | 1430297 | 2011 | 8 صفحه PDF | دانلود رایگان |
This paper presents a simple thermo-mechanical model to explain and quantify the observed strain-rate dependence of the stress hysteresis of shape memory alloys (SMAs) bars/strips during stress-induced forward/reverse phase transition with latent heat release/absorption. By solving the convective heat transfer equation and employing the temperature dependence of the SMA’s transformation stresses, we are able to prove that the stress hysteresis depends non-monotonically on the applied strain rate with a peak appearing at an intermediate strain rate. We further showed that such a non-monotonic rate dependence is governed by the competition of phase-transition time (or latent-heat release/absorption time) and the time of heat exchange with the environment, and that the hysteresis peak is achieved when the two time scales become comparable. A bell-shaped scaling law of the rate dependence is derived, agreeing quantitatively well with the results of experiments.
► We model the rate dependence of the stress hysteresis of Shape Memory Alloys in a phase transition cycle.
► The hysteresis depends non-monotonically on the strain rate.
► Such non-monotonic rate dependence is governed by the ratio of loading time over the time of heat exchange.
► The hysteresis follows a bell-shaped scaling law with a peak when the ratio is close to unit.
Journal: International Journal of Solids and Structures - Volume 48, Issues 11–12, 1 June 2011, Pages 1688–1695