Frequency-dependent temperature evolution in NiTi shape memory alloy under cyclic loading

摘要: We present a simple analytical model to study the temperature evolution of superelastic NiTi shape memory alloy (SMA) bar under cyclic tensile loading. By dividing cycle into five characteristic stages and solving heat transfer equations for each stages, we obtain expressions loading different frequencies (cycle period tp) in convective ambients (characterized by time th). It is found that, due latent-heat release/absorption, specimen’s oscillates during loading, oscillation amplitude (δ stable ) increases with frequency reaches saturated value high-frequency range (tp/th < 0.1). Moreover, accumulated from intrinsic mechanical dissipation (internal friction), mean-temperature specimen frequency. The rise becomes significant range. These predictions quantitatively agree well experiments. (Some figures this article are colour only electronic version)