Modeling the stress-induced transition behaviour of shape memory alloy using mixture theory

Takeshi Okuyama 2Yun Luo 1Masaru Higa 1Toshiyuki Takagi 2Minoru Matsumoto 2

1. Tohoku Unversity Biomedical Engineering Research Organization (TUBERO), Sendai, Japan
2. Institute of Fluid Science, Tohoku University (IFS), Sendai, Japan


In this paper, the modeling of the mechanical constitutive relation during stress-induced transitions of shape memory alloys (SMAs) is discussed based on mixture theory. When the initial state of SMA material was a mixture of austenite parents and twinned martensite variants, external stresses for this material would induce both the reorientation from twinned martensite variants to detwinned martensite variants and the transformation from austenite parents to detwinned ones. Corresponding internal variables to describe these transitions are newly defined. This model enables the numerical prediction of the overall mechanical behavior of SMA materials in the temperature range from Ms to Mf. The approach of mixture theory; a series model is applied in the formulation of the constitutive behavior of SMAs with isostress conditions. Tensile tests have been carried out with Ti-Ni specimens in a temperature range including martensite transformation temperatures. Numerical simulation based on the proposed model accurately predicted the mechanical behavior of stress-induced transitions in the concerned temperature range.


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Presentation: oral at E-MRS Fall Meeting 2005, Symposium C, by Takeshi Okuyama
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-05-31 07:15
Revised:   2009-06-07 00:44