Abstract
In the present work, simple tensile test of shape memory alloys (SMAs) is studied by considering stress concentration caused by the grippers. In order to simulate SMA behaviors, finite element method is employed to obtain prestress distribution along the specimen due to fastening the grippers prior to the application of tension. Then, Brinson’s 1-D constitutive model is used to study transformations during the tensile loading–unloading. It is found that the prestress leads to a non-uniform distribution of uniaxial stress as well as martensite volume fraction throughout a wire. Therefore, the so-called dog-bone geometry is suggested and optimum dimensions are proposed to obtain a uniform tensile stress distribution when testing an SMA specimen. This way, a nearly simultaneous transformation can be achieved along the whole specimen. The optimum dimensions are shown to be different from those reported by ASTM for tensile testing of SMAs. In fact, the optimum dimensions depend on material parameters of the test specimen.
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Jamalimehr, A., Ravanbakhsh, H., Kadkhodaei, M. et al. Investigation of Dog-Bone Geometry for Simple Tensile Test of Pseudoelastic Shape Memory Alloys. Iran J Sci Technol Trans Mech Eng 40, 337–345 (2016). https://doi.org/10.1007/s40997-016-0037-1
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DOI: https://doi.org/10.1007/s40997-016-0037-1