Correlation of Pseudoelastic NiTi Egineering and True Stress-Strain Curves on the Effects of Nickel Titanium Composition

 
 
 
  • Abstract
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  • Abstract


    This research highlights the novel properties of pseudo-elastic Ni-Ti bar owing to their ability to reverse macroscopically  inelastic deformation during earthquake known as recentering capability and large elastic strain capacity which  originated from the reversible austenite to martensite phase transformation.  Hence, this paper presents and evaluates  the cyclic  properties of pseudo elastic Ni–Ti shape memory alloys to assess their prospective use for seismic applications to be exploited as seismic resistant design and retrofit. In addition,  the correlation of hysteretic behavior of Ni-Ti alloy in terms of cyclic loading number and history, mechanical properties at ambient temperature, equivalent damping, energy dissipation and  recovery stress were evaluated. The NiTi bar  used is with weight percentage of  Ti-43.98 at. % Ni 56.02 and diameter of 12 mm. The tensile cyclic test obtained demonstrated a rounded loading curve based on a 0.2 % offset. The as received bar exhibited superior pseudo-elastic behaviour and recentering through repeated cycling without significant degradation or permanent deformation but low energy dissipation due to narrow hysteresis while the steel rebar showed vice versa. Experimental results show potential for the use of SMAs in seismic applications and provide areas for continued research. It was concluded that the as-received pseudo elastic Ni-Ti bar is suitable for use in seismic mitigation despite of their ability to undergo cyclical strains at 6 % which is greater than 5 %, with minimal residual strain of 0.15% which is less than 1%.  

     

     



  • Keywords


    Shape memory alloy; Nickel Titanium ratio; Pseudoelastic; Phase Transformation; Engineering and True Stress-strain Relationship

  • References


      [1] I. Faridmehr, M. Hanim Osman, A. Bin Adnan, A. Farokhi Nejad, R. Hodjati, and M. Amin Azimi, “Correlation between Engineering Stress-Strain and True Stress-Strain Curve,” Am. J. Civ. Eng. Archit., vol. 2, no. 1, pp. 53–59, 2014.

      [2] J. Mccormick et al., “Structural Engineering with NiTi . II : Mechanical Behavior and Scaling,” no. September, pp. 1019–1029, 2007.

      [3] M. Dolce and D. Cardone, “Mechanical behaviour of shape memory alloys for seismic applications 1 . Martensite and austenite NiTi bars subjected to torsion,” vol. 43, pp. 2631–2656, 2001.

      [4] J. Kłaput, “Studies of selected mechanical properties of nitinol – shape memory alloy,” vol. 10, no. 3, pp. 155–158, 2010.

      [5] R. Desroches, M. Asce, J. Mccormick, and M. Delemont, “Cyclic Properties of Superelastic Shape Memory Alloy Wires and Bars,” vol. 130, no. 1, pp. 38–46, 2004.

      [6] I. Faridmehr, M. Hanim Osman, A. Bin Adnan, A. Farokhi Nejad, R. Hodjati, and M. Amin Azimi, “Correlation between Engineering Stress-Strain and True Stress-Strain Curve,” Am. J. Civ. Eng. Archit., vol. 2, no. 1, pp. 53–59, Mar. 2014.

      [7] R. DesRoches, J. McCormick, and M. Delemont, “Cyclic Properties of Superelastic Shape Memory Alloy Wires and Bars,” J. Struct. Eng., vol. 130, no. 1, pp. 38–46, Jan. 2004.

      [8] A. Abdulridha, D. Palermo, S. Foo, and F. J. Vecchio, “Behavior and modeling of superelastic shape memory alloy reinforced concrete beams,” Eng. Struct., vol. 49, pp. 893–904, 2013.

      [9] Y. Zhao, M. Taya, Y. Kang, and A. Kawasaki, “Compression behavior of porous NiTi shape memory alloy,” Acta Mater., vol. 53, no. 2, pp. 337–343, 2005.

      [10] M. S. Alam, M. Moni, and S. Tesfamariam, “Seismic overstrength and ductility of concrete buildings reinforced with superelastic shape memory alloy rebar,” Eng. Struct., pp. 8–20, 2012.


 

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Article ID: 27774
 
DOI: 10.14419/ijet.v7i4.14.27774




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