Application of one-dimensional phase transformation model to tensile-torsional pseudoelastic behavior of shape memory alloy tubes

Author(s):  
Tadashige Ikeda
2011 ◽  
Vol 148-149 ◽  
pp. 875-878
Author(s):  
Bo Zhou ◽  
Jun Lv ◽  
Gang Ling Hou ◽  
Ya Ru Pan

In this paper, the phase transformation behaviors of shape memory alloy (SMA) in the complex stress state are formulated based the one-dimensional phase transformation model supposed by Zhou and Yoon. The stress field near the crack tip of mode II in SMA is described based on linear elastic fracture mechanics. The phase transformation behaviors of SMA near the crack tip of Mode II are numerically investigated.


2012 ◽  
Vol 457-458 ◽  
pp. 994-997
Author(s):  
Bo Zhou ◽  
Xu Kun Li ◽  
Gang Ling Hou

This paper focuses on the thermo-mechanical behaviors of a shape memory alloy (SMA) plate with a circular hole under biaxial uneven tension. The phase transformation behaviors of SMA under complex stress state are formulated based on the one-dimensional phase transformation model developed by Zhou and Yoon. The stress field equation of the SMA plate with a circular hole is derived according to linear elastic mechanics. The phase transformation behaviors near the region around the circular hole are numerically simulated under different conditions of applied stress.


2009 ◽  
Vol 417-418 ◽  
pp. 229-232 ◽  
Author(s):  
Bo Zhou ◽  
Yan Ju Liu ◽  
Guang Ping Zou ◽  
Jin Song Leng

Shape memory alloy is a good candidate for realizing the passive control of structural vibration due to its excellent characteristic of energy dissipation. In this paper, the damping characteristic of shape memory alloy is quantitatively described based on Liang’s phase transformation model and thermo-mechanical constitutive equation for shape memory alloy. The vibration performances of a beam structure with shape memory alloy damper are investigated based on basic knowledge of vibration theorem. Numerical calculations show that the vibration of beam structure is well reduced by using the shape memory alloy damper.


2012 ◽  
Vol 457-458 ◽  
pp. 511-514
Author(s):  
Bo Zhou ◽  
Xu Kun Li ◽  
Bin Hu

This paper focuses on the thermo-mechanical behaviors of shape memory alloy (SMA) elliptical cross-section rod subjected to torsion deformation. The stress solution in the elliptical cross-section is derived according to linear elastic mechanics. The phase transformation behaviors of the elliptical cross-section rod are described based on the phase transformation model developed by Zhou and Yoon. The phase transformation zone in the elliptical cross-section is numerically determined and discussed.


2011 ◽  
Vol 80-81 ◽  
pp. 22-26
Author(s):  
Bo Zhou ◽  
Shi Cheng Zhao

The temperature memory effect of shape memory alloy (SMA) induced by an incomplete martensitic inverse phase transformation has the potential values in various engineering fields. It is of theoretical and practical interests to establish a phase transformation model which overcomes the limitation that previous phase transformation models of SMA fail to take into account the temperature memory effect. In this paper, the curves of heat flow versus temperature of SMA during the martensitic phase transformation and martensitic inverse phase transformation are described as the quadratic functions of temperature. A new phase transformation model of SMA is developed based on the differential relationship between martensitic volume fraction and phase transformation free energy. Numerical results show that the new model well predicts the phase transformation behaviors of SMA associated with the temperature memory effect.


2012 ◽  
Vol 457-458 ◽  
pp. 409-412
Author(s):  
Bo Zhou ◽  
Tai Yue Yin ◽  
Xu Kun Li

This paper focuses on the thermo-mechanical behaviors of shape memory alloy (SMA) board with a crack subjected to bending load. The stress field near the crack tip of SMA board is described according to the solution of linear elastic mechanics. The phase transformation behaviors of SMA board are formulated based on Zhou’s one-dimensional phase transformation model. The phase transformation zone equation is derived to describe the phase transformation zone near the crack tip.


Author(s):  
Vagner Candido de Sousa ◽  
Tarcísio Marinelli Pereira da Silva ◽  
Carlos De Marqui

This paper presents the modeling, simulation and wind tunnel experimental verification of the aeroelastic behavior of a two-degree-of-freedom (pitch and plunge) typical airfoil section with superelastic shape memory alloy helical springs in the pitch degree-of-freedom. A linearly elastic spring is considered in the plunge degree-of-freedom. Although viscous damping is considered in both degrees-of-freedom, hysteretic damping simultaneously takes place in the pitch degree-of-freedom due to the (stress-induced) pseudoelastic behavior of the shape memory alloy springs. The shape memory alloy phase transformation kinetics and constitutive modeling are based on Brinsons model and the shape memory alloy helical spring behavior is based on classical spring design. The nonlinear effects of shape memory alloy phase transformation are included in the shape memory alloy spring modeling for the representation of hysteretic force-displacement behavior. A two-state linear aerodynamic model is employed to determine the unsteady pitching moment and lift. The aeroelastic behavior of the typical section is numerically and experimentally investigated for different preload levels applied to the shape memory alloys. Numerical predictions and experimental results show that for large enough preload levels (such that shape memory alloy phase transformations take place at small pitch angles) unstable post-flutter regime is replaced by stable limit-cycle oscillations. Moreover, the amplitudes of aeroelastic oscillations decrease with increasing preload levels since more expressive phase transformations are achieved at small pitch angles. Although the amplitudes of the post-flutter limit-cycle oscillations increase with increasing airflow speed (since aerodynamic loads increase with the square of the airflow speed), they remain bounded within acceptable levels over a range of airflow speeds due to hysteretic damping. Moreover, the cutoff airflow speed increases with increasing preload. The experimentally verified results show that the pseudoelastic behavior of shape memory alloy elements can passively enhance the aeroelastic behavior of a typical section.


2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Lei Li ◽  
Qingbin Li ◽  
Fan Zhang

Characteristics of NiTi shape memory alloy (SMA) and its constitutive model with an empirical kinetics equation were investigated in this paper. Firstly, the transformation characters of the NiTi SMA were obtained through a differential scanning calorimetry (DSC) analysis technology, and the properties during incomplete and discontinuous transformation process and the effects of plastic deformation on the transformation were studied. The uniaxial tension, SME, and constrained recovery process of NiTi SMA were examined through an improved 10KN universal material testing machine. Experimental results indicated that the phase transformation characters and the mechanical properties could be affected by the loading process considerably, and the plastic deformation should be taken into account. To simulate the characteristics of NiTi SMA more effectively, a one-dimensional constitutive model derived from the internal variable approach with the consideration of the plastic deformation was constructed based on the DSC and the uniaxial tension experimental results, and a new simple empirical kinetics equation was presented, with the transformation temperature parameters redefined according to the DSC experiment evidence. Comparison between the numerical and experimental results indicated that this constitutive model could simulate the phase transformation characters, the uniaxial tension, SME, and the constrained recovery behavior of NiTi SMA well.


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