Asymmetrical Bending Model for NiTi Shape Memory Wires: Numerical Simulations and Experimental Analysis

Flor, Silvia De la; Urbina, C.; Ferrando, Francesc

doi:10.1111/j.1475-1305.2009.00679.x

Cited by 27 publications

(13 citation statements)

References 24 publications

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“…This effect has been predicted by several SMA beam models (e.g. De la Flor et al, 2010). Experimentally, Rejzner et al (2002) inferred the neutral axis position using strain gages on the top and bottom of a SMA beam, but here DIC allows Y 0 to be measured directly for the first time.…”

Section: Bending Experimentsmentioning

confidence: 73%

“…Despite the myriad of applications that employ superelastic SMA in bending, and despite the number of SMA bending models (we found 13) (Atanacković and Achenbach, 1989;Thier et al, 1991;Pelton et al, 1994;Plietsch et al, 1994;Berg, 1995b;Auricchio and Sacco, 1997;Raniecki et al, 2001;Rejzner et al, 2002;Purohit and Bhattacharya, 2002;Liew et al, 2004;Rajagopal and Srinivasa, 2005;Buratti, 2005;De la Flor et al, 2010), few careful pure-bending experiments exist in the literature. Traditional 4-point bending fixtures operate under the assumptions of small beam displacements and rotations, which are easily violated when used with slender SMA specimens.…”

Section: Introductionmentioning

confidence: 82%

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Tension, compression, and bending of superelastic shape memory alloy tubes

Reedlunn

Churchill

Nelson

et al. 2014

Journal of the Mechanics and Physics of Solids

176

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While many uniaxial tension experiments of shape memory alloys (SMAs) have been published in the literature, relatively few experimental studies address their behavior in compression or bending, despite the prevalence of this latter deformation mode in applications. In this study, superelastic NiTi tubes from a single lot of material were characterized in tension, compression, and pure bending, which allowed us to make direct comparisons between the deformation modes for the first time. Custom built fixtures were used to overcome some long-standing experimental difficulties with performing well-controlled loading and accurate measurements during uniaxial compression (avoiding buckling) and large-rotation bending. In all experiments, the isothermal, global, mechanical responses were measured, and stereo digital image correlation (DIC) was used to measure the evolution of the strain fields on the tube's outer surface.As is characteristic of textured NiTi, our tubes exhibited significant tension-compression asymmetry in their uniaxial responses. Stress-induced transformations in tension exhibited flat force plateaus accompanied by strain localization and propagation. No such localization, however, was observed in compression, and the stress "plateaus" during compression always maintained a positive tangent modulus. While our uniaxial results are similar to the observations of previous researchers, the DIC strain measurements provided details of localized strain behavior with more clarity and allowed more quantitative measurements to be made. Consistent with the tension-compression asymmetry, our bending experiments showed a significant shift of the neutral axis towards the compression side. Furthermore, the tube exhibited strain localization on the tension side, but no localization on the compression side during bending. This is a new observation that has not been explored before. Detailed analysis of the strain distribution across the tube diameter revealed that the traditional assumption of elementary beam theory, that plane sections remain plane, does not hold. Yet when the strain was averaged over a few diameters of axial length, the tensile and compressive responses input into elementary beam theory predicted the global bending response with reasonable accuracy. While it is encouraging that a simple model could predict the moment-curvature response, we recommend that beam theory be used with caution. The averaged strain field can under/over predict local strains by as much as two-fold due to the localized deformation morphology.

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Section: Bending Experimentsmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 82%

Tension, compression, and bending of superelastic shape memory alloy tubes

Reedlunn

Churchill

Nelson

et al. 2014

Journal of the Mechanics and Physics of Solids

176

View full text Add to dashboard Cite

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“…Tables 1 and 2 enumerate the adopted material parameters in experiments conducted by Gall et al (1999) (it will be referred as M 1 ) and Gillet et al (1998) (it will be referred as M 2 ), respectively. Also, Table 3 enumerates the properties of materials chosen by Flor et al for experiments (De la Flor et al, 2011) (it will be referred as M 3 ). It is notable that we employ these material parameters which are chosen by Poorasadion et al (2014) to simulate the porous SMA beam.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…These effects include the tension–compression asymmetric behavior and the effect of internal sub-loops. Poorasadion et al (2014) presented a modified version of Brinson’s model which takes advantage of experimental tests and modifications discussed in Chung et al (2006), De la Flor et al (2011), and Khandelwal and Buravalla (2008) to improve the original Brinson’s model in terms of transformation kinetics functions and accounting for the asymmetric behavior. A comprehensive explanation of this model is presented in Poorasadion et al (2014) work and also in Fahimi et al (2019a, 2019b) and Nassiri-monfared et al (2018), but to summarize the main equations of modified model, first the Hooke’s law must be mentioned here…”

Section: Ibm Reviewmentioning

confidence: 99%

Asymmetric bending response of shape memory alloy beam with functionally graded porosity

Fahimi

Hajarian

Eskandari

et al. 2020

Journal of Intelligent Material Systems and Structures

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In this study, an innovative semi-analytical model is presented to simulate the bending behavior of a shape memory alloy porous beam throughout loading and unloading cycles. The basis of the proposed method is the improved Brinson model which can capture the asymmetry behaviors of shape memory alloys in tension and compression. The comparison of the semi-analytical solution with two-dimensional finite element analysis results for both symmetric and asymmetric models of a homogeneous shape memory alloy beam is presented for model validation. Afterward, bending analysis of shape memory alloy beams with uniform porosity and functionally grading porosity is studied. For this purpose, first, the bending analysis of a shape memory alloy beam with uniform porosity is investigated to show the effects of porosity coefficient on the free tip deflection and slope. Then, the bending analysis of a shape memory alloy beam with functionally grading porosity is simulated. Reported findings with respect to symmetric and asymmetric models indicate that raising the porosity coefficient brings about an increase in deflection and slope. Also, it highlights the significant difference between the results of the asymmetric and symmetric models. The proposed semi-analytical solution can be utilized as an efficient tool for studying the effects of changing any of the porosity coefficient, the geometry, and material of shape memory alloy beams.

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“…The problem of bending of a SMA beam was investigated numerically by many authors by means of finite element simulation, for example, Auricchio and Sacco (1997), Auricchio et al (2011), and Poorasadion et al (2015) or by numerical procedures based on the partition of the beam cross-section into a number of thin layers (De la Flor et al, 2011). Analytical approaches have been also tempted by some authors, but they are limited to a loading-unloading cycle and have never been extend to reversed loading.…”

Section: Introductionmentioning

confidence: 99%

Analytical modeling of the shape memory effect in SMA beams with rectangular cross section under reversed pure bending

Radi

2021

Journal of Intelligent Material Systems and Structures

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An analytical model is developed for a prismatic SMA beam with rectangular cross section subjected to alternating bending at temperature below the austenitic transformations. The loading path consists in a loading-unloading cycle under bending and then under reversed bending. Two opposite martensitic variants take place, whose volume fractions evolve linearly with the axial stress. Different Young’s moduli are taken for the austenitic and martensitic phases. As the bending moment is increased, the martensitic transformation starts from the top and bottom and then it extends inwards. If the maximum applied bending moment is large enough, then the complete Martensitic transformation takes place at the upper and lower parts of the cross section. During unloading and the following reversed bending, reorientation of the Martensite variant into the opposite one takes place starting from the boundary between the fully martensitic region and the intermediate transforming region. Special attention is devoted to calculate analytically the axial stress and Martensite variant distributions within the cross section at each stage of the process. A closed form moment-curvature relation is provided for loading and elastic unloading and in integral form for the rest of the process. The approach is then validated by comparison with analytical results available in the literature.

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Asymmetrical Bending Model for NiTi Shape Memory Wires: Numerical Simulations and Experimental Analysis

Cited by 27 publications

References 24 publications

Tension, compression, and bending of superelastic shape memory alloy tubes

Tension, compression, and bending of superelastic shape memory alloy tubes

Asymmetric bending response of shape memory alloy beam with functionally graded porosity

Analytical modeling of the shape memory effect in SMA beams with rectangular cross section under reversed pure bending

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