Superelastic Behavior under Cyclic Loading for Coil Spring of Ti-Ni Shape Memory Alloy

Sakuma, Toshio; Suzuki, Akihiko

doi:10.2320/matertrans.48.422

Cited by 5 publications

(4 citation statements)

References 12 publications

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“…Even so, the 2D models predict that the spring stiffness is highest when the SMA is in the martensitic phase. This is caused by geometric non-linearities, which have also been observed in the experiments (Enemark et al, 2014; Sakuma and Suzuki, 2007; Savi et al, 2015).…”

Section: Helical Spring Modelsupporting

confidence: 67%

“…Geometrical non-linearities may also be introduced (Enemark et al, 2014; Savi et al, 2015) because SMAs can withstand large strains. This is very clear in some of the force–deflection tests performed by Sakuma and Suzuki (2007) and Savi et al (2015), where the martensitic stiffness appears higher than the austenitic stiffness. Several authors proposed equivalent one-dimensional (1D) models (Aguiar et al, 2010; An et al, 2012; Enemark et al, 2014; Liang and Rogers, 1993), where An et al (2012) also accounted some geometrical non-linearities.…”

Section: Introductionmentioning

confidence: 94%

“…The fabrication and the shape setting of SMA helical springs are described by several authors (Follador et al, 2012; Liu et al, 2008; Sakuma and Suzuki, 2007; Savi et al, 2015; Tobushi et al, 1992). Elahinia et al (2012) described shape setting in relation to medical applications.…”

Section: Experimental Frameworkmentioning

confidence: 99%

“…Therefore, a thermo-mechanical training process is required to get repeatable and stabilised behaviour. The transient training period comprises a number of loading cycles in the order of 100–400 depending on the material, its thermal treatment (shape setting) and the mechanical loading (Morin et al, 2011; Sakuma and Suzuki, 2007; Tobushi et al, 1992; Wolons et al, 1998). When the SMA element is stabilised, the dissipation capability as well as the average stiffness during a loading cycle depends on the loading amplitude, the ambient temperature and the loading rate.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Modelling, characterisation and uncertainties of stabilised pseudoelastic shape memory alloy helical springs

Enemark¹,

Santos²,

Savi

2016

Journal of Intelligent Material Systems and Structures

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The thermo-mechanical behaviour of pseudoelastic shape memory alloy helical springs is of concern discussing stabilised and cyclic responses. Constitutive description of the shape memory alloy is based on the framework developed by Lagoudas and co-workers incorporating two modifications related to hardening and sub-loop functions designated by Bézier curves. The spring model takes into account both bending and torsion of the spring wire, thus representing geometrical non-linearities. Simplified models are explored showing that a single point in the wire cross section is enough to represent the global spring behaviour in spite of complex stress–strain distributions. The experiments are carried out considering different deflection amplitudes, frequencies and ambient temperatures, which influence the spring behaviour to different extents. The model is fitted against a calibration data set resulting in 1.3% residual standard deviation relative to the full range force. Compared to the validation data set, the errors are below 10% relative to the full range of the complex modulus. Uncertainty analysis of the model parameters using a Markov chain Monte Carlo technique shows low to high parameter correlation, and the relative uncertainties are less than ±12%. Both the heat capacity and the convection coefficient are clearly identifiable from the performed experiments.

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Section: Helical Spring Modelsupporting

confidence: 67%