905 A Computer Simulation for Shape Memory Effect using Constitutive Model for Accommodation of Transformation Strain

2010 ◽  
Vol 2010 (0) ◽  
pp. 520-521
Author(s):  
Hiroki CHO ◽  
Takaei YAMAMOTO ◽  
Akihiko SUZUKI ◽  
Toshio SAKUMA
Keyword(s):  
Computer Simulation ◽  
Constitutive Model ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Transformation Strain

A Constitutive Model for Shape Memory Alloys Involving Transformation, Reorientation and Plasticity

2013 ◽  
Vol 535-536 ◽  
pp. 105-108
Author(s):  
Xiang He Peng ◽  
Min Mei Chen ◽  
Jun Wang
Keyword(s):  
Plastic Deformation ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Volume Fraction ◽  
Transformation Rule ◽  
Constitutive Behavior ◽  
Plastic Parts

A constitutive model is developed for shape memory alloys (SMAs) based on the concept that an SMA is a mixture composed of austenite and martensite. The deformation of the martensite is separated into elastic, thermal, reorientation and plastic parts, and that of the austenite is separated into elastic, thermal and plastic parts. The volume fraction of each phase is determined with the modified Tanaka’s transformation rule. The typical constitutive behavior of some SMAs, including pseudoelasticity, shape memory effect, plastic deformation as well as its effects, is analyzed.

Martensitic Transformation and Shape Memory Effect of Ni53.25Mn21.75Ga25 Ferromagnetic Shape Memory Alloy

2012 ◽  
Vol 476-478 ◽  
pp. 1504-1507
Author(s):  
Hai Bo Wang ◽  
Shang Shen Feng ◽  
Pei Yang Cai ◽  
Yan Qiu Huo
Keyword(s):  
Magnetic Field ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Parent Phase ◽  
Transformation Strain ◽  
Scanning Calorimetry ◽  
Reversible Transformation ◽  
Ferromagnetic Shape Memory

The martensitic transformation, crystalline structure, microstructure and shape memory effect of the Ni53.25Mn21.75Ga25 (at.%) alloy are investigated by means of Differential Scanning Calorimetry (DSC), X-ray diffraction (XRD), Transmission Electron Microscope (TEM) and the standard metal strain gauge technique. The XRD results showed that the Ni53.25Mn21.75Ga25 alloy is composed of cubic parent phase at room temperature. TEM observation proved that the typical twin martensite is tetragonal structure and tweed-like contrast which is typical image for the parent phase. A large reversible transformation strain, about 0.54%, is obtained in this undeformed polycrystalline alloy due to martensitic transformation and its reverse transformation. This transformation strain is also increased to 0.65% by the external magnetic field. It is believed that the effect of the magnetic field on the preferential orientation of martensitic variants increases the transformation strain.

Conventional Plasticity Constitutive Model for Shape Memory Alloys

2011 ◽  
Vol 216 ◽  
pp. 469-473
Author(s):  
Hai Tao Li ◽  
Xiang He Peng
Keyword(s):  
Shape Memory Alloy ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Numerical Algorithm ◽  
Individual Behavior ◽  
Two Phase ◽  
The Individual

A two-phase constitutive model for shape memory alloys (SMAs) is proposed based on the fact that SMAs is dynamically composed of austenite and martensite. The behavior of SMAs is regarded as the dynamic combination of the individual behavior of each phase. This model can describe the main characteristics of SMAs, such as pseudoelasticity and shape memory effect. The corresponding numerical algorithm was also developed to describe the main features of shape memory alloy Au-47.5at.%Cd.

A Multidimensional Constitutive Model for Shape Memory Alloys

2014 ◽  
Vol 584-586 ◽  
pp. 1141-1144
Author(s):  
Wei Wang ◽  
Ji Yuan Liu
Keyword(s):  
Free Energy ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Dissipation Energy ◽  
Thin Walled

A multidimensional constitutive model for shape memory alloys (SMA) is developed in the paper, which is based on the thermodynamics theories of free energy and dissipation energy. This model can well describe both the shape memory effect (SME) and super elasticity effect (SE) of the thin-walled SMA cylinder under an axial tensional force and torsion.

scholarly journals Evaluation of the Shape Memory Effect by Micro-Compression Testing of Single Crystalline Ti-27Nb Ni-Free Alloy

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 110 ◽  
Author(s):  
Takashi Nagoshi ◽  
Takahisa Yasuda ◽  
Nao Otaki ◽  
Masaki Tahara ◽  
Hideki Hosoda ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Transformation Strain ◽  
Orientation Dependence ◽  
Compression Tests ◽  
Temperature Dependent ◽  
Single Crystalline ◽  
Aspect Ratios ◽  
Transformation Stress

In this work, micro-compression tests are performed at various temperatures with Ti-27Nb (at.%) single crystalline pillars to investigate anisotropic deformation behavior, including the shape memory effect. In non-tapered single-crystal pillars with loading directions parallel to [001], [011], and [111], transformation strain and stress show orientation dependence. [001]-oriented micropillars with aspect ratios of 2 and 1.5 demonstrate temperature-dependent transformation stress during micro-compression at various temperatures. Although more stress is required to induce martensite transformation in the pillar with the lower aspect ratio, the temperature dependence of ~1.8 MPa/K observed in both pillars is in good agreement with that of bulk Ti-27Nb.

Martensitic Transformation and Shape Memory Effect in Titanium-Gold Compound

2011 ◽  
Vol 172-174 ◽  
pp. 49-54 ◽  
Author(s):  
Charles Declairieux ◽  
Philippe Vermaut ◽  
Richard Portier ◽  
Patrick Ochin ◽  
Anne Denquin
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Niti Alloy ◽  
Transformation Strain ◽  
Gold Compound ◽  
Compression Tests ◽  
Recoverable Strain ◽  
Ternary Element

High temperature shape memory alloys offer numerous potential applications in industrial domains like aeronautics. Even if up to now, none of the studied alloys have found a place in airplane turbines, research in this field is still active. Starting from the well-known “room temperature” shape memory alloy NiTi, it has been demonstrated that the addition of a ternary element such as gold in substitution of nickel greatly enhances the temperatures of the martensitic transformation. In the binary TiAu compound, the martensite start temperature can attain 875 K with satisfying reversibility and cycling stability. From lattice parameters measurements, it has been shown that the maximum transformation strain can reach 10.75 % for Ti47Au53alloy, which is comparable to that of the NiTi alloy. However, to the best of our knowledge, quantitative measurements of the recoverable strain by shape memory effect are not available in the literature. We present here some quantitative results of shape memory effect associated to this phase transformation in Titanium-Gold alloys measured after compression tests.

A Viscoelastic-Plastic Constitutive Model of Shape Memory Polymer

2019 ◽  
Vol 35 (5) ◽  
pp. 601-611 ◽  
Author(s):  
Xueyao Zheng ◽  
Bo Zhou ◽  
Shifeng Xue
Keyword(s):  
Constitutive Model ◽  
Stationary Phase ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Shape Memory Polymer ◽  
Memory Process ◽  
Mechanical Behaviors ◽  
Reversible Phase ◽  
Flow Element

ABSTRACTIt is of practical significance to develop a constitutive model which is able to predict the thermomechanical behaviors of the shape memory effect occurring in a shape memory polymer (SMP) accurately. The mechanism of shape memory effect of SMP is explained based on the assumption that SMP is composed by two phases, reversible phase and stationary phase. Especially the different flow elements are respectively added to the reversible phase and stationary phase in order to express the plastic behavior of SMP. There are two springs in series, one dashpot and one flow element in the reversible phase. There are two springs in parallel, one dashpot and one flow element in the stationary phase. A constitutive equation is developed to express the thermo-mechanical behaviors of shape memory effect in the SMP based on viscous-elastic mechanics and plastic theory. An internal variable, frozen ratio, is defined to follow the shape memory process in SMP, and the material properties are described as the functions of frozen ratio based on phase transition theorem. The developed constitutive model, which includes above constitutive equation and material parameter functions, is used to numerically simulate the thermo-mechanical behaviors of SMP under various load cycles. Results show that the developed constitutive model can not only predict the shape memory process of SMP accurately, but also express the rate-dependent behaviors of SMP effectively.

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