Improving shape memory alloys for solid-state cooling

Scilight ◽  
2020 ◽  
Vol 2020 (24) ◽  
pp. 241110
Author(s):  
Jodi Ackerman Frank
Keyword(s):  
Solid State ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Solid State Cooling

Phenomenological Models of Solid State Actuators for Network Based System Modelling

2014 ◽  
Author(s):  
Johannes Ziske ◽  
Fabian Ehle ◽  
Holger Neubert
Keyword(s):  
Solid State ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Smart Materials ◽  
Magnetic Flux Density ◽  
System Modelling ◽  
Magnetic Shape Memory ◽  
Magnetic Shape Memory Alloys ◽  
Design And Optimization ◽  
Highly Nonlinear

Smart materials, such as thermal or magnetic shape memory alloys, provide interesting characteristics for new solid state actuators. However, their behavior is highly nonlinear and determined by strong hysteresis effects. This complex behavior must be adequately considered in simulation models which can be applied for efficient actuator design and optimization. We present a new phenomenological lumped element model for magnetic shape memory alloys (MSM). The model takes into account the two-dimensional hysteresis of the magnetic field induced strain as a function of both the compressive stress and the magnetic flux density. It is implemented in Modelica. The model bases on measured limiting hysteresis surfaces which are material specific. An extended Tellinen hysteresis modeling approach is used to calculate inner hysteresis trajectories in between the limiting surfaces. The developed model provides sufficient accuracy with low computational effort compared to finite element models. Thus, it is well suited for system design and optimization based on network models. This is demonstrated with exemplary models of MSM based actuators. System models and simulation results are shown and evaluated for different topologies.

Computational simulations for the development of novel solid-state smart NiTi-Al thermal diodes

2017 ◽  
Vol 28 (15) ◽  
pp. 2082-2094 ◽  
Author(s):  
George N Frantziskonis ◽  
Sourav Gur
Keyword(s):  
Thermal Properties ◽  
Solid State ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Computational Study ◽  
Building Blocks ◽  
Strong Nonlinearity ◽  
Rectification Ratio ◽  
Thermal Rectification ◽  
Niti Shape Memory Alloys

In this study, NiTi shape memory alloys coupled in series with Al are considered as building blocks for thermal diodes. It is shown that the strong nonlinearity in the temperature-dependent thermal properties of NiTi in conjunction with the very different thermal properties of Al can result into a thermal diode of high thermal rectification ratio. As a first level of study, Ni50Ti50 is considered and the effects of various NiTi-Al geometrical configurations, initial temperature, and temperature difference at two ends on the thermal rectification ratio are studied numerically. Within the adopted temperature range (300–400 K, where phase transformation in NiTi occurs), it is shown that NiTi-Al thermal diodes are feasible with rectification ratio up to 4.8, which is quite higher than the ratios in currently known solid-state thermal diodes. This fundamental computational study could provide an important basis and motivation for the development of the next generation of high-temperature solid-state thermal diodes based on smart material such as NiTi shape memory alloys or others.

Investigation of the Kinetic of a Bainitic Reaction upon Heating in a CuAlNiMn and a CuAlNiMnFe Shape Memory Alloy

2013 ◽  
Vol 752 ◽  
pp. 3-9 ◽  
Author(s):  
Marton Benke ◽  
Valéria Mertinger ◽  
Peter Barkoczy
Keyword(s):  
Solid State ◽  
Kinetic Model ◽  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
One Stage ◽  
Shape Memory Behaviour ◽  
Memory Characteristics

The examination of solid state processes leading to the degradation of the shape memory behaviour is essential with respect to the suitability of shape memory alloys. Besides degradation processes occurring during relatively long periods of time called ageing, bainitic reactions that suddenly degrade the shape memory behaviour were also observed in many Cu-based shape memory alloys. The mechanisms and effects of the bainitic reactions on the shape memory characteristics were investigated in many Cu-based systems, but the kinetic of the reaction was not examined so far. In the present paper, an examination was carried out on a CuAlNiMn and a CuAlNiMnFe shape memory alloy to reveal what kinetic model describes the bainitic reaction occurring and thus completely destroying the shape memory effect during one stage of heating.

Magnetic response of porous NiCoMnSn metamagnetic shape memory alloys fabricated using solid-state replication

2012 ◽  
Vol 67 (1) ◽  
pp. 116-119 ◽  
Author(s):  
J.A. Monroe ◽  
J. Cruz-Perez ◽  
C. Yegin ◽  
I. Karaman ◽  
A.B. Geltmacher ◽  
...  
Keyword(s):  
Solid State ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Magnetic Response
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