scholarly journals Structural material with designed thermal twist for a simple actuation

2022 ◽  
Vol 11 (1) ◽  
pp. 414-422
Author(s):  
Nan Yang ◽  
Yong Deng ◽  
Jinlun Huang ◽  
Xiaodong Niu

Abstract Materials with desired thermal deformation are very important for various engineering applications. Here, a material with the combination of chiral structure and TiNi shape memory alloy (SMA) sheets that performs a twist during heating is proposed. The thermo-mechanical properties of these materials are experimentally investigated. Inspired by this, a car-like material performing translational and rotational motion is designed, which illustrates the potential applications for the next-generation soft robotic devices. Based on this method, one can design remotely manipulated artificial muscles, nanorobots, revolute pairs, and thermal sensors or actuators in a noncontact fashion.

1999 ◽  
Author(s):  
Charles Pfeiffer ◽  
Constantinos Mavroidis ◽  
Kathryn DeLaurentis ◽  
Mike Mosley

Abstract This paper describes the goals and current accomplishments of this research. The main thrust of this effort is to design artificial limbs that are lightweight, compact and dexterous, that mimic human anatomy and maintain a high lifting capability. The key to satisfying these objectives is the use of Shape Memory Alloy (SMA) artificial muscles as actuators. A general methodology to find the placement of SMA wires to achieve desired ranges of motion is presented. Three experimental prototypes, emulating human skeletal structures that are actuated by SMA artificial muscles are described in detail. It is expected that upper extremity amputees will greatly benefit from the commercialization of the novel robot prosthetic devices that will be developed in this research. These lightweight prostheses with high lifting capabilities, force-reflective characteristics and multi-degree of freedom dexterity will tremendously improve the capabilities of amputees and therefore will attract their interest. In addition, our SMA actuated robotic devices can find other commercial applications. Of special interest to our team are two other commercial applications: space robotic systems and robot toys.


Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 80
Author(s):  
Bo Zhang ◽  
Sizhi Zeng ◽  
Fenghua Tang ◽  
Shujun Hu ◽  
Qiang Zhou ◽  
...  

As a stimulus-sensitive material, the difference in composition, fabrication process, and influencing factors will have a great effect on the mechanical properties of a superelastic Ni-Ti shape memory alloy (SMA) wire, so the seismic performance of the self-centering steel brace with SMA wires may not be accurately obtained. In this paper, the cyclic tensile tests of a kind of SMA wire with a 1 mm diameter and special element composition were tested under multi-working conditions, which were pretreated by first tensioning to the 0.06 strain amplitude for 40 cycles, so the mechanical properties of the pretreated SMA wires can be simulated in detail. The accuracy of the numerical results with the improved model of Graesser’s theory was verified by a comparison to the experimental results. The experimental results show that the number of cycles has no significant effect on the mechanical properties of SMA wires after a certain number of cyclic tensile training. With the loading rate increasing, the pinch effect of the hysteresis curves will be enlarged, while the effective elastic modulus and slope of the transformation stresses in the process of loading and unloading are also increased, and the maximum energy dissipation capacity of the SMA wires appears at a loading rate of 0.675 mm/s. Moreover, with the initial strain increasing, the slope of the transformation stresses in the process of loading is increased, while the effective elastic modulus and slope of the transformation stresses in the process of unloading are decreased, and the maximum energy dissipation capacity appears at the initial strain of 0.0075. In addition, a good agreement between the test and numerical results is obtained by comparing with the hysteresis curves and energy dissipation values, so the numerical model is useful to predict the stress–strain relations at different stages. The test and numerical results will also provide a basis for the design of corresponding self-centering steel dampers.


2004 ◽  
Vol 45 (2) ◽  
pp. 272-276 ◽  
Author(s):  
Yun Luo ◽  
Toshiyuki Takagi ◽  
Shintaro Amae ◽  
Motoshi Wada ◽  
Tomoyuki Yambe ◽  
...  

1994 ◽  
Author(s):  
Kuang-Hsi Wu ◽  
Y. Q. Liu ◽  
Michael J. Maich ◽  
Hsien-Kuei Tseng

1999 ◽  
Vol 121 (1) ◽  
pp. 93-97 ◽  
Author(s):  
Kaushik Bhattacharya

Shape-memory Alloys are attractive for many potential applications. In an attempt to provide ideas and guidelines for the development of new shape-memory alloys, this paper reports on a series of investigations that examine the reasons in the crystallography that make (i) shape-memory alloys special amongst martensites and (ii) Nickel-Titanium special among shape-memory alloys.


2008 ◽  
Vol 59 ◽  
pp. 101-107 ◽  
Author(s):  
Rodinei Medeiros Gomes ◽  
Ana Cris R. Veloso ◽  
V.T.L. Buono ◽  
Severino Jackson Guedes de Lima ◽  
Tadeu Antonio de Azevedo Melo

Polycrystalline copper-based shape memory alloys have been of particular interest in relation to Ni-Ti because of their low cost and good shape memory effect. Nevertheless the absence of a pronounced pseudoelasticity effect restricts the number of potential applications. In this work, the influence of Nb and V on the microstructure and the mechanical properties was investigated. Samples of Cu-13.8 Al-Ni containing V and Nb alloy were prepared by induction and solution treated at 850°C and then further quenched into cold water. The addition of Nb and V promotes the formation of precipitates which act as grain refiner and subsequently improve the mechanical properties. The tensile tests were performed at temperatures slightly inferior to Mf and superior to Af, to investigate the shape recovery and pseudoelasticity, respectively. Based on the analyses of the Cu-13,8Al-2Ni-1Nb (wt%) alloy was detected rupture strains greater than 14%, besides observation of the superelasticity of these alloys and quantification of this property by means of cycling, from 0 to strains between 1 and 7%. The studies performed on alloy Cu-13.8Al- 3,5Ni-1V (wt%) made it possible to determine rupture strains in the order of 3% and its superelastic behavior through cycling for deformations between 1 and 3%.


Author(s):  
Veturia Chiroiu ◽  
Ligia Munteanu ◽  
Traian Badea ◽  
Cornel Mihai Nicolescu

The simulation of a flexible finger, actuated with the shape memory alloys (SMAs) artificial muscles, is presented in the paper. The finger is modeled as a cylindrically rod with three embedded NiTi wires in a n aluminum matrix. Forces between NiTi wires causes bending in any plane perpendicular to the longitudinal axis of the finger. The NiTi wires are heated above the austenitic start temperature by passing an electrical current, and the deflected wire tends to return to the initial configuration. Using characteristics of SMAs such as high damping capacity, super-elasticity, thermo-mechanical behavior and shape memory, the actuation for the finger is theoretically introduced and discussed.


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