On a Finger Model Actuated With Shape Memory Alloy Artificial Muscles

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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Shape Memory Alloy As Artificial Muscles for Facial Prosthesis

Volume 3: Biomedical and Biotechnology Engineering ◽

10.1115/imece2017-71621 ◽

2017 ◽

Author(s):

Paul Mazza ◽

Moochul Shin ◽

Anthony Santamaria

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Response Times ◽

Electrical Current ◽

Artificial Muscles ◽

Elliptical Equation ◽

Facial Motion ◽

Facial Prosthesis ◽

Nitinol Wire ◽

Original Length

Facial paralysis affects hundreds of thousands of people each year; a common result of infection, trauma, stroke, and Bell’s palsy, among others. Achieving facial prosthetics that are lightweight, comfortable, aesthetically pleasing, energy efficient, and that allow human-like facial motion is a challenge. This study focuses on examining the feasibility of the use of a shape memory alloy as a means of low-power artificial muscles. Nitinol is a shape memory alloy (SMA) that can recover up to four percent of its original length when exposed to either a large enough change in temperature which can be controlled via electrical current or a stress. In this work, human eyelid muscles are replicated using Nitinol embedded in silicon. Silicone is used due to its elasticity, texture, flexibility, compatibility and ease of manufacturing. A mold is created based on human facial geometry around the orbital using a 3D printer. Based on average human eyelid dimensions, as well as the contraction properties of the Nitinol wire, an elliptical equation is used determine the length of wire required to completely close the eyelid from an open position. Temperature change of the system is controlled by modulating current through the resistive Nitinol wire. The contraction and expansion times of the eyelids are measured. The circuit is then optimized so that response times mimicked that of the human eyelid. Finally, based on the amount of times the average human blinks, the average daily power consumption is calculated. Future directions including miniaturization of the control system, bonding between SMA wires and silicone, and energy management are discussed.

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Shape Memory Alloy Artificial Muscles for Treatments of Fecal Incontinence

MATERIALS TRANSACTIONS ◽

10.2320/matertrans.45.272 ◽

2004 ◽

Vol 45 (2) ◽

pp. 272-276 ◽

Cited By ~ 1

Author(s):

Yun Luo ◽

Toshiyuki Takagi ◽

Shintaro Amae ◽

Motoshi Wada ◽

Tomoyuki Yambe ◽

...

Keyword(s):

Fecal Incontinence ◽

Shape Memory Alloy ◽

Shape Memory ◽

Artificial Muscles

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Effect of Nd Addition on the Microstructure and Martensitic Transformation of Ni-Ti Shape Memory Alloys

Advances in Materials Science and Engineering ◽

10.1155/2014/489701 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6 ◽

Cited By ~ 6

Author(s):

M. Dovchinvanchig ◽

C. W. Zhao ◽

S. L. Zhao ◽

X. K. Meng ◽

Y. J. Jin ◽

...

Keyword(s):

Rare Earth ◽

Martensitic Transformation ◽

Shape Memory Alloy ◽

Shape Memory ◽

Earth Element ◽

Transformation Behavior ◽

Nd Addition ◽

One Step ◽

Niti Matrix ◽

Start Temperature

The effect of rare earth element Nd addition on the microstructure and martensitic transformation behavior of Ni50Ti50−xNdx(x=0, 1, 3, 7, 20) shape memory alloy was investigated experimentally. The results showed that the microstructure of Ni-Ti-Nd ternary alloy consists of the NiNd phase and the NiTi matrix. One-step martensitic transformation was observed in all alloys. The martensitic transformation start temperatureMsincreased gradually with increasing Nd content for Ni-Ti-Nd alloys.

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Rate-Dependent Damping Capacity of NiTi Shape Memory Alloy

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.172-174.37 ◽

2011 ◽

Vol 172-174 ◽

pp. 37-42 ◽

Cited By ~ 2

Author(s):

Yong Jun He ◽

Qing Ping Sun

Keyword(s):

Shape Memory Alloy ◽

Strain Rate ◽

Shape Memory ◽

Strain Curve ◽

Tensile Loading ◽

Niti Shape Memory Alloy ◽

Damping Capacity ◽

Environmental Condition ◽

Mechanical Coupling ◽

Rate Dependent

High damping capacity is one of the prominent properties of NiTi shape memory alloy (SMA), having applications in many engineering devices to reduce unwanted vibrations. Recent experiments demonstrated that, the hysteresis loop of the stress-strain curve of a NiTi strip/wire under a tensile loading-unloading cycle changed non-monotonically with the loading rate, i.e., a maximum damping capacity was obtained at an intermediate strain rate (ε.critical). This rate dependence is due to the coupling between the temperature dependence of material’s transformation stresses, latent-heat release/absorption in the forward/reverse phase transition and the associated heat exchange between the specimen and the environment. In this paper, a simple analytical model was developed to quantify these thermo-mechanical coupling effects on the damping capacity of the NiTi strips/wires under the tensile loading-unloading cycle. We found that, besides the material thermal/mechanical properties and specimen geometry, environmental condition also affects the damping capacity; and the critical strain rate ε.criticalfor achieving a maximum damping capacity can be changed by varying the environmental condition. The theoretical predictions agree quantitatively with the experiments.

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Design of Shape Memory Alloy Springs With Applications in Vibration Control

Journal of Vibration and Acoustics ◽

10.1115/1.2930305 ◽

1993 ◽

Vol 115 (1) ◽

pp. 129-135 ◽

Cited By ~ 44

Author(s):

C. Liang ◽

C. A. Rogers

Keyword(s):

Shape Memory Alloy ◽

Shape Memory Alloys ◽

Shape Memory ◽

Vibration Control ◽

Young’S Modulus ◽

Young's Modulus ◽

Design Method ◽

Control Area ◽

Spring Constant ◽

Damping Capacity

Shape memory alloys (SMAs) have several unique characteristics, including their Young’s modulus-temperature relations, shape memory effects, and damping characteristics. The Young’s modulus of the high-temperature austenite of SMAs is about three to four times as large as that of low-temperature martensite. Therefore, a spring made of shape memory alloy can change its spring constant by a factor of three to four. Since a shape memory alloy spring can vary its spring constant, provide recovery stress (shape memory effect), or be designed with a high damping capacity, it may be useful in adaptive vibration control. Some vibration control concepts utilizing the unique characteristics of SMAs will be presented in this paper. Shape memory alloy springs have been used as actuators in many applications although their use in the vibration control area is very recent. Since shape memory alloys differ from conventional alloy materials in many ways, the traditional design approach for springs is not completely suitable for designing SMA springs. Some design approaches based upon linear theory have been proposed for shape memory alloy springs. A more accurate design method for SMA springs based on a new nonlinear thermomechanical constitutive relation of SMA is also presented in this paper.

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