The Dynamic of an Autoparametrical System With Two Coupled Pendulums Connected by SMA Spring

2008 ◽  
Author(s):  
Danuta Sado ◽  
Krzysztof Gajos
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Equations Of Motion ◽  
Type System ◽  
The Body ◽  
System Response ◽  
Influence Of Temperature ◽  
Influence Of Temperature On ◽  
Resistive Forces ◽  
Sma Spring

The nonlinear dynamics of a three degree of freedom autoparametric system with two pendulums connected by SMA (Shape Memory Alloys) spring in the neighborhood internal and external resonance is presented in this works. The system consists of the body of mass m1 which is hung on a spring and a damper, and two connected by SMA spring pendulums of the length 1 and masses m2 and m3 mounted to the body of mass m1. It is assumed, that the motion of the pendulums are damped by resistive forces. Shape memory alloys have ability to change their material properties, for example stiffness. The equations of motion have been solved numerically and there was studied the influence of temperature on the energy transfer between modes of vibrations. Solutions for the system response are presented for specific values of the parameters of system. It was shown that in this type system one mode of vibrations may excite or damp another mode, and that except different kinds of periodic vibrations there may also appear chaotic vibrations. It depends on various amplitudes of excitation, frequencies ratio and different system parameters. Also fundamental is the influence of temperature on response of the system. For the identification of the responses of the system various techniques, including chaos techniques such as bifurcation diagrams and time histories, power spectral densities (FFT), Poincare` maps and exponents of Lyapunov may be use.

scholarly journals An influence of temperature on reconstructed middle ear with shape memory prosthesis

Meccanica ◽  
2017 ◽  
Vol 53 (8) ◽  
pp. 1959-1980 ◽  
Author(s):  
Rafal Rusinek ◽  
Krzysztof Kecik ◽  
Marcin Szymanski ◽  
Joanna Rekas
Keyword(s):  
Shape Memory ◽  
Middle Ear ◽  
Influence Of Temperature ◽  
Influence Of Temperature On

Influence of Temperature on Field-Induced Reorientation Strain in Magnetic Shape Memory Alloy

2008 ◽  
Vol 575-578 ◽  
pp. 848-853
Author(s):  
Yu Ping Zhu ◽  
Guan Suo Dui
Keyword(s):  
Shape Memory ◽  
Magnetic Shape Memory ◽  
Magnetic Shape Memory Alloys ◽  
Influence Of Temperature ◽  
Single Crystal Specimen ◽  
Magnetic Shape Memory Alloy ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Special Concern ◽  
Theoretical Results

A constitutive model for magnetic shape memory alloys is developed through a combined consideration of micromechanical and thermodynamic theories. Of special concern is the influence of different temperatures on field-induced reorientation strain for a NiMnGa single-crystal specimen. The theoretical results are found to be in general agreement with experimental data. It is shown that the method is accurate and simple.

scholarly journals Experimental Investigation of the Mechanisms and Performance of Active Auxetic and Shearing Textiles

2019 ◽  
Author(s):  
Rachael Granberry ◽  
Brad Holschuh ◽  
Julianna Abel
Keyword(s):  
Experimental Investigation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Smart Materials ◽  
Haptic Feedback ◽  
Axial Stress ◽  
The Body ◽  
Strain Behavior ◽  
Biaxial Tensile Testing ◽  
And Performance

Abstract Anisotropic textiles are commonly used in wearable applications to achieve varied bi-axial stress-strain behavior around the body. Auxetic textiles, specifically those that exhibit a negative Poisson’s ratio (v), likewise exhibit intriguing behavior such as volume increase in response to impact or variable air permeability. Active textiles are traditional textile structures that integrate smart materials, such as shape memory alloys, shape memory polymers, or carbon nanotubes, to enable spatial actuation behavior, such as contraction for on-body compression or corrugation for haptic feedback. This research is a first experimental investigation into active auxetic and shearing textile structures. These textile structures leverage the bending- and torsional-deformations of the fibers/filaments within traditional textile structures as well as the shape memory effect of shape memory alloys to achieve novel, spatial performance. Five textile structures were fabricated from shape memory alloy wire deformed into needle lace and weft knit textile structures. All active structures exhibited anisotropic behavior and four of the five structures exhibited auxetic behavior upon free recovery, contracting in both x- and y-axes upon actuation (v = −0.3 to −1.5). One structure exhibited novel shearing behavior, with a mean free angle recovery of 7°. Temperature-controlled biaxial tensile testing was conducted to experimentally investigate actuation behavior and anisotropy of the designed structures. The presented design and performance of these active auxetic, anisotropic, and shearing textiles inspire new capabilities for applications, such as smart wearables, soft robotics, reconfigurable aerospace structures, and medical devices.

Development of implants from shape memory alloys in dentistry

1999 ◽  
Vol 80 (4) ◽  
pp. 241-246
Author(s):  
M. Z. Mirgazizov
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
The Body ◽  
New Materials ◽  
The World ◽  
Scientific Achievements

The purpose of this speech is to present the main most significant results of our research for almost 20 years in the development and application of shape memory alloys in some areas of dentistry, in particular in implantology. The scientific achievements of Russian scientists in this area are now generally known and recognized in the world as pioneering developments. Over the years, fundamentally new materials and structures implanted into the body have been created, which are similar in behavior to the tissues of the body.

Influence of Temperature on Rate of Regeneration in the Time-graded Regeneration Field in Planarians

Development ◽  
1961 ◽  
Vol 9 (1) ◽  
pp. 159-166
Author(s):  
Agnes Brøndsted ◽  
H. V. Brøndsted
Keyword(s):  
The Body ◽  
Influence Of Temperature ◽  
High Point ◽  
Know How ◽  
Influence Of Temperature On ◽  
Temperature Levels ◽  
Species Specific ◽  
Head Regeneration

There exists in planarians a time-graded regeneration field for head regeneration (Brøndsted, 1946, 1956; A. & H. V. Brøndsted, 1952). The characteristics of this field, expressed by rate of regeneration, are species-specific. The existence of this field ensures harmonious regeneration from cuts everywhere in the body, as a cut will always expose a ‘high point’ where regeneration of a head starts with greatest speed, thus taking the lead in organization and at the same time inhibiting head-forming tendencies elsewhere in the blastema (Brøndsted, 1956). The factors underlying these characteristics of the field are unknown; the problems involved are being attacked from several angles in our laboratory. For the sake of this work it is of some interest to know how the different rates of regeneration at various levels in the time-graded fields might be influenced by various temperature levels. Material and Methods The experiments were carried out on two species differing greatly in the characteristics of their time-graded regeneration fields.

Self-Assembling Swimming Smart Boxes

2014 ◽  
Author(s):  
M. Amin Karami ◽  
Ehsan T. Esfahani ◽  
Mohsen Daghooghi ◽  
Iman Borazjani
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Natural Frequency ◽  
Slight Modification ◽  
The Body ◽  
Mode Shapes ◽  
Primary Mode ◽  
Final Destination ◽  
Self Assembling ◽  
Almost All

This paper presents vibration analysis and structural optimization of a self-assembled structure for swimming. The mode shapes of the structure resemble the body waveform of a swimming Mackerel fish. The lateral deformation waveform of the body of Mackerel is extracted from literature. At higher swimming speeds fish generate the waveform at a higher frequency. Their body waveform stays the same at almost all normal swimming speeds. At the final destination, the box self-assembles using shape memory alloys. The shape memory alloys used for configuration change of the box robot cannot be used for swimming since they fail to operate at high frequencies. MFCs are actuated at the fundamental natural frequency of the structure. This excites the primary mode of resonance. The primary mode of resonance involves rotations of the joints of the robot in the desired fashion. The MFCs are therefore used to indirectly generate the body waveform. We optimize the thickness of the panels and the stiffness of the joints to most efficiently generate the swimming waveforms. Unlike eel we change the speed of the robot by changing the amplitude of the body motions. This is because the frequency of the motion is fixed to the first natural frequency of the robot. The swimming box can swim over the surface and can also swim underwater. With slight modification the boxes can crawl or slither over the land.

scholarly journals Random Vibration Studies of a SDOF System With Shape Memory Restoring Force

1999 ◽  
Author(s):  
Luis Duval ◽  
Mohammad N. Noori ◽  
Zhikun Hou ◽  
Hamid Davoodi ◽  
Stefan Seleecke
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Random Vibration ◽  
Strong Dependence ◽  
Random Excitation ◽  
Restoring Force ◽  
Wide Range ◽  
Force Element ◽  
Sma Spring ◽  
Energy Dissipation Devices

Abstract Intelligent and adaptive material systems and structures have become very important in engineering applications. The basic characteristic of these systems is the ability to adapt to the environmental conditions. One of the new class of materials with promising applications in structural and mechanical systems are Shape Memory Alloys (SMA). The mechanical behavior of shape memory alloys in particular shows a strong dependence on temperature. This property provides opportunities for the utilization of SMAs in actuators or energy dissipation devices. However, the behavior of systems containing shape memory components under random excitation has not yet been addressed in the literature. Such study is important to verify the feasibility of using SMAs in structural systems. In this work a non-deterministic study of the dynamic behavior of a single degree-of-freedom (SDOF) mechanical system, having a Nitinol spring as a restoring force element is presented. The SMA spring is characterized using a one-dimensional phenomenological constitutive model based on the classical Devonshire theory. Response statistics for zero mean random vibration of the SDOF under a wide range of temperature is obtained. Furthermore, nonzero mean analysis of these systems is carried out.

Influence of temperature on the reproduction of Damalinia equi (Denny)

1963 ◽  
Vol 11 (2) ◽  
pp. 183 ◽  
Author(s):  
MD Murray
Keyword(s):  
Skin Temperature ◽  
High Temperatures ◽  
Atmospheric Temperature ◽  
Early Spring ◽  
The Body ◽  
The Sun ◽  
Hair Coat ◽  
Influence Of Temperature ◽  
Influence Of Temperature On

No development of the egg within the female Damalinia equi (Denny) occurred at 16�C. Most eggs were laid at 36�C at R.H.'s of 75% or less, but after an exposure to 44.5�C for only 1 hr females did not lay eggs. Morphogenesis proceeded to an advanced state from 27-39�C, but its completion and the subsequent hatching of the embryo only took place from 31-39�C provided the R.H. was less than 90%. A R.H. of 90% prevented hatching of the eggs. Exposure of eggs to 49�C for 2 hr was lethal. The skin temperature of the horse is influenced considerably by atmospheric temperature. The abundance of D. equi on the bodies of horses in early spring is probably due to the temperatures near the skin of the body being continuously favourable for reproduction of D. equi during the winter. Exposure to the sun can cause the temperatures within the hair coat on the upper aspects of the body to become higher than 44.5�C for more than an hour and thus can retard reproduction. The accumulative effect of repeated high temperatures could prevent an increase in the numbers of D. equi during the summer.

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