Modelling, Prototype Construction and Testing of Helical Shape Memory Springs With Hollow Cross-Section

2009 ◽  
Author(s):  
Igor Spinella ◽  
Eugenio Dragoni ◽  
Francesco Stortiero
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Cross Section ◽  
Helical Spring ◽  
Lower Mass ◽  
Hollow Section ◽  
Sma Actuators ◽  
Helical Springs ◽  
High Bandwidth ◽  
Sma Helical Spring

Shape memory alloys (SMAs) are used in many applications as actuators. The main drawbacks that limit the use of the SMAs in the field of micro-actuation are the low bandwidth and the unsatisfactory stroke. This paper contributes to enhancing the performances of SMA actuators by proposing a new SMA helical spring with hollow section. The hollow spring is modelled, then it is constructed and finally it is tested, comparing its performances with those of a spring with solid cross-section of equal stiffness and strength. Emptied of the inefficient material from its centre, the hollow spring features a lower mass (37% less) and an extremely lower cooling time (four times less). These results demonstrate that helical springs with hollow construction can be successfully exploited to realize SMA actuators with high bandwidth and stroke.

Modeling, Prototyping, and Testing of Helical Shape Memory Compression Springs With Hollow Cross Section

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Igor Spinella ◽  
Eugenio Dragoni ◽  
Francesco Stortiero
Keyword(s):  
Shape Memory ◽  
Cross Section ◽  
Helical Spring ◽  
Lower Mass ◽  
Hollow Section ◽  
Sma Actuators ◽  
Helical Springs ◽  
Compression Springs ◽  
Sma Helical Spring ◽  
Mechanical Actuation

Shape memory alloys (SMAs) are used in many applications as actuators. The main drawbacks that limit the use of the SMAs in the field of mechanical actuation are the low mechanical bandwidth (up to a few Hertzs) and the unsatisfactory stroke (several millimeters). This paper contributes to enhancing the performances of SMA actuators by proposing a new SMA helical spring with a hollow section. The hollow spring is modeled, then it is constructed, and finally it is tested in compression to compare its performances with those of a spring with a solid cross section of equal stiffness and strength. Emptied of the inefficient material from its center, the hollow spring features a lower mass (37% less) and an extremely lower cooling time (four times less) than its solid counterpart. These results demonstrate that helical springs with a hollow construction can be successfully exploited to build SMA actuators for higher operating frequencies and improved strokes.

Shape Memory Alloys in Automotive Applications

2014 ◽  
Vol 663 ◽  
pp. 248-253 ◽  
Author(s):  
Jaronie Mohd Jani ◽  
Martin Leary ◽  
Aleksandar Subic
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
External Force ◽  
Active Element ◽  
Mechanical Design ◽  
Competitive Market ◽  
Automotive Applications ◽  
Market Prices ◽  
Sma Actuators

Shape memory alloy (SMA) actuators have drawn much attention and interest due to their unique and superior properties, and are expected to be equipped in many modern vehicles at competitive market prices. The key advantage is that SMA actuators do not require bulky and complicated mechanical design to function, where the active element (e.g. SMA wire or spring) can be deformed by applying minimal external force and will retain to their previous form when subjected to certain stimuli such as thermomechanical or magnetic changes. This paper describes the SMA attributes that make them ideally suited as actuators in automotive applications and to address their limitations, feasibilities and prospects.

Evaluation of radiation interaction parameters of some shape memory alloys

Kerntechnik ◽  
2021 ◽  
Vol 86 (5) ◽  
pp. 382-386
Author(s):  
S. Tekerek ◽  
E. Yıldız
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Cross Section ◽  
Atomic Number ◽  
Effective Atomic Number ◽  
Interaction Parameters ◽  
Photon Intensity ◽  
Chemical Constitution

Abstract In this study, effective atomic number (Zeff), atomic (σta) and electronic cross section (σte) values of some shape memory alloys (SMA) were calculated at energies 5.9, 6.1, 8, 11.2, 25, 59.543, 75, 112, 149 keV. It has been observed that the obtained values of the calculated parameters vary depending on the photon intensity, chemical constitution and density of the alloys. Calculations were made using the WinXCom program and the graph of the change according to the energy of the obtained results was drawn. The results of this study are thought to be beneficial in the application of various fields.

Design of Active Bias Sma Actuators for Morphing Wing Applications

2011 ◽  
Vol 409 ◽  
pp. 627-632 ◽  
Author(s):  
Thomas Georges ◽  
Vladimir Brailovski ◽  
Patrick Terriault
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Active Element ◽  
Mechanical Systems ◽  
Morphing Wing ◽  
Sma Actuators ◽  
Active Elements ◽  
Sma Actuator

Shape Memory Alloys (SMAs) can provide compact and effective actuation for a variety of mechanical systems. Generally speaking, SMA-driven actuator systems can be divided into three subsystems: a) SMA active element, b) the transmission and c) a bias element. In respect to the type of bias, two actuator configurations can be distinguished: passive bias actuators where the SMA active element is coupled with an elastic bias element (spring), and active bias actuators in which two SMA active elements are connected together. This work is focused on designing an SMA actuator using active bias elements for morphing wing applications. Keywords: SMA actuator, active bias, antagonist, design, morphing wing

Helical Springs of Hollow Circular Cross Section

1959 ◽  
Vol 81 (1) ◽  
pp. 30-35
Author(s):  
C. W. Bert
Keyword(s):  
Experimental Investigation ◽  
Elasticity Theory ◽  
Cross Section ◽  
Circular Cross Section ◽  
Shear Stresses ◽  
Helical Spring ◽  
Circular Section ◽  
Helical Springs ◽  
Elastic Shear ◽  
Theory Solution

A theoretical and experimental investigation of elastic shear stresses and deflection in an axially loaded helical spring having a hollow circular section is reported in this paper. Two analyses are presented: An approximation of the stresses by strength-of-materials theory and a more accurate elasticity-theory solution for stresses and deflection. The results are compared with strain and deflection measurements on an actual tubular spring.

scholarly journals Behaviour of NiTi SMA Helical Springs under Different Temperatures and Deflections

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
R. Santhanam ◽  
Y. Krishna ◽  
M. S. Sivakumar
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Shape Recovery ◽  
Scanning Calorimetry ◽  
Helical Springs ◽  
Heating And Cooling ◽  
Niti Sma ◽  
Different Temperatures ◽  
Sma Spring ◽  
Sma Helical Spring

Shape memory alloys (SMAs) are one of the most widely used smart materials in many applications because of their shape memory effect property. In this work, the behaviour of NiTi SMA helical spring was evaluated through isothermal force-displacement experiment (IFDE) and shape recovery force experiment (SRFE). The transformation temperatures of SMA spring were determined by differential scanning calorimetry (DSC) test. In situ heating of SMA spring by direct electric current was used instead of conventional furnace heating. The continuous measurement of temperature of SMA spring during heating and cooling was ensured with attaching the thermocouple by heat shrinkable sleeve. From IFDE, the force-deflection behaviour under different constant temperatures and from SRFE and the force-temperature behaviour under different constant deflections are obtained. The results of IFDE show that the force increases and the residual displacement decreases with an increase in the temperature, and the stiffness of the spring at austenite state is greater than that at martensitic state. The results of SRFE show that the shape recovery force increases more or less linearly with an increase in the initial deflection for the same temperature range. But the shape recovery forces are not similar during heating and cooling stages. This paper presents the experimental setup, experimental procedures, and the observed behaviour of SMA helical springs under different temperatures and deflections.

Texture in NiTi-Based Shape Memory Alloys Produced by Twin Roll Casting

2013 ◽  
Vol 203-204 ◽  
pp. 101-104 ◽  
Author(s):  
Tomasz Goryczka ◽  
Patrick Ochin
Keyword(s):  
Chemical Composition ◽  
Heat Flow ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Cross Section ◽  
Solidification Rate ◽  
Casting Technique ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Twin Roll

Two shape memory alloys with nominal chemical composition: Ni50Ti50 and Ni47Ti50Co3 were produced using twin roll casting technique (TRC). Relatively high cooling rate realized during solidification causes directional heat flow. In result of that, high textured strips were produced. However, the total amount of the preferentially oriented grains differs between surface and cross-section of the strip. At surface, where the crystallization of the grains is the most intensive amount of the grains can reach about 77%. At the cross-section of both strips, where the solidification rate decreased, the total amount of the textured grains was not higher than 57%.

Atomic Order and Martensitic Transformation in Cu-Al-Be Shape Memory Alloys

1995 ◽  
Vol 05 (C8) ◽  
pp. C8-973-C8-978
Author(s):  
M. Jurado ◽  
Ll. Mañosa ◽  
A. González-Comas ◽  
C. Stassis ◽  
A. Planes
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Atomic Order
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