scholarly journals A New Approach to the Design of Helical Shape Memory Alloy Spring Actuators

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Esuff Khan ◽  
Sivakumar M. Srinivasan
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Design Procedure ◽  
Transformation Strain ◽  
Design Approach ◽  
Temperature Phase ◽  
Helical Springs ◽  
Traditional Design ◽  
Residual Deformations ◽  
Sma Spring

Shape memory alloys (SMAs) are smart materials that have the ability to recover their original shape by eliminating residual deformations, when subjected to adequate temperature rise (Shape memory effect). This special behavior attracts the use of SMAs as efficient stroke/force actuators. Most of the engineering applications require helical springs as actuators and proper design of SMA helical spring actuators is very important. In the traditional design approach of SMA spring (Waram, 1993), only strain between linear zones was considered in order to simplify the design and to improve the fatigue life. Only modulus difference between high-temperature and low-temperature phase was utilized, and the transformation strain was not considered as the total transformation strain will be more and will degrade the performance of actuator. In the present design, we have shown that transformation strain can be restricted by using hard stops and the partial transformation strain can be used to improving the capacity of SMA spring actuator. A comparison of the traditional design approach of SMA spring and the proposed design procedure has been made to give an idea of its effect on the design and the related parameters.

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.

Shape memory alloy–actuated prestressed composites with application to morphing automotive fender skirts

2018 ◽  
Vol 30 (3) ◽  
pp. 479-494 ◽  
Author(s):  
Venkata Siva C Chillara ◽  
Leon M Headings ◽  
Ryohei Tsuruta ◽  
Eiji Itakura ◽  
Umesh Gandhi ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Smart Materials ◽  
Design Procedure ◽  
Building Blocks ◽  
Smart Composite ◽  
Thermally Induced ◽  
One Dimensional ◽  
Flat Shape

This work presents smart laminated composites that enable morphing vehicle structures. Morphing panels can be effective for drag reduction, for example, adaptive fender skirts. Mechanical prestress provides tailored curvature in composites without the drawbacks of thermally induced residual stress. When driven by smart materials such as shape memory alloys, mechanically-prestressed composites can serve as building blocks for morphing structures. An analytical energy-based model is presented to calculate the curved shape of a composite as a function of force applied by an embedded actuator. Shape transition is modeled by providing the actuation force as an input to a one-dimensional thermomechanical constitutive model of a shape memory alloy wire. A design procedure, based on the analytical model, is presented for morphing fender skirts comprising radially configured smart composite elements. A half-scale fender skirt for a compact passenger car is designed, fabricated, and tested. The demonstrator has a domed unactuated shape and morphs to a flat shape when actuated using shape memory alloys. Rapid actuation is demonstrated by coupling shape memory alloys with integrated quick-release latches; the latches reduce actuation time by 95%. The demonstrator is 62% lighter than an equivalent dome-shaped steel fender skirt.

Dynamic Properties of NiTi Shape Memory Alloy and Classic Structural Materials: A Comparative Analysis

2010 ◽  
Vol 643 ◽  
pp. 37-41 ◽  
Author(s):  
Niédson José Da Silva ◽  
Estephanie Nobre Dantas Grassi ◽  
Carlos José de Araújo
Keyword(s):  
Phase Transformation ◽  
Low Temperature ◽  
Shape Memory ◽  
Smart Materials ◽  
Dynamic Properties ◽  
Functional Materials ◽  
Structural Materials ◽  
Damping Capacity ◽  
Temperature Phase ◽  
Niti Sma

Shape Memory Alloys (SMA) are smart materials that have attracted increasing attention due to their superior damping properties when compared to conventional structural materials. These functional materials exhibit high damping capacity during phase transformation as well as in the low temperature martensitic state. In this work NiTi SMA, commercial aluminum, stainless steel and brass were submitted to dynamic mechanical analysis (DMA) in a single cantilever mode. Small beam specimens were manufactured to accomplish the DMA tests. The studied NiTi presented a damping capacity peak during phase transformation, being much higher than damping of conventional materials. NiTi SMA also showed an increase of storage modulus after conversion of low temperature phase to high temperature phase while an almost linear decrease is observed for the conventional materials studied.

Shape Memory Alloy Based Actively Tuned Undamped Mass Absorber

2012 ◽  
Vol 2 (1) ◽  
pp. 66-74 ◽  
Author(s):  
M. Senthil Kumar ◽  
V. Raj Kumar ◽  
S. Shyamkirthi
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Cantilever Beam ◽  
Active Vibration Control ◽  
Design Procedure ◽  
Structural Response ◽  
Experimental Setup ◽  
Element Analysis ◽  
Labview Software ◽  
Sma Spring

An actively tuned undamped mass vibration absorber (ATVA) based on shape memory alloy (SMA) actuator is developed for attenuation of vibration in a cantilever beam. The design procedure of the ATVA is presented. The system consists of a cantilever beam mounted with shaker to generate the real-time vibration. The SMA spring with mass is attached at free end. The stiffness of SMA spring is varied dynamically in such a way to attenuate the vibration actively. Both simulation and experimentation are carried out. Simulation is carried out using Finite Element Analysis (FEA) package ANSYS software. The experiment was carried out by interfacing the experimental setup with computer along with LabVIEW software through data acquisition card (DAQ). In experimental setup, an accelerometer is used to measure the vibration which is fed to computer and in turn the SMA spring is actuated to change its stiffness which will control the vibration. The results illustrate that the developed ATVA using SMA is very effective in reducing structural response and having great potential to use as an active vibration control media.

Shape memory alloy-spring damper for seismic control and its application to bridge with laminated rubber bearings

2021 ◽  
pp. 136943322110339
Author(s):  
Sasa Cao ◽  
Jiang Yi
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Large Deformation ◽  
Design Procedure ◽  
Hysteretic Behavior ◽  
Small Displacement ◽  
Seismic Excitations ◽  
Seismic Control ◽  
Sma Spring ◽  
Rubber Bearings

This study introduces a shape memory alloy (SMA)-spring damper which is composed of SMA bars and elastic springs arranged in perpendicular. The damper depicts a curved flag-shape hysteretic behavior that is endowed with self-centering capacities and large deformation capabilities but uses reduced amount of SMA material. A design procedure is proposed to apply the SMA-spring damper to the bridge with laminated rubber bearings which would slide under seismic excitations. Analytical results validate the effectiveness of SMA-spring dampers in seismic control of the bridge: (1) The damper provides trivial stiffness to the bridge at small displacement, and the isolation efficiency of the bridge is maintained; (2) large horizontal force is provided for the structures at large deformation of the bearings, which alleviates the excessive displacement of bearings and prevents span collapse; and (3) the damper helps recenter the bearings and reduce the residual displacement of the bridge.

Effects of Annealing on Microstructure and Martensitic Transition of Ni-Mn-Co-In Ferromagnetic Shape Memory Alloys

2011 ◽  
Vol 674 ◽  
pp. 171-175
Author(s):  
Katarzyna Bałdys ◽  
Grzegorz Dercz ◽  
Łukasz Madej
Keyword(s):  
Electron Microscopy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Smart Materials ◽  
Martensitic Transition ◽  
Magnetic Shape Memory ◽  
Ferromagnetic Shape Memory Alloys ◽  
Initial State ◽  
X Ray ◽  
Ferromagnetic Shape Memory

The ferromagnetic shape memory alloys (FSMA) are relatively the brand new smart materials group. The most interesting issue connected with FSMA is magnetic shape memory, which gives a possibility to achieve relatively high strain (over 8%) caused by magnetic field. In this paper the effect of annealing on the microstructure and martensitic transition on Ni-Mn-Co-In ferromagnetic shape memory alloy has been studied. The alloy was prepared by melting of 99,98% pure Ni, 99,98% pure Mn, 99,98% pure Co, 99,99% pure In. The chemical composition, its homogeneity and the alloy microstructure were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The phase composition was also studied by X-ray analysis. The transformation course and characteristic temperatures were determined by the use of differential scanning calorimetry (DSC) and magnetic balance techniques. The results show that Tc of the annealed sample was found to decrease with increasing the annealing temperature. The Ms and Af increases with increasing annealing temperatures and showed best results in 1173K. The studied alloy exhibits a martensitic transformation from a L21 austenite to a martensite phase with a 7-layer (14M) and 5-layer (10M) modulated structure. The lattice constants of the L21 (a0) structure determined by TEM and X-ray analysis in this alloy were a0=0,4866. The TEM observation exhibit that the studied alloy in initial state has bigger accumulations of 10M and 14M structures as opposed from the annealed state.

Design Nomographs of Compression Helical Springs for Predetermined Reliability Levels

1981 ◽  
Vol 103 (2) ◽  
pp. 268-273
Author(s):  
My Dao Thien ◽  
M. Massoud
Keyword(s):  
Probabilistic Approach ◽  
Design Procedure ◽  
Axial Loading ◽  
Geometric Parameters ◽  
Computer Algorithms ◽  
Mean Values ◽  
Helical Springs ◽  
Reliability Level ◽  
Classical Design ◽  
Mission Success

This paper discusses a probabilistic approach for the design of Compression Closely Coiled Helical Springs subjected to periodic axial loading. The classical design procedure results in deterministic geometric parameters with tolerances normally chosen according to standards without due regard to their effects on the mission success as normally expressed by a reliability level. With the proposed design procedure, the engineer can specify nominal mean values for the geometric parameters and their tolerances according to a predetermined reliability level. Design nomographs are presented to help the engineer, in the early stages of design, to choose between many alternatives. Computer algorithms can easily be written to verify the final or optimum design.

scholarly journals BRINGING SYSTEMIC DESIGN IN THE EDUCATIONAL PRACTICE: THE CASE OF GENDER EQUALITY IN AN ACADEMIC CONTEXT

2021 ◽  
Vol 1 ◽  
pp. 581-590
Author(s):  
Alexis JP Jacoby ◽  
Kristel Van Ael
Keyword(s):  
Gender Inequality ◽  
Design Education ◽  
Educational Practice ◽  
Design Approach ◽  
Academic Context ◽  
Traditional Design ◽  
Systemic Problems ◽  
Societal Problems ◽  
Systemic Design

AbstractThe field of design practice and design education is reaching out to address problems that cannot be solved by introducing a single product or service. Complex societal problems such as gender inequality cannot be solved using a traditional problem-solving oriented design approach. The specific characteristics of these problems require new ways of dealing with the dynamics, scale and complexity of the problem.Systemic design is a design approach integrating systems thinking in combination with more traditional design methodologies, addressing complex and systemic problems. This paper reports a systemic design approach in an educational context for the case of academic gender inequality. We show the way the problem was addressed and how design students were invited to take a systemic perspective, provide integrated interventions and take first steps in providing instruments for implementation. We conclude with the learnings from this case study, both on the process and the results.

Stress–temperature phase diagram of a ferromagnetic Ni–Mn–Ga shape memory alloy

2005 ◽  
Vol 53 (19) ◽  
pp. 5071-5077 ◽  
Author(s):  
V.A. Chernenko ◽  
J. Pons ◽  
E. Cesari ◽  
K. Ishikawa
Keyword(s):  
Phase Diagram ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Temperature Phase ◽  
Temperature Phase Diagram
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