Manufacture and Electro-Thermomechanical Characterization of a SMA Copper-Based Cylindrical Connector

2010 ◽  
Vol 643 ◽  
pp. 29-35 ◽  
Author(s):  
Niédson José Da Silva ◽  
Jobson Alberto Silva ◽  
Rômulo Pierre Batista Dos Reis ◽  
Jackson de Brito Simões ◽  
Carlos José de Araújo
Keyword(s):  
Shape Memory ◽  
Thermal Activation ◽  
Functional Materials ◽  
Thermomechanical Properties ◽  
Contact Forces ◽  
Normal Contact ◽  
Electrical Connector ◽  
Electrical Connections ◽  
Cylindrical Element

The relevant and unique thermomechanical properties of shape memory alloys (SMA) have motivated researches for applications in several fields of engineering. The pseudoelasticity and shape memory effect (SME) are some behaviors displayed by these functional materials. The aim of the current work is the manufacture, physical characterization and investigation of electro-thermomechanical response of a SMA copper-based cylindrical element aiming the development of a smart electrical connector. The cylindrical element was manufactured by plasma melting and injection molding of a CuAlNi based SMA. During thermal activation, the SMA cylindrical element presented satisfactory movement of closure through the recovery of its shape, demonstrating a strong potential to generate normal contact forces useful for electrical connections.

Functional Characterization of NiTi Shape Memory Elements for Smart Micro-Actuation

2013 ◽  
Author(s):  
Carlo Alberto Biffi ◽  
Luca Bonacina ◽  
Adelaide Nespoli ◽  
Barbara Previtali ◽  
Ausonio Tuissi
Keyword(s):  
Shape Memory ◽  
Mechanical Response ◽  
Thermal Hysteresis ◽  
Functional Characterization ◽  
Functional Materials ◽  
Mechanical Tests ◽  
Calorimetric Analysis ◽  
Production Route ◽  
Definition Of

Shape Memory Alloys (SMAs) are smart and functional materials, which are considered good candidates for the activation of devices for the automotive, aerospace, biomedical and mechanical systems, thanks to the shape memory effect. In this work, a study on the mechanical response of NiTi SMA snake like elements has been proposed. The production route of these elements from thin sheets, was given by laser machining followed by chemical etching. The micro-elements were characterized by means of calorimetric analysis for the definition of the theoretical operating temperatures and by means of thermo-mechanical testing for the evaluation of their functional performances. Mechanical tests has been carried out to assess the tensile behavior of martensite and austenite separately, and to evaluate the thermal hysteresis under different constant loads. Moreover, Finite Element Modeling (FEM) has been also accomplished to study the numerical evaluation of the stress field that origins by the application of the different loads in both the martensitic and austenitic phases.

scholarly journals Microstructure and Thermomechanical Characterization of Fe-28Mn-6Si-5Cr Shape Memory Alloy

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 649
Author(s):  
Antonio Collazo ◽  
Raúl Figueroa ◽  
Carmen Mariño-Martínez ◽  
Carmen Pérez
Keyword(s):  
Shape Memory ◽  
Thermal Activation ◽  
Tensile Tests ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Potential Applications ◽  
Ε Martensite ◽  
Microscopy Techniques ◽  
Activation Cycle

Iron-based shape memory alloys (SMAs) have been widely studied during the last years, producing new formulations with potential applications in civil engineering. In the present paper, the microstructure and the thermomechanical behavior of the Fe-28Mn-6Si-5Cr memory alloy has been investigated. At room temperature, the presence of ε-martensite and γ-austenite was confirmed using optical and electron microscopy techniques. The martensitic transformation temperatures (As, Af, Ms, and Mf) were determined by differential scanning calorimetry, together with an X-ray diffraction technique. The use of these techniques also confirmed that this transformation is not totally reversible, depending on the strain degree and the number of thermal cycles. From the kinetics study of the ε → γ transformation, the isoconversion curves (transformation degree versus time) were built, which provided the information required to optimize the thermal activation cycle. Tensile tests were performed to characterize the mechanical properties of the studied alloy. These kinds of tests were also performed to assess the shape memory effect, getting a recovery stress of 140 MPa, after a 7.6% pre-strain and a thermal activation up to 160 °C.

scholarly journals Twin-Wire Networks for Zero Interconnect, High-Density 4-Wire Electrical Characterizations of Materials

Research ◽  
2022 ◽  
Vol 2022 ◽  
pp. 1-10
Author(s):  
Nerio Andrés Montoya ◽  
Valeria Criscuolo ◽  
Andrea Lo Presti ◽  
Raffaele Vecchione ◽  
Christian Falconi
Keyword(s):  
Statistical Significance ◽  
Standard Technique ◽  
High Density ◽  
Contact Forces ◽  
3D Printed ◽  
Lord Kelvin ◽  
Electrical Connections ◽  
Nanoparticle Ink ◽  
Electrical Characterizations

Four-wire measurements have been introduced by Lord Kelvin in 1861 and have since become the standard technique for characterizing small resistances and impedances. However, high-density 4-wire measurements are generally complex, time-consuming, and inefficient because of constraints on interconnects, pads, external wires, and mechanical contacts, thus reducing reproducibility, statistical significance, and throughput. Here, we introduce, systematically design, analyze, and experimentally validate zero interconnect networks interfaced to external instrumentation by couples of twin wire. 3D-printed holders with magnets, interconnects, nonadhesive layers, and spacers can effortlessly establish excellent electrical connections with tunable or minimum contact forces and enable accurate measurements even for delicate devices, such as thin metals on soft polymers. As an example, we measured all the resistances of a twin-wire 29-resistor network made of silver-nanoparticle ink printed on polyimide, paper, or photo paper, including during sintering or temperature calibration, resulting in an unprecedentedly easy and accurate characterization of both resistivity and its temperature coefficient. The theoretical framework and experimental strategies reported here represent a breakthrough toward zero interconnect, simple, and efficient high-density 4-wire characterizations, can be generalized to other 4-wire measurements (impedances, sensors) and can open the way to more statistically meaningful and reproducible analyses of materials, high-throughput measurements, and minimally invasive characterizations of biomaterials.

TESTING DEVICE FOR CHARACTERIZATION OF THE THERMOMECHANICAL PROPERTIES OF A SHAPE MEMORY ALLOY ACTUATOR

2015 ◽  
Author(s):  
David Domingos Soares da Silva ◽  
Ewerton Freitas de Medeiros ◽  
Lipson Douglas de Oliveira Silva ◽  
Melquisedeque Shaloon Bento da Silva Gomes ◽  
Alysson Domingos Silvestre ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Thermomechanical Properties ◽  
Testing Device ◽  
Shape Memory Alloy Actuator

scholarly journals Investigation of Mechanical Properties of Large Shape Memory Alloy Bars under Different Heat Treatments

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3729 ◽  
Author(s):  
Liping Kang ◽  
Hui Qian ◽  
Yuancheng Guo ◽  
Chenyang Ye ◽  
Zongao Li
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Shape Memory ◽  
Earthquake Engineering ◽  
Damping Ratio ◽  
Treatment Strategies ◽  
Functional Materials ◽  
Tensile Tests ◽  
Thermomechanical Properties ◽  
Different Diameters

Shape memory alloys (SMAs) are a class of functional materials that possess unique thermomechanical properties, such as shape memory effect (SME), superelasticity (SE), damping, and good fatigue and corrosion resistance, which enable them to become ideal materials for applications in earthquake engineering. Numerous studies have shown that the mechanical properties of superelastic SMAs mainly depend on the wire form, or the relationship between the microstructure and thermally induced phase transitions. However, extremely few studies have elucidated the effects of the heat-treatment strategy, size effect of large diameters, and cyclic loading. Herein, the mechanical properties of SMA bars, such as residual strain, energy dissipation, and equivalent damping ratio, were studied with different heat-treatment strategies, cyclic loadings, and strain amplitudes; this was achieved by conducting cyclic tensile tests on SMA bars with four different diameters. The results indicate that the maximum phase transformation stress was obtained with a 14 mm SMA bar subjected to heat treatment at 400 ℃ for 15 min. The mechanical properties were relatively stable after five loading–unloading cycles, which should be considered in engineering applications. The test results provide a mechanical basis for using large SMA bars in self-centering structures in seismic regions.

scholarly journals Fabrication of Thermal Plasma Sprayed NiTi Coatings Possessing Functional Properties

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 610
Author(s):  
Sneha Samal ◽  
Ondřej Tyc ◽  
Jan Cizek ◽  
Jakub Klecka ◽  
František Lukáč ◽  
...  
Keyword(s):  
Shape Memory ◽  
Inductively Coupled Plasma ◽  
Thermomechanical Properties ◽  
Niti Shape Memory Alloy ◽  
Chemical Homogeneity ◽  
Aisi 304 ◽  
Inductively Coupled ◽  
Plasma Sprayed ◽  
Thick Coatings

Thick NiTi shape memory alloy coatings (300–500 µm) were produced on graphite and AISI 304 substrates by radio frequency inductively-coupled plasma spray technology (RF-ICP) from feedstock NiTi powders. Their microstructure as well as chemical and phase composition were characterized and a methodology for the characterization of functional shape memory properties of the thick coatings was developed. The coatings exhibited cubic to monoclinic martensitic transformation and shape memory effect. The presented results prove that NiTi coatings with functional thermomechanical properties can be easily produced on structural materials by RF-ICP. Further optimization will be needed to prepare NiTi coatings with better microstructural and chemical homogeneity.

Investigate of Electrical Conductivity of Shape-Memory Polymer Filled with Carbon Black

2008 ◽  
Vol 47-50 ◽  
pp. 714-717 ◽  
Author(s):  
Xin Lan ◽  
Jin Song Leng ◽  
Yan Ju Liu ◽  
Shan Yi Du
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Shape Memory ◽  
Shape Recovery ◽  
Volume Fraction ◽  
Shape Memory Polymer ◽  
Recovery Process ◽  
Thermomechanical Properties ◽  
Electrically Conductive ◽  
New System

A new system of thermoset styrene-based shape-memory polymer (SMP) filled with carbon black (CB) is investigated. To realize the electroactive stimuli of SMP, the electrical conductivity of SMP filled with various amounts of CB is characterized. The percolation threshold of electrically conductive SMP filled with CB is about 3% (volume fraction of CB), which is much lower than many other electrically conductive polymers. When applying a voltage of 30V, the shape recovery process of SMP/CB(10 vol%) can be realized in about 100s. In addition, the thermomechanical properties are also characterized by differential scanning calorimetery (DSC).

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