Publications related to Nickel titanium

EBSD study of variant reorientation, texture, and twin formation in a martensitic NiTi alloy deformed in compression

Cyril Cayron, Roland Logé, Mathijs Pieter van der Meer, Junfeng Xiao

Martensitic crystallography plays a vital role in the texture evolution and mechanical properties in Nickel-Titanium (NiTi) shape memory alloys when subjected to deformation. However, their microstructural changes during deformation are not well known and ...

Pergamon-Elsevier Science Ltd2023

Zero Parasitic Shift Pivoting Kinematic Structures Based On Coupled N-RRR Planar Parallel Mechanisms For Flexure Pivot Design

Simon Nessim Henein, Florent Cosandier, Loïc Benoît Tissot-Daguette, Etienne Frédéric Gabriel Thalmann

Flexure pivots, which are widely used for precision mechanisms, generally have the drawback of presenting parasitic shifts accompanying their rotation. The known solutions for canceling these undesirable parasitic translations usually induce a loss in radi ...

ASME Amer Soc Mechanical Engineers2023

Fabrication and Characterization of the Kirigami-Inspired SMA-Powered Actuator

Yves Perriard, Thomas Guillaume Martinez, Marjan Ghorbani, Sean Thomas, Guilain Lionel Germain Lang

This paper presents an innovative approach to creating Shape Memory Alloys (SMA)-based actuators that are lightweight, compact, and capable of providing large strokes. Inspired by the Kirigami structure, an SMA actuator is designed using the Ω -pattern, wh ...

2023

The General Crack Component Model for reversed cyclic shear

David Michael Volpe Ruggiero

A growing body of research has shown that reversed cyclic shear loading of reinforced concrete (RC) causes effects that are not accounted for in monotonic behavioral models. Notable among these effects are a reduction in shear strength and significant plas ...

2023

Origin of the enhanced pseudo-elasticity of additively manufactured Fe-17Mn-5Si-4Ni-10Cr-(V, C) shape memory alloy fabricated by laser powder bed fusion

Christian Leinenbach, Irene Ferretto

This study investigated the origin of the enhanced pseudo-elasticity of additively manufactured vanadium carbide-containing Fe-based shape memory alloys. The aged samples with two different starting microstructures, as-built and solution-treated, showed co ...

Elsevier Science Sa2023

Laser powder bed fusion of Fe-based shape memory alloys for novel structural metamaterials and "smart" structures

Irene Ferretto

Laser powder bed fusion (LPBF) is a powder-based additive manufacturing (AM) technique, which shows great potential in the production of complex-shaped parts with unprecedented design freedom. In addition, it allows for an active manipulation of the micros ...

EPFL2023

Non-Linear Behaviors In The Dynamics Of Complex Systems Through A Multifractal Hydrodynamic Model

Maria-Alexandra Paun

Some non-linear behaviors in the dynamics of complex systems using the Scale Relativity Theory in the form of Multifractal Hydrodynamic Model are analyzed. By assimilating any complex system to a mathematical multifractal-type object, it is shown that the ...

UNIV POLITEHNICA BUCHAREST, SCI BULL2022

Synthesis of Novel Integrated Actuators Powered by Shape Memory Alloys

Sean Thomas

In the modern age of miniaturisation, Smart Materials, a type of material that reacts mechanically to a certain stimulus, have become an integral part of this revolution. Among these materials, Shape Memory Alloys (SMAs), which have the highest volumetric ...

EPFL2022

Control-Free Mechanical Oscillator Powered by Shape Memory Alloys

Yves Perriard, Paolo Germano, Thomas Guillaume Martinez, Sean Thomas

Shape Memory Alloy (SMA) based actuators have been commonly used in applications that require being compact and lightweight. In this paper, the inherent stiffness of a flexure-based linear guide is used to create a bias-spring SMA actuator which further re ...

IEEE2021

Microstructural Evolution Study of Fe-Mn-Al-C Steels Through Variable Thermomechanical Treatments

Roland Logé, Oscar Zambrano Zambrano

The microstructural evolution of the two austenitic alloys Fe-20Mn-3Al-0.7C wt pct and Fe-20Mn-6Al-0.7C wt pct when different thermal and thermomechanical treatments are performed has been studied. To this end, a generic industrial die of 100 ton capacity ...

SPRINGER2021

Designing compliant mechanisms composed of shape memory alloy and actuated by induction heating

Yves Perriard, Paolo Germano, Thomas Guillaume Martinez, Adrien Jean-Michel Thabuis, Sean Thomas

Shape Memory Alloys (SMAs) are a type of smart materials that reacts mechanically to heat. Due to their complex behavior, they are often used in a simple geometry such as wires. This constrains the output displacement of the alloy to a simple linear contra ...

2021

Experimental behavior of iron-based shape memory alloys under cyclic loading histories

Dimitrios Lignos, Albano António De Abreu E Presa De Castro E Sousa, Diego Isidoro Heredia Rosa, Masoud Motavalli, Alexander Riley Hartloper, Elyas Ghafoori

The present paper investigates the behavior of iron-based shape memory alloys (Fe-SMAs) subjected to cyclic inelastic straining by means of uniaxial coupon experiments. The tests feature round bar coupons subjected to a broad range of uniaxial cyclic strai ...

2021

A 4D printed active compliant hinge for potential space applications using shape memory alloys and polymers

Jamie Paik, Zhenishbek Zhakypov, Jian-Lin Huang, Ralph Spolenak

This paper presents the proof-of-concept for a 4D printed active compliant hinge with a selectively variable stiffness for the deployment and reorientation of satellite appendages. We use 4D printing to create an active compliant hinge capable of bending t ...

IOP PUBLISHING LTD2021

An untethered mechanically-intelligent inchworm robot powered by a shape memory alloy oscillator

Yves Perriard, Paolo Germano, Thomas Guillaume Martinez, Sean Thomas

Shape Memory Alloy (SMA) based actuators have become ideal candidates for use in compact and lightweight applications. These smart materials have often been referred to as artificial muscles due to their high work volume density. In this paper, a flexure-b ...

2021

Influence of electric field, temperature, humidity, elastomer material, and encapsulation on the lifetime of dielectric elastomer actuators (DEAs) under DC actuation

Herbert Shea, Fabio Beco Albuquerque

We present the effect of electric field, temperature, humidity, type of elastomer material, and encapsulation on the lifetime of silicone-based dielectric elastomer actuators (DEAs) under DC electric fields. DEAs are promising soft actuators, but little ha ...

IOP Publishing Ltd2021

What EBSD and TKD Tell Us about the Crystallography of the Martensitic B2-B19′ Transformation in NiTi Shape Memory Alloys

Cyril Cayron

The complex and intricate microstructure of B19′ martensite in shape memory nickel titanium alloys is generally explained with the Phenomenological Theory of Martensitic Crystallography (PTMC). Over the last decade, we have developed an alternative approac ...

2020

Shape Memory Effect of Benchmark Compliant Mechanisms Designed With Topology Optimization

Yves Perriard, Thomas Guillaume Martinez, Adrien Jean-Michel Thabuis, Sean Thomas

Shape Memory Alloys (SMA) are a class of Smart Materials that are ideal for creating compact actuators. The complex nature of their behavior results in the use of these materials in simple geometries (wires, sheets) limiting their performances. A design me ...

IEEE2020

Multi-Output Compliant Shape Memory Alloy Bias-Spring Actuators

Yves Perriard, Thomas Guillaume Martinez, Adrien Jean-Michel Thabuis, Sean Thomas

Smart Materials such as Shape Memory Alloys (SMA) play a major role in creating Smart Actuators that are compact and high performing. Traditional SMA bias-spring actuators are only capable of a single linear output. Using topology optimization, compliant S ...

IEEE2020

Deformation mechanisms in a superelastic NiTi alloy: An in-situ high resolution digital image correlation study

Helena Van Swygenhoven, Efthymios Polatidis

An in-situ high resolution digital image correlation investigation during uniaxial tensile deformation reveals the recoverable and the non-recoverable strain mechanisms in a Ni51Ti49 alloy with a mean grain size of 35 mu m. Recoverable strain is due to the ...

2020

Deformation and degradation of superelastic NiTi under multiaxial loading

Helena Van Swygenhoven, Steven Van Petegem, Wei-Neng Hsu, Nicola Casati, Efthymios Polatidis

The degradation of the superelastic properties of a commercial NiTi alloy is studied during uniaxial, biaxial and load-path-change cycling performed in-situ with synchrotron X-ray diffraction. Careful examination of the diffraction pattern during uniaxial ...

2019