Straight Shape Setting of Nitinol Wires by Using a Laser Beam

2015 ◽  
Author(s):  
Carlo Alberto Biffi ◽  
Mauro Coduri ◽  
Riccardo Casati ◽  
Ausonio Tuissi
Keyword(s):  
Laser Beam ◽  
Shape Memory ◽  
High Energy ◽  
Elastic Response ◽  
X Rays ◽  
Wire Length ◽  
Laser Technology ◽  
Production Route ◽  
Thin Wires ◽  
The Wire

Shape setting is a fundamental step in the production route of Nitinol Shape Memory Alloys (SMAs) for the fixing of the functional properties, such as the shape memory effect and the pseudo-elasticity. The conventional method for making the shape setting needs the use of furnaces. In this work laser technology was adopted for performing the straight shape setting on commercially available Nitinol thin wires. The laser beam was moved along the wire length for inducing the functional performances. Calorimetric and pseudo-elastic response of the wires, laser annealed, were studied; high energy X-Rays diffraction was done for studying the evolution of the microstructure texture. It can be stated that the laser technology can realize the shape setting of thin SMA wires with pseudo-elastic properties; the wire performances can be modulated in function of the laser power.

Laser shape setting of superelastic nitinol wires: Functional properties and microstructure

2017 ◽  
Vol 10 (01) ◽  
pp. 1740008 ◽  
Author(s):  
Ausonio Tuissi ◽  
Mauro Coduri ◽  
Carlo Alberto Biffi
Keyword(s):  
Laser Beam ◽  
Shape Memory ◽  
Functional Properties ◽  
High Energy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Production Route ◽  
Thin Wires ◽  
The Wire

Shape setting is one of the most important steps in the production route of Nitinol Shape Memory Alloys (SMAs), as it can fix the functional properties, such as the shape memory effect and the superelasticity (SE). The conventional method for making the shape setting is performed at 400–500[Formula: see text]C in furnaces. In this work, a laser beam was adopted for performing straight shape setting on commercially available austenitic Nitinol thin wires. The laser beam, at different power levels, was moved along the wire length for inducing the functional performances. Calorimetric, pseudo-elastic and microstructural features of the laser annealed wires were studied through differential scanning calorimetry, tensile testing and high energy X-ray diffraction, respectively. It can be stated that the laser technology can induce SE in thin Nitinol wires: the wire performances can be modulated in function of the laser power and improved functional properties can be obtained.

scholarly journals Texture Determination of Thin Cu-Wires by Synchrotron Radiation

2005 ◽  
Vol 495-497 ◽  
pp. 131-136 ◽  
Author(s):  
Heinz Günter Brokmeier ◽  
Brigitte Weiss ◽  
Sang Bong Yi ◽  
Wenhai Ye Yi ◽  
Klaus Dieter Liss ◽  
...  
Keyword(s):  
High Energy ◽  
Beam Line ◽  
X Rays ◽  
Sample Holder ◽  
Wire Length ◽  
Energy Beam ◽  
Thin Wires ◽  
Absorption Correction ◽  
High Penetration

A new method to investigate thin wires has been tested, which is based on a special sample holder and on a high energy X-rays. Due to the high penetration power of high energy Xrays quantitative texture data will be obtained without any additional corrections such as constant volume correction and absorption correction. The measurements have been carried out at the high energy beam line BW5 at HASYLAB – DESY (Hamburg). In order to overcome grain statistics problems on the investigated Cu-wire of 122µm thickness a special scanning routine together with the sample preparation allows to average over a wire length between 1mm and up to 240 mm.

Experimental Investigation of High-Speed/High-Voltage SMA Actuation

2017 ◽  
Author(s):  
Paul Motzki ◽  
Tom Gorges ◽  
Thomas Würtz ◽  
Stefan Seelecke
Keyword(s):  
Shape Memory ◽  
High Voltage ◽  
Supply Voltage ◽  
High Energy ◽  
Wire Diameter ◽  
High Current ◽  
Sma Actuator ◽  
The Wire ◽  
Supply Voltages ◽  
A Current

The thermal shape memory effect describes the ability of a deformed material to return to its original shape when heated. This effect is found in shape memory alloys (SMAs) such as nickel-titanium (NiTi). SMA actuator wire is known for its high energy density and allows for the construction of compact systems. An additional advantage is the so-called “self-sensing” effect, which can be used for sensor tasks within an actuator-sensor-system. In most applications, a current is used to heat the SMA wires through joule heating. Usually a current between zero and four ampere is recommended by the SMA wire manufacturers depending on the wire diameter. Therefore, supply voltage is adjusted to the SMA wire’s electrical resistance to reach the recommended current. The focus of this work is to use supply voltages of magnitudes higher than the recommended supply voltages on SMA actuator wires. This actuation method has the advantage of being able to use industry standard voltage supplies for SMA actuators. Additionally, depending on the application, faster actuation and higher strokes can be achieved. The high voltage results in a high current in the SMA wire. To prevent the wire from being destroyed by the high current, short pulses in the micro- and millisecond range are used. As part of the presented work, a test setup has been constructed to examine the effects of the crucial parameters such as supply voltage amplitude, pulse duration, wire diameter and wire pre-tension. The monitored parameters in this setup are the wire displacement, wire current and force generated by the SMA wire. All sensors in this setup and their timing is validated through several experiments. Additionally, a highspeed optical camera system is used to record qualitative videos of the SMA wire’s behavior under there extreme conditions. This optical feedback is necessary to fully understand and interpret the measured force and displacement signals.

Design Framework for Multi-Section Shape Memory Alloy Axial Actuators Considering Material and Geometric Uncertainties

2020 ◽  
Author(s):  
Weilin Guan ◽  
Edwin A. Peraza Hernandez
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
High Energy ◽  
High Energy Density ◽  
Design Framework ◽  
Efficient Design ◽  
Cross Sectional ◽  
Geometric Uncertainties ◽  
In Series ◽  
The Wire

Abstract Shape memory alloys are metallic materials with the capability of performing as high energy density actuators driven by temperature control. This paper presents a design framework for shape memory alloy (SMA) axial actuators composed of multiple wire sections connected in series. The various wire sections forming the actuators can have distinct cross-sectional areas and lengths, which can be modulated to adjust the overall thermomechanical response of the actuator. The design framework aims to find the optimal cross-sectional areas and lengths of the wire sections forming the axial actuator such that its displacement vs. temperature actuation path approximates a target path. Constraints on the length-to-diameter aspect ratio and stress of the wire sections are incorporated. A reduced-order numerical model for the multi-section SMA actuators that allows for efficient design evaluations is derived and implemented. An approach to incorporate uncertainty in the geometry and material parameters of the actuators within the design framework is implemented to allow for the determination of robust actuator designs. A representative application example of the design framework is provided illustrating the benefits of using multiple wire sections in axial actuators to modulate their overall response and approximate a target displacement vs. temperature actuation path.

Synchrotron X-Ray Study of Texture in Cold-Worked Shape-Memory NiTi-Wires

2001 ◽  
Vol 678 ◽  
Author(s):  
Andreas Schuster ◽  
Heinz Voggenreiter ◽  
Dorian K. Balch ◽  
David C. Dunand
Keyword(s):  
Shape Memory ◽  
High Energy ◽  
Niti Shape Memory Alloy ◽  
X Rays ◽  
Parallel Beam ◽  
X Ray ◽  
Small Constant ◽  
Strain Change ◽  
Cold Worked ◽  
Niti Wires

AbstractA series of martensitic, near-equiatomic NiTi shape-memory alloy wires was deformed to strains ranging from 1 to 40% up to stresses of 920 MPa. After deformation, the wires were exposed to a monochromatic, parallel beam of high energy x-rays oriented perpendicular to the wire axis. The transmitted low index diffraction rings show that martensitic texture is increasing with prestrain up to ε=15% after twinning is complete. Further prestraining in the plastic range lowers the texture again indicating that twinning- and plasticity-textures cancel partially each other. Also, deformed NiTi-wires were heated and cooled from 20°C to 200°C under a small constant stress of 6 MPa. The strain change due to the Two-Way Shape-Memory Effect was measured and correlated to the diffraction results.

Modelling of Wire-on-Drum Shape Memory Actuators for Linear and Rotary Motion

2010 ◽  
Author(s):  
Giovanni Scire` Mammano ◽  
Eugenio Dragoni
Keyword(s):  
Shape Memory ◽  
Frictional Coefficient ◽  
Rolling Contact ◽  
Elastic Response ◽  
Pulse Excitation ◽  
Linear Elastic ◽  
Shape Memory Actuators ◽  
Martensitic State ◽  
The Wire ◽  
Technical Solutions

The paper presents the analytical model of a linear/rotary solid-state actuator formed by a shape memory wire wound over a cylindrical drum. The model assumes a bilinear stress-strain behaviour of the wire in the martensitic state (low temperature) and a linear elastic response in the austenitic state (high temperature). Based on simple equilibrium conditions, the model calculates the stress and strain distributions in the wire subjected to a constant backup force and to frictional sliding forces at the contact with the drum. Closed-form expressions are supplied for the stroke produced by whatever actuator geometry. The model shows that large strokes (up to one half of the drum diameter) are achieved if the frictional coefficient is kept below 0.01. Rolling-contact architectures or sonic-pulse excitation of the drum are discussed as technical solutions to obtain such low friction values.

scholarly journals WEDM single crater asymmetry

2021 ◽  
Author(s):  
Paulo M. B. Esteves ◽  
Moritz Wiessner ◽  
João V. M. R. Costa ◽  
Maria Sikora ◽  
Konrad Wegener
Keyword(s):  
Aspect Ratio ◽  
Electrical Discharge Machining ◽  
Energy Levels ◽  
High Energy ◽  
Optical Microscope ◽  
Wire Length ◽  
Machined Surface ◽  
Marquardt Algorithm ◽  
Heat Effects ◽  
The Wire

AbstractIn wire electrical discharge machining (WEDM), the erosion is made through a series of overlapped craters. The shape of these craters has a relevant impact on the characteristics of the machined surface, from surface roughness to heat effects during the spark. Current models on EDM process do not represent specific WEDM characteristics, such as radial asymmetry of the crater or geometrical effects on the crater shape. In order to characterize the crater’s dimensions in WEDM, single discharge experiments are performed on polished steel for pulses with different energy levels. A 3D optical microscope is used to map the single craters’ topographies (experimental work). To capture the craters’ dimensions, an ellipsoidal equation is applied with a Levenberg–Marquardt algorithm. The ellipsoidal equation is capable of identifying the dimensions along the wire length, perpendicular to the wire and the depth of the crater. The ratio between the dimension along the wire and the dimension perpendicular to the wire is used to define a crater’s aspect ratio and characterizes its elongation. The aspect ratio of the single craters is found to be dependent on the pulse energy. Low-energy pulses create rounder craters, while high-energy pulses form elongated craters that are longer along the wire length. Such behavior suggests that the crater formation is constricted by the wire geometry, having a preferential direction of growth, along the wire length.

In Situ Experiment for Laser Beam Welding of Ti Alloys Using High-Energy X-Rays

2017 ◽  
Vol 905 ◽  
pp. 114-119
Author(s):  
Peter Staron ◽  
Jie Liu ◽  
Stefan Riekehr ◽  
Norbert Schell ◽  
Norbert Huber ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Laser Beam ◽  
Phase Transformations ◽  
Laser Beam Welding ◽  
High Energy ◽  
X Rays ◽  
Synchrotron Source ◽  
Ti Alloys ◽  
In Situ Experiments

The laser beam welding (LBW) process has many advantages for industrial production; however, it still has to be optimized for two-phase Ti alloys. Phase transformations and residual stresses play a crucial role for welding these alloys. Specific questions about the development of phase content during fast heating with a laser and rapid cooling can only be addressed with time-resolved in-situ experiments, avoiding artefacts from quenching. Also the residual stress development during cooling depends on the occurring phase transformations. Thus, an LBW chamber employing a fibre laser was developed for use with high-energy X-rays from a synchrotron source. Bead-on-plate welding experiments with 2.5 mm thick samples were carried out at the HZG high-energy materials science beamline (HEMS) at DESY, Hamburg. The first experiments focused on the solid-solid phase transformations in a Ti-6Al-4V alloy. Moreover, residual stresses developing during cooling were studied.

The Basic Physical Principles of Ion, Electron, and X-Ray Detectors and Their Application to Microanalysis

1985 ◽  
Vol 43 ◽  
pp. 154-157
Author(s):  
A.J. Tousimis
Keyword(s):  
Ion Beam ◽  
Depth Resolution ◽  
Sample Surface ◽  
High Energy ◽  
X Rays ◽  
X Ray ◽  
Electrons And Ions ◽  
Spatial Depth ◽  
Minimum Surface Area ◽  
Physical Principles

An integral and of prime importance of any microtopography and microanalysis instrument system is its electron, x-ray and ion detector(s). The resolution and sensitivity of the electron microscope (TEM, SEM, STEM) and microanalyzers (SIMS and electron probe x-ray microanalyzers) are closely related to those of the sensing and recording devices incorporated with them.Table I lists characteristic sensitivities, minimum surface area and depth analyzed by various methods. Smaller ion, electron and x-ray beam diameters than those listed, are possible with currently available electromagnetic or electrostatic columns. Therefore, improvements in sensitivity and spatial/depth resolution of microanalysis will follow that of the detectors. In most of these methods, the sample surface is subjected to a stationary, line or raster scanning photon, electron or ion beam. The resultant radiation: photons (low energy) or high energy (x-rays), electrons and ions are detected and analyzed.

Development of Wire Suspended Robot System (ARANEUS 2.0) for Bridge Inspection

10.29007/zw9k ◽  
2020 ◽  
Author(s):  
Kazuhide Nakata ◽  
Kazuki Umemoto ◽  
Kenji Kaneko ◽  
Ryusuke Fujisawa
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Concrete Surface ◽  
Wire Length ◽  
High Definition ◽  
Bridge Inspection ◽  
Robot System ◽  
Inspection Method ◽  
Aerial Vehicle ◽  
The Wire

This study addresses the development of a robot for inspection of old bridges. By suspending the robot with a wire and controlling the wire length, the movement of the robot is realized. The robot mounts a high-definition camera and aims to detect cracks on the concrete surface of the bridge using this camera. An inspection method using an unmanned aerial vehicle (UAV) has been proposed. Compared to the method using an unmanned aerial vehicle, the wire suspended robot system has the advantage of insensitivity to wind and ability to carry heavy equipments, this makes it possible to install a high-definition camera and a cleaning function to find cracks that are difficult to detect due to dirt.

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