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Precast segmental bridge construction in seismic zones
Published in Fabio Biondini, Dan M. Frangopol, Bridge Maintenance, Safety, Management, Resilience and Sustainability, 2012
Fabio Biondini, Dan M. Frangopol
On the basis of these indications, Galfenol as reported in (Zhao et al. 2007, Yoo et al. 2011) offers, in some operating conditions, more magnetization variation for a given mechanical input variation with respect to Terfenol. However, Terfenol is less influenced by the eddy current losses in a wide range of operating frequencies due to its lower permeability. So the employment of Galfenol requires more fabrication efforts, as lamination. Galfenol has also an important feature: it can work also under tensile stresses. However for structure monitoring, where the mechanical inputs are compressive stresses, Terfenol can be fairly employed. Recently the use of another magnetostrictive material (Metglas) has been proposed for energy harvesting (Wang & Yuan 2008) . The main advantage respect to the others magnetostrictive material is that it can be laminated achieving a higher harvester compactness.
Ultrasonic additive manufacturing
Published in Adedeji B. Badiru, Vhance V. Valencia, David Liu, Additive Manufacturing Handbook, 2017
Paul J. Wolcott, Marcelo J. Dapino
Due to the low temperatures involved, the UAM process is a proven method for creating unique components including smart structures, thermal management devices, parts with embedded fibers, selectively reinforced parts, and dissimilar material joints. The temperatures of the UAM process are on the order of 150°C, well below the critical temperatures of smart materials, enabling incorporation into metallic structures without degradation of their properties as in fusion-based processes [5,17]. An example build incorporating Galfenol into aluminum is shown in Figure 17.7. Galfenol, an alloy of iron and gallium, exhibits moderately high magnetostriction (magnetic field-induced strain) and magnetoelasticity, whereby the material changes its magnetization when stressed. These responses are used to design sensors and actuators with fast dynamic response, few to no moving parts, and compact operation. Galfenol withstands combined mechanical loads, tension, and shear, and it can be machined and formed using conventional means. When implemented into aluminum structures via UAM, the Galfenol element is shielded from outside factors and the resulting robust composites can be used as contact-less sensors, electrically tunable variable resonators, and solid-state actuators. Figure 17.8a and b shows model calculations for Galfenol composites, where the effect of Galfenol volume fraction on the normalized natural frequency is shown as a function of magnetic field. Figure 17.8cand dshows the test setup and performance of a Galfenol–aluminum composite under a mechanical load showing comparisons of experimental results with model simulations for the third bending mode. Testing was conducted using a mechanical shaker to induce specified vibration modes and measured with a laser vibrometer.
Influences of growth rate on microstructures and magnetostrictive properties of Fe83Ga17 directional solidification alloys
Published in Philosophical Magazine, 2021
Xuan Zhao, Xiao Tian, Zhanquan Yao, Lijuan Zhao, Rui Wang, Hongbo Hao
Magnetostrictive materials have been widely applied and deeply researched since the magnetostrictive effect was first founded by Joule in 1840s on iron [1]. Up to present, the magnetostrictive materials play an increasingly important role in modern industry applications, such as micromanipulations, torque sensing, liquidometers and ultrasonic transducers [2–5]. The first generation magnetostrictive materials, Fe, Ni and their alloys, possess superb ductility, and they can be processed into thin sheets and wires [6–8], but their magnetostrictive properties do not exceed 100 ppm. Then the Tb-Dy-Fe alloys have been found to offer giant magnetostriction of over 1000 ppm with minimum cubic anisotropy, but the cost of heavy rare earths is high [9,10]. Surprisingly, a newly type magnetostrictive materials, Fe-Ga (Galfenol) alloy was found by A.E. Clark et al. [11] and appears to be the most promising candidate for magnetostrictive materials. Compared with Tb-Dy-Fe alloys, Fe-Ga alloys possesses multiple advantages of moderate magnetostriction in low applied field and lower cost, and great mechanical forming property [12,13].
Active vibration control of carbon nanotube-reinforced composite beam submerged in fluid using magnetostrictive layers
Published in Mechanics Based Design of Structures and Machines, 2022
Mohammad Fadaee, Mostafa Talebitooti
Ternofel-D and Galfenol as magnetostrictive materials are smart and adaptive materials in which their deformations can be controlled by a magnetic field and also, they can produce a magnetic field when expose to a strain field (Deng and Dapino 2017). Due to their controllable properties, magnetostrictive materials have been implemented by many researchers and engineers to mitigate vibration of different structures (Bryant et al. 1993; Scheidler, Asnani, and Dapino 2016). During past two decades, some papers considered vibration suppression of beams (Reddy and Barbosa 2000; Kumar et al. 2003; Yas and Samadi 2012; Sheikholeslami et al. 2017; Arefi and Arani 2018) and plates (Hong 2014; Arani, Arani, and Maraghi 2015; Santapuri, Scheidler, and Dapino 2015) with magnetostrictive layers.