Showing papers on "Magneto published in 2021"

Wirelessly Actuated Thermo- and Magneto-Responsive Soft Bimorph Materials with Programmable Shape-Morphing

Abstract: Soft materials that respond to wireless external stimuli are referred to as "smart" materials due to their promising potential in real-world actuation and sensing applications in robotics, microfluidics, and bioengineering. Recent years have witnessed a burst of these stimuli-responsive materials and their preliminary applications. However, their further advancement demands more versatility, configurability, and adaptability to deliver their promised benefits. Here, a dual-stimuli-responsive soft bimorph material with three configurations that enable complex programmable 3D shape-morphing is presented. The material consists of liquid crystal elastomers (LCEs) and magnetic-responsive elastomers (MREs) via facile fabrication that orthogonally integrates their respective stimuli-responsiveness without detrimentally altering their properties. The material offers an unprecedented wide design space and abundant degree-of-freedoms (DoFs) due to the LCE's programmable director field, the MRE's programmable magnetization profile, and diverse geometric configurations. It responds to wireless stimuli of the controlled magnetic field and environmental temperature. Its dual-responsiveness allows the independent control of different DoFs for complex shape-morphing behaviors with anisotropic material properties. A diverse set of in situ reconfigurable shape-morphing and an environment-aware untethered miniature 12-legged robot capable of locomotion and self-gripping are demonstrated. Such material can provide solutions for the development of future soft robotic and other functional devices.

Wave propagation in magneto-porosity FG bi-layer nanoplates based on a novel quasi-3D refined plate theory

Abstract: A quasi-3D refined plate theory is presented with the nonlocal strain gradient theory to investigate the wave propagation in bi-layer porous FG nanoplates surrounded by an elastic medium. Both laye...

Nonlinear Oscillations of Particle-Reinforced Electro-Magneto-Viscoelastomer Actuators

Abstract: This work presents the dynamic modeling and analysis of a particle-reinforced and pre-stressed electro-magneto-viscoelastic plate actuator. The actuator belongs to a smart actuator category and is made of an electro-magneto-active polymer filled with a particular volume fraction of suitable fillers. An energy-based electro-magneto-viscoelastic model is developed to predict the actuator response and interrogate the impact of particle reinforcement on the dynamic oscillations of a pre-stressed condition of the actuator. An Euler–Lagrange equation of motion is implemented to deduce the governing dynamic equation of the actuator. The findings of the model solutions provide preliminary insights on the alteration of the nonlinear behavior of the actuator driven by DC and AC dynamic modes of actuation. It is observed that the enrichment in the particle reinforcement characterized by the amount of fillers strengthens the polymer and depleted the associated level of deformation. Also, the depletion in the intensity of oscillation and enhancement in the frequency of excitation is perceived with an increase in the particle reinforcement. In addition, the time-history response, Poincare plots, and phase diagrams are also plotted to assess the stability, periodicity, beating phenomenon, and resonant behavior of the actuator. In general, the current study provides initial steps toward the modern actuator designs for various futuristic applications in the engineering and medical field.

Features of 3D magneto-convective nonlinear radiative Williamson nanofluid flow with activation energy, multiple slips and Hall effect

Abstract: In this article, the impacts of Hall current and Arrhenius activation energy on three-dimensional hydromagnetic Williamson nanofluid flow past a slendering stretching sheet in the presence of multiple slips, viscous dissipation, Joule heating and binary chemical reaction is analyzed. The presence of nonlinear thermal radiation and nonlinear mixed convection is also taken into consideration. The dimensional governing equations are transformed into non-dimensional ordinary differential equations by using some suitable similarity transformation. The resulting coupled and highly nonlinear boundary value problem is then solved numerically by shooting technique based on Runge-Kutta-Fehlberg method. The behaviors of concentration, temperature and velocity distributions w.r.t. the various controlling parameters are illustrated graphically. However, the numerical values of local skin-friction coefficients, local heat and mass transfer rates are explained and presented in tabular form. Furthermore, a result validation is performed to check the accuracy and correctness of the obtained results by comparing the results with previously published results for some limited case of the present problem and an excellent agreement is found between the results.

Effect of Hall current in transversely isotropic magneto-thermoelastic rotating medium with fractional-order generalized heat transfer due to ramp-type heat

Abstract: This investigation is focused on the study of Hall current effect in homogeneous transversely isotropic magneto-thermoelastic (HTIMT) rotating medium with fractional-order heat transfer due to ramp-type heat. Investigation of interaction between the strain, thermal and electromagnetic fields becomes a new area of research, which is called magneto-thermoelasticity because of its effective aspects in various domains of science and technology. Laplace and Fourier transform is used for solving field equations. The expressions of temperature, stress components, displacement components, and current density components are computed in the transformed domain. The effects of Hall current, rotation and fractional-order parameter at different values in HTIMT solid are represented graphically.

Magneto-Thermal Analysis of an Axial-Flux Permanent-Magnet-Assisted Eddy-Current Brake at High-Temperature Working Conditions

Abstract: This article proposes an analytic coupled magneto-thermal analysis of an axial-flux (AF) permanent-magnet-assisted (PMA) eddy-current brake (ECB) at high-temperature working conditions. In the topology investigated, permanent magnets (PMs) are placed into stator slot openings to increase the braking torque production capability. This modification enables to control the magnet flux by altering the dc excitation current. However, the utilization of PMs will make the construction vulnerable at high operating temperatures simply because the magnet properties and the brake capability are strongly dependent on temperature. Such problems require complex coupled multiphysics finite-element analyses to obtain the actual brake performance. The proposed approach offers a simple and effective solution that consists of magnetic and thermal models, which are coupled to each other in the time domain. The nonlinear electrical, magnetic, and thermal properties are influenced by the temperature variation in time. An AF-PMA-ECB prototype is manufactured to validate the proposed coupled models and the experimental studies confirm that the proposed approach provides very practical results to determine the working conditions of the AF-PMA-ECB at high-temperature operations.

Porosity effect on the nonlinear deflection of functionally graded magneto-electro-elastic smart shells under combined loading

Abstract: This article presents a higher-order nonlinear finite element formulation to evaluate the nonlinear deformation of functionally graded magneto-electro-elastic porous (FG-MEEP) shells under the infl...

Miscellaneous optical solitons in magneto-optic waveguides associated to the influence of the cross-phase modulation in instability spectra

Abstract: By employing the traveling-wave hypothesis to the coupled nonlinear Schrödinger equation (CNLSE), the constraint relation on metamaterials parameters and the auxiliary equation have been recovered successfully. Conjecturing the values of the coefficients of the auxiliary equation, a diversity of solutions have been constructed while respecting the conditions of existence of these solutions. By choosing adequate parameters, it is obtained W-shape bright, dark, kink, anti-kink like optical solitons for the CNLSE which controls waves in magneto-optic waveguides in the presence of cross-phase modulation (XMP). To deal with the influence of the XMP to Modulation Instability (MI), the linearization technique was adopted and the continuous wave (CW) solutions were used to obtaining the dispersion relation as well as the associated MI gain spectrum. The study of the MI gain spectrum have been done in the normal and anomalous dispersive regimes associated with zero-birefringence, linear-birefringence and circular birefringence. The MI gain spectrum curves illustrating the miscellaneous of optical solitons in the magneto-optic waveguides were obtained. It is noted that these results sufficiently illustrate the dynamic of the nonlinear optic fibers through the 3D and 2D spatiotemporal plot evolutions.

Facile Manufacturing Route for Magneto-Responsive Soft Actuators

Abstract: Magnetically driven soft actuators are unique because they are fast, remote‐controlled, conformal to rigid objects, and safe to interact with humans. Despite these multiple functionalities, a broader utilization of such actuators is hindered by the high cost and equipment‐intensive nature of currently available manufacturing processes. Herein, a simple fabrication route for magneto‐responsive soft actuators is described using cost‐effective and broadly available raw materials and equipment. The method utilizes castable silicone resins that are loaded with magnetic particles and subsequently magnetized under an external magnetic field. The experimental investigation of silicone‐based composites prepared with particles of distinct chemistries, sizes, and morphologies enables the identification of the raw materials and magnetization conditions required for the process. This leads to functional soft actuators with programmable magnetic patterns that are capable of performing pick‐and‐place, lifting, catching, and moving tasks under the remote action of an external magnetic field. By removing manufacturing hurdles associated with costly raw materials and equipment, the proposed approach is expected to facilitate the design, implementation, and exploitation of the unique functionalities of magneto‐controlled soft actuators in a wider number of applications.

Enhancement of Energy-Harvesting Performance of Magneto-Mechano-Electric Generators through Optimization of the Interfacial Layer.

Abstract: Among various energy harvester paradigms, the simple cantilever-structured magneto-mechano-electric (MME) energy generator comprises a piezoelectric material laminated on a magnetostrictive metal plate and permanent magnets as proof mass, exhibiting excellent magnetic energy-harvesting performance The current challenge in using MME energy harvesters is the mechano-electric coupling at the interface between the piezoelectric material and magnetostrictive metal layer, which depends significantly on the mechanical properties of the interfacial adhesive layer In this study, the effects of four types of adhesive interfacial layers on the output power and environmental and fatigue resistances of MME harvesters are systematically investigated An optimized MME energy generator with an adhesive interfacial layer of 188 μm thickness and elastic modulus of 31 GPa achieves colossal enhancement (∼300%) with a maximum output power density of 092 mW/cm2, while a 10 Oe (=10 G = 1 mT in air; 60 Hz) magnetic field is applied In addition, the generator exhibits a robust endurance of continuous 108 fatigue cycles and excellent temperature stability in the range of -30 to 70 °C The presented MME generator, which harvests stray magnetic energy reliably, is promising as a low-cost and efficient autonomous power source for Internet of Things devices, wireless sensor networks, and so on

Solitary dynamics of longitudinal wave equation arises in magneto-electro-elastic circular rod

Abstract: This paper examines the effectiveness of an integration scheme, which called the extended modified auxiliary equation mapping method in exactly solving a well-known non-linear longitudinal wave equ...

Analytical solution for magneto-thermo-elastic responses of an annular functionally graded sandwich disk by considering internal heat generation and convective boundary condition:

Abstract: In this paper, an exact solution for stress distribution of a rotating sandwich disk subjected to magnetic, thermal fields, and convection heat transfer with the consideration of internal heat gene...

Effects of phase-lags, rotation, and temperature-dependent properties on plane waves in a magneto-microstretch thermoelastic medium

Abstract: The present article is aimed at studying the effect of rotation and temperature-dependent properties on plane waves in a homogeneous, isotropic, initially stressed magneto-microstretch thermoelasti...

A Magneto-Thermo-Static Study of a Magneto-Rheological Fluid Damper: A Finite Element Analysis

Abstract: Nowadays, the automotive industry is oriented toward the production of new generation devices, such as magnetorheological fluid (MR fluid) dampers, which have a proven simplicity of design combined with reduced maintenance. Being devices powered by steady-state electric current, MR fluid dampers develop steady-state magnetic induction fields with associated steady-state thermal stresses and a consequent constant yield stress. In this work, an asymmetric MR damper has been studied using the finite-element method (FEM). Specifically, since steady-state electric current circulates in the coil of the device, a magneto-static analysis of the device and particularly of the strip of MR fluid contained therein is performed using the FEM. Furthermore, as the device is subject to heating during operation, a thermo-static analysis was also carried out using finite elements when different external temperatures were considered. Both analyses, performed by ANSYS ToolbBox, highlighted the areas of the device most subject to magnetic stress providing useful indications on the influence of temperature both on the magnetization of the magnetic particles and on the MR fluid as a whole.

Magneto-thermoelastic wave propagation in a finitely conducting medium: A comparative study for three types of thermoelasticity I, II, and III

Abstract: The present work is concerned with the propagation of magneto-thermoelastic plane waves of assigned frequency in a homogeneous isotropic finitely conducting elastic medium permeated by a uniform ma...

Parametric study of a novel magneto-electro-aeroelastic energy harvesting system:

Abstract: This paper investigates a parametric study on a novel type of flutter-based aeroelastic harvester by utilizing magneto-electro-elastic materials, which can be used as an alternative to piezoelectri...