Simulation-based assessment of coupled frequency response of magneto-electro-elastic auxetic multifunctional structures subjected to various electromagnetic circuits

2021 ◽  
pp. 146442072110219
Author(s):  
Vinyas Mahesh ◽  
Vishwas Mahesh ◽  
Dineshkumar Harursampath ◽  
Ahmed E Abouelregal
Keyword(s):  
Electric Fields ◽  
Solid Mechanics ◽  
Natural Frequencies ◽  
Comsol Multiphysics ◽  
Simulation Based ◽  
Electric And Magnetic Fields ◽  
Auxetic Structures ◽  
Triangular Elements ◽  
Benchmark Solutions ◽  
Free Vibration Response

This article deals with the modeling of magneto-electro-elastic auxetic structures and developing a methodology in COMSOL Multiphysics® to assess the free vibration response of such structures when subjected to various electromagnetic circuit conditions. The triple energy interaction between elastic, magnetic, and electric fields are established in the COMSOL Multiphysics® using structural mechanics and electromagnetic modules. The multiphase magneto-electro-elastic material with different percentages of piezoelectric and piezomagnetic phases are used as the material. In the solid mechanics module, the piezoelectric and piezomagnetic materials were created in stress-charge and stress-magnetization forms, respectively. The electric and magnetic fields are defined in COMSOL Multiphysics® through electromagnetic equations. Further, the customized controlled meshing constituted of free tetrahedral and triangular elements is adapted to trade-off between the accuracy and the computational expenses. The eigenvalue analysis is performed to obtain the natural frequencies of the MEE re-entrant auxetic structures. Also, the efficiency of smart auxetic structures over conventional honeycomb structures is presented throughout the manuscript. In addition, the discrepancy in the natural frequencies of the structures considering coupled and uncoupled state is also illustrated. It is believed that the modeling procedure and its outcomes serve as benchmark solutions for further design and analysis of smart auxetic magneto-electro-elastic structures.

scholarly journals A Simple Gas-Kinetic Model For Dilute and Weakly Charged Plasma Micro-Jet Flows

Fluids ◽  
2021 ◽  
Vol 6 (7) ◽  
pp. 250
Author(s):  
Shiying Cai ◽  
Chunpei Cai
Keyword(s):  
Simple Model ◽  
Electric Fields ◽  
Neutral Condition ◽  
Jet Flows ◽  
Far Field ◽  
Convection Term ◽  
Number Density ◽  
Simulation Based ◽  
Analytical Formulas ◽  
Electric Field Force

This paper presents a simple model for slightly charged gas expanding into a vacuum from a planar exit. The number density, bulk velocity, temperature, and potential at the exit are given. The electric field force is assumed weaker than the convection term and is neglected in the analysis. As such, the quasi-neutral condition is naturally adopted and the potential field is computed with the Boltzmann relation. At far field, the exit degenerates as a point source, and simplified analytical formulas for flow and electric fields are obtained. The results are generic and offer insights on many existing models in the literature. They can be used to quickly approximate the flowfield and potential distributions without numerical simulations. They can also be used to initialize a simulation. Based on these results, more advanced models may be further developed.

scholarly journals Simulation of 500 MHz Electromagnetic Interference Effect on Electrical Equipment with Various RF Grids and Enclosures

2019 ◽  
Vol 1 ◽  
pp. 21-27
Author(s):  
I.F. Warsito ◽  
H. Widyaputera ◽  
E. Supriyanto ◽  
J. Pusppanathan ◽  
M. A. A. Taib ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Electromagnetic Interference ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Electrical Equipment ◽  
Protection System ◽  
Comsol Multiphysics ◽  
Gas Industry ◽  
Near Resonance ◽  
Electric And Magnetic Fields

This paper presents the modelling and simulation of a protection system for equipment in the oil and gas industry with various RF grids and enclosures against 500 MHz electromagnetic interference (EMI). COMSOL Multiphysics®Modelling software was used in this study. Electric and magnetic fields distributions were determined by using the Generalized Minimal Residual Method (GMRES) which was integrated into COMSOL Multiphysics® Modelling software. Simulation results indicated that larger RF grid size contributed to the higher electric and magnetic field on equipment. Furthermore, without RF grid, electric and magnetic fields on the equipment were increased significantly (up to 100x). The maximum electric and magnetic fields were found to be near resonance enclosure size (299 mm for 500 MHz frequency source). The results showed that the presence of the RF grid for the EMI protection system was essential.

A Four-Noded Triangular (Tr4) Element for Solid Mechanics Problems with Curved Boundaries

2019 ◽  
Vol 17 (01) ◽  
pp. 1844003 ◽  
Author(s):  
Jun Hong Yue ◽  
Guirong Liu ◽  
Ruiping Niu ◽  
Ming Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Solid Mechanics ◽  
Accurate Approximation ◽  
Shape Functions ◽  
Curved Boundaries ◽  
Triangular Elements ◽  
Complicated Geometry ◽  
Element Method ◽  
Physics Problems

Linear triangular elements with three nodes (Tr3) were the earliest, simplest and most widely used in finite element (FE) developed for solving mechanics and other physics problems. The most important advantages of the Tr3 elements are the simplicity, ease in generation, and excellent adaptation to any complicated geometry with straight boundaries. However, it cannot model well the geometries with curved boundaries, which is known as one of the major drawbacks. In this paper, a four-noded triangular (Tr4) element with one curved edge is first used to model the curved boundaries. Two types of shape functions of Tr4 elements have been presented, which can be applied to finite element method (FEM) models based on the isoparametric formulation. FE meshes can be created with mixed linear Tr3 and the proposed Tr4 (Tr3-4) elements, with Tr3 elements for interior and Tr4 elements for the curved boundaries. Compared to the pure FEM-Tr3, the FEM-Tr3-4 can significantly improve the accuracy of the solutions on the curved boundaries because of accurate approximation of the curved boundaries. Several solid mechanics problems are conducted, which validate the effectiveness of FEM models using mixed Tr3-4 meshes.

An eigenstate formulation of the magnetotelluric impedance tensor

Geophysics ◽  
1982 ◽  
Vol 47 (8) ◽  
pp. 1204-1214 ◽  
Author(s):  
Dwight E. Eggers
Keyword(s):  
Electric Fields ◽  
Degrees Of Freedom ◽  
Homogeneous Medium ◽  
Real Space ◽  
Conventional Approach ◽  
Impedance Tensor ◽  
Electric And Magnetic Fields ◽  
Coordinate Rotation ◽  
Rotation Methods ◽  
Transverse Electromagnetic

An important step in the interpretation of magnetotelluric (MT) data is the extraction of scalar parameters from the impedance tensor Z, the transfer function which relates the observed horizontal magnetic and electric fields. The conventional approach defines parameters in terms of elements of a coordinate‐rotated tensor. The rotation angle is chosen such that Z′(θ) approximates in some sense the form for a two‐dimensional (2-D) subsurface conductivity distribution, with zero elements on the diagonal. There are two major problems with this approach. (1) Apparent resistivities, defined from the off‐diagonal elements of the rotated tensor, are independent of the trace of Z. It is problematic that apparent resistivities, the parameters for which we have physical analogs and which are most heavily used in interpretation, are insensitive to the addition of an arbitrary constant on the diagonal of Z. (2) The conventional parameter set is incomplete; there are two degrees of freedom in Z which are transparent to all parameters. Through a variation of the classical eigenstate formulation of a matrix, it is shown that in general there exist two, and only two, polarization states for which the electric and magnetic fields have the same polarization at perpendicular orientations. For each eigenstate the magnetic and electric fields are related by a scalar, the eigenvalue for that state. This scalar relationship between fields is of identical form to the solution for transverse electromagnetic (TEM) waves in a homogeneous medium and thus provides a physically more satisfactory basis for defining apparent resistivity than the conventional approach using the off‐diagonal elements of the coordinate‐rotated impedance tensor. The eigenstate and coordinate‐rotation methods yield identical results in the limited cases of 1-D and 2-D subsurface conductivity distributions. The eigenstates provide the basis for new definitions of parameters as concise, closed expressions which are complete and more amenable to interpretational insight. The polarization ellipses defined by the eigenstates provide a concise display in real space of all the information contained in the impedance tensor.

A time‐domain EM system measuring the step response of the ground

Geophysics ◽  
1984 ◽  
Vol 49 (7) ◽  
pp. 1010-1026 ◽  
Author(s):  
G. F. West ◽  
J. C. Macnae ◽  
Y. Lamontagne
Keyword(s):  
Magnetic Fields ◽  
Impulse Response ◽  
Electric Fields ◽  
Time Domain ◽  
Wide Band ◽  
Step Response ◽  
System Function ◽  
Response Measurement ◽  
Resistivity Method ◽  
Electric And Magnetic Fields

A wide‐band time‐domain EM system, known as UTEM, which uses a large fixed transmitter and a moving receiver has been developed and used extensively in a variety of geologic environments. The essential characteristics that distinguish it from other systems are that its system function closely approximates a stepfunction response measurement and that it can measure both electric and magnetic fields. Measurement of step rather than impulse response simplifies interpretation of data amplitudes, and improves the detection of good conductors in the presence of poorer ones. Measurement of electric fields provides information about lateral conductivity contrasts somewhat similar to that obtained by the gradient array resistivity method.

Hall Currents and the Ejection of Prominences by Sunspots

1949 ◽  
Vol 2 (1) ◽  
pp. 39
Author(s):  
RG Giovanelli
Keyword(s):  
Magnetic Fields ◽  
Electric Fields ◽  
Magnetic Force ◽  
Large Space ◽  
Space Charges ◽  
Surrounding Atmosphere ◽  
Electric And Magnetic Fields ◽  
Order Of Magnitude ◽  
General Movement ◽  
Set Up

During the growth of sunspots induced electric fields may be expected to be set up in the surrounding atmosphere. It is shown that, because of the comparatively low conductivity perpendicular to lines of magnetic force, there are localized regions where large space charges occur, resulting in large electric fields perpendicular to the lines of magnetic force. Consequently both positive and negative charges drift in the same sense in a direction which is at right angles to the electric and magnetic fields, giving rise to a general movement of the gas. The drift velocities are difficult to estimate, but appear to be of the order of magnitude of those found in eruptive prominences.

Elastic Constants of Nematic Liquid Crystals

1972 ◽  
Vol 27 (6) ◽  
pp. 966-976 ◽  
Author(s):  
Hans Gruler ◽  
Terry J. Scheffer ◽  
Gerhard Meier
Keyword(s):  
Magnetic Fields ◽  
Electric Fields ◽  
Detailed Comparison ◽  
Theoretical Treatment ◽  
Electrical Capacitance ◽  
Normal Deformation ◽  
Electric And Magnetic Fields ◽  
The Magnetic Field ◽  
Dynamic Phenomena ◽  
Good Agreement

Abstract We present a theoretical treatment and give experimental observations of the deformation that occurs in a nematic liquid crystal when electric or magnetic fields are applied. We consider only normal deformations in the nematic material where fluid flow and other dynamic phenomena play no role. Three important sample geometries are considered in the magnetic field, and the experimentally observed deformations are in good agreement with theory. The normal deformation induced by electric fields is of interest from a device standpoint, and we give a solution for the deformation that is valid even for large dielectric anisotropics. This solution has been experimentally verified. We give a detailed comparison of the distortions produced by electric and magnetic fields and show that the deformations are of a similar form even though the field is nonuniform in the electric case. The change in birefringence and electrical capacitance as a function of distortion is discussed as a means of observing the deformation.

scholarly journals Measurement of the transient shielding effectiveness of shielding cabinets

2008 ◽  
Vol 6 ◽  
pp. 293-298 ◽  
Author(s):  
H. Herlemann ◽  
M. Koch
Keyword(s):  
Numerical Simulations ◽  
Electromagnetic Fields ◽  
High Frequency ◽  
Comsol Multiphysics ◽  
Magnetic Shielding ◽  
Shielding Effectiveness ◽  
Transient Electromagnetic ◽  
Electric And Magnetic Fields ◽  
Numerical Tools ◽  
Gtem Cell

Abstract. Recently, new definitions of shielding effectiveness (SE) for high-frequency and transient electromagnetic fields were introduced by Klinkenbusch (2005). Analytical results were shown for closed as well as for non closed cylindrical shields. In the present work, the shielding performance of different shielding cabinets is investigated by means of numerical simulations and measurements inside a fully anechoic chamber and a GTEM-cell. For the GTEM-cell-measurements, a downscaled model of the shielding cabinet is used. For the simulations, the numerical tools CONCEPT II and COMSOL MULTIPHYSICS were available. The numerical results agree well with the measurements. They can be used to interpret the behaviour of the shielding effectiveness of enclosures as function of frequency. From the measurement of the electric and magnetic fields with and without the enclosure in place, the electric and magnetic shielding effectiveness as well as the transient shielding effectiveness of the enclosure are calculated. The transient SE of four different shielding cabinets is determined and discussed.

scholarly journals Pemodelan dan Simulasi Medan Listrik pada Jaringan Distribusi 20 kV Double Feeder Konstruksi 3B

2020 ◽  
Vol 4 (3) ◽  
pp. 109-132
Author(s):  
Mohamad Ramdan Febriana Herawan ◽  
Deny Hamdani
Keyword(s):  
Numerical Methods ◽  
Electric Field ◽  
Electric Fields ◽  
Simulation Method ◽  
Average Height ◽  
Charge Simulation Method ◽  
Simulation Experiments ◽  
Surrounding Environment ◽  
Electric And Magnetic Fields ◽  
Maximum Electric Field

ABSTRAKPeralatan listrik yang bertegangan dapat menyebabkan medan listrik di sekitar peralatan listrik, mengetahui besaran nilai medan listrik menjadi hal yang penting, untuk mengetahui paparan medan listrik pada lingkungan sekitar. Metode numerik memainkan peran penting dalam perhitungan medan listrik untuk studi medan listrik yang terkait dengan aplikasi tegangan tinggi. Charge Simulation Method merupakan salah satu metode numerik yang dapat digunakan sebagai pendekatan untuk menghitung distribusi medan listrik dan medan magnet pada penghantar yang bertegangan. Paper ini membahas pemodelan medan listrik di sekitar jaringan distribusi double feeder kontruksi 3B dengan menggunakan Matlab untuk mengetahui jarak ambang batas aman pengaruh medan listrik bagi manusia. Simulasi dilakukan pada setiap fasa konduktor dengan jarak ukuran setiap fasa diatur sesuai kontruksi yang diterapkan pada PLN. Hasil penelitian menunjukan bahwa simulasi menggunakan MATLAB pada distribusi 20 kV double feeder kontruksi 3B, hasil medan listrik maksimal pada ketinggian 1 meter atau pada ketinggian rata-rata manusia, memiliki besaran 1,54 kV/meter. Besaran medan ini lebih kecil dari batas minimal standar WHO dan SNI, sehingga masih masuk batas aman.Kata kunci: medan listrik, charge simulation method, jaringan distribusi, distribusi kontruksi double feeder 3BABSTRACTElectrical equipment can cause an electric field around the equipment, knowing the value of the electric field becomes important, to determine the exposure of the electric field to the surrounding environment. Numerical methods play an important role in the computation of electric fields for the study of electric fields related to high voltage applications. Charge Simulation Method is one of the numerical methods that can be used as an approach to computate the distribution of electric and magnetic fields in a live conductor. This paper discusses the modeling of the electric field around the distribution double feeder 3B construction network using Matlab to determine the safe threshold distance of the influence of the electric field for humans. Simulation experiments are carried out on each phase of the conductor with the distance of each phase adjusted according to the applied construction to PLN. The results showed that the simulation using MATLAB on the distribution of 20 kV double feeder construction of 3B, value of the maximum electric field at an altitude of 1 meter or at an average height of humans, has a magnitude of 1.54 kV / meter. The magnitude of this field is smaller than the minimum WHO and SNI standards, so it is still safe for humans.Keywords: electric field, charge simulation method, distribution network, 3B double feeder construction distribution

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