Nowadays, materials to protect equipment from unwanted multispectral electromagnetic waves are needed in a broad range of applications including electronics, medical, military and aerospace. However, the shielding materials currently in use are bulky and work effectively only in a limited frequency range. Therefore, nanostructured materials are under investigation by the relevant scientific community. In this framework, the design of multispectral shielding nanomaterials must be supplemented with proper numerical models that allow dealing with non-linearities and being effective in predicting their absorption spectra. In this study, the electromagnetic response of metal-oxide nanocrystals with multispectral electromagnetic shielding capability has been investigated. A numerical framework was developed to predict energy bands and electron density profiles of a core-shell nanocrystal and to evaluate its optical response at different wavelengths. To this aim, a finite element method software is used to solve a non-linear Poisson's equation. The numerical simulations allowed to model the optical response of $mathbf {ITO}$ - $mathbf {In_{2}O_{3}}$ core-shell nanocrystals and can be effectively applied to different nanotopologies to support an enhanced design of nanomaterials with multispectral shielding capabilities.
{"title":"Numerical Study of the Optical Response of $text{ITO}$-${text{In}_{{2}}{text O}_{{3}}}$ Core-Shell Nanocrystals for Multispectral Electromagnetic Shielding","authors":"Nicola Curreli;Matteo Bruno Lodi;Michele Ghini;Nicolò Petrini;Andrea Buono;Maurizio Migliaccio;Alessandro Fanti;Ilka Kriegel;Giuseppe Mazzarella","doi":"10.1109/JMMCT.2023.3235750","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3235750","url":null,"abstract":"Nowadays, materials to protect equipment from unwanted multispectral electromagnetic waves are needed in a broad range of applications including electronics, medical, military and aerospace. However, the shielding materials currently in use are bulky and work effectively only in a limited frequency range. Therefore, nanostructured materials are under investigation by the relevant scientific community. In this framework, the design of multispectral shielding nanomaterials must be supplemented with proper numerical models that allow dealing with non-linearities and being effective in predicting their absorption spectra. In this study, the electromagnetic response of metal-oxide nanocrystals with multispectral electromagnetic shielding capability has been investigated. A numerical framework was developed to predict energy bands and electron density profiles of a core-shell nanocrystal and to evaluate its optical response at different wavelengths. To this aim, a finite element method software is used to solve a non-linear Poisson's equation. The numerical simulations allowed to model the optical response of \u0000<inline-formula><tex-math>$mathbf {ITO}$</tex-math></inline-formula>\u0000-\u0000<inline-formula><tex-math>$mathbf {In_{2}O_{3}}$</tex-math></inline-formula>\u0000 core-shell nanocrystals and can be effectively applied to different nanotopologies to support an enhanced design of nanomaterials with multispectral shielding capabilities.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":"8 ","pages":"60-70"},"PeriodicalIF":2.3,"publicationDate":"2023-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/7274859/10003074/10013664.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-03DOI: 10.1109/JMMCT.2022.3233944
Dinshaw S. Balsara;Costas D. Sarris
There is a great need to solve CED problems on adaptive meshes; referred to here as AMR-CED. The problem was deemed to be susceptible to “long-term instability” and parameterized methods have been used to control the instability. In this paper, we present a new class of AMR-CED methods that are free of this instability because they are based on a more careful understanding of the constraints in Maxwell's equations and their preservation on a single control volume. The important building blocks of these new methods are: 1) Timestep sub-cycling of finer child meshes relative to parent meshes. 2) Restriction of fine mesh facial data to coarser meshes when the two meshes are synchronized in time. 3) Divergence constraint-preserving prolongation of the coarse mesh solution to newly built fine meshes or to the ghost zones of pre-existing fine meshes. 4) Electric and magnetic field intensity-correction strategy at fine-coarse interfaces. Using examples, we show that the resulting AMR-CED algorithm is free of “long-term instability”. Unlike previous methods, there are no adjustable parameters. The method is inherently stable because a strict algorithmic consistency is applied at all levels in the AMR mesh hierarchy. We also show that the method preserves order of accuracy, so that high order methods for AMR-CED are indeed possible.
{"title":"A Systematic Approach to Adaptive Mesh Refinement for Computational Electrodynamics","authors":"Dinshaw S. Balsara;Costas D. Sarris","doi":"10.1109/JMMCT.2022.3233944","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3233944","url":null,"abstract":"There is a great need to solve CED problems on adaptive meshes; referred to here as AMR-CED. The problem was deemed to be susceptible to “long-term instability” and parameterized methods have been used to control the instability. In this paper, we present a new class of AMR-CED methods that are free of this instability because they are based on a more careful understanding of the constraints in Maxwell's equations and their preservation on a single control volume. The important building blocks of these new methods are: 1) Timestep sub-cycling of finer child meshes relative to parent meshes. 2) Restriction of fine mesh facial data to coarser meshes when the two meshes are synchronized in time. 3) Divergence constraint-preserving prolongation of the coarse mesh solution to newly built fine meshes or to the ghost zones of pre-existing fine meshes. 4) Electric and magnetic field intensity-correction strategy at fine-coarse interfaces. Using examples, we show that the resulting AMR-CED algorithm is free of “long-term instability”. Unlike previous methods, there are no adjustable parameters. The method is inherently stable because a strict algorithmic consistency is applied at all levels in the AMR mesh hierarchy. We also show that the method preserves order of accuracy, so that high order methods for AMR-CED are indeed possible.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":"8 ","pages":"82-96"},"PeriodicalIF":2.3,"publicationDate":"2023-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49981637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1109/JMMCT.2024.3355900
{"title":"2023 Index IEEE Journal on Multiscale and Multiphysics Computational Techniques Vol. 8","authors":"","doi":"10.1109/JMMCT.2024.3355900","DOIUrl":"https://doi.org/10.1109/JMMCT.2024.3355900","url":null,"abstract":"","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":"8 ","pages":"382-391"},"PeriodicalIF":2.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10405364","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139494253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1109/JMMCT.2023.3346472
Costas Sarris
In July 2023, the IEEE Journal on Multiphysics and Multiscale Computational Techniques (J-MMCT) reached an important milestone, obtaining its first Impact Factor (2.3). The Impact Factor confirmed the position of the Journal as one of the leading publications dedicated to the latest advances in computational electromagnetics with an emphasis on methods for multiscale and multiphysics problems. This is the result of hard work and consistent efforts of everyone involved with J-MMCT, from founding Editor-in-Chief Prof. Qing-Huo Liu to all Editorial Board and Steering Committee members to date.
{"title":"Editorial The Year of the Impact Factor","authors":"Costas Sarris","doi":"10.1109/JMMCT.2023.3346472","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3346472","url":null,"abstract":"In July 2023, the \u0000<sc>IEEE Journal on Multiphysics and Multiscale Computational Techniques</small>\u0000 (J-MMCT) reached an important milestone, obtaining its first Impact Factor (2.3). The Impact Factor confirmed the position of the Journal as one of the leading publications dedicated to the latest advances in computational electromagnetics with an emphasis on methods for multiscale and multiphysics problems. This is the result of hard work and consistent efforts of everyone involved with J-MMCT, from founding Editor-in-Chief Prof. Qing-Huo Liu to all Editorial Board and Steering Committee members to date.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":"8 ","pages":"iii-iv"},"PeriodicalIF":2.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10399976","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139473656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-20DOI: 10.1109/JMMCT.2022.3230732
Boyuan Zhang;Dong-Yeop Na;Dan Jiao;Weng Cho Chew
An efficient numerical solver for the A - $Phi$ formulation in electromagnetics based on discrete exterior calculus (DEC) is proposed in this paper. The A - $Phi$ formulation is immune to low-frequency breakdown and ideal for broadband and multi-scale analysis. The generalized Lorenz gauge is used in this paper, which decouples the A equation and the $Phi$ equation. The A - $Phi$ formulation is discretized by using the DEC, which is the discretized version of exterior calculus in differential geometry. In general, DEC can be viewed as a generalized version of the finite difference method, where Stokes' theorem and Gauss's theorem are naturally preserved. Furthermore, compared with finite difference method, where rectangular grids are applied, DEC can be implemented with unstructured mesh schemes, such as tetrahedral meshes. Thus, the proposed DEC A - $Phi$ solver is inherently stable, free of spurious solutions and can capture highly complex structures efficiently. In this paper, the background knowledge about the A - $Phi$ formulation and DEC is introduced, as well as technical details in implementing the DEC A - $Phi$ solver with different boundary conditions. Numerical examples are provided for validation purposes as well.
{"title":"An A-$Phi$ Formulation Solver in Electromagnetics Based on Discrete Exterior Calculus","authors":"Boyuan Zhang;Dong-Yeop Na;Dan Jiao;Weng Cho Chew","doi":"10.1109/JMMCT.2022.3230732","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3230732","url":null,"abstract":"An efficient numerical solver for the \u0000<bold>A</b>\u0000-\u0000<inline-formula><tex-math>$Phi$</tex-math></inline-formula>\u0000 formulation in electromagnetics based on discrete exterior calculus (DEC) is proposed in this paper. The \u0000<bold>A</b>\u0000-\u0000<inline-formula><tex-math>$Phi$</tex-math></inline-formula>\u0000 formulation is immune to low-frequency breakdown and ideal for broadband and multi-scale analysis. The generalized Lorenz gauge is used in this paper, which decouples the \u0000<bold>A</b>\u0000 equation and the \u0000<inline-formula><tex-math>$Phi$</tex-math></inline-formula>\u0000 equation. The \u0000<bold>A</b>\u0000-\u0000<inline-formula><tex-math>$Phi$</tex-math></inline-formula>\u0000 formulation is discretized by using the DEC, which is the discretized version of exterior calculus in differential geometry. In general, DEC can be viewed as a generalized version of the finite difference method, where Stokes' theorem and Gauss's theorem are naturally preserved. Furthermore, compared with finite difference method, where rectangular grids are applied, DEC can be implemented with unstructured mesh schemes, such as tetrahedral meshes. Thus, the proposed DEC \u0000<bold>A</b>\u0000-\u0000<inline-formula><tex-math>$Phi$</tex-math></inline-formula>\u0000 solver is inherently stable, free of spurious solutions and can capture highly complex structures efficiently. In this paper, the background knowledge about the \u0000<bold>A</b>\u0000-\u0000<inline-formula><tex-math>$Phi$</tex-math></inline-formula>\u0000 formulation and DEC is introduced, as well as technical details in implementing the DEC \u0000<bold>A</b>\u0000-\u0000<inline-formula><tex-math>$Phi$</tex-math></inline-formula>\u0000 solver with different boundary conditions. Numerical examples are provided for validation purposes as well.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":"8 ","pages":"11-21"},"PeriodicalIF":2.3,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-20DOI: 10.1109/JMMCT.2022.3230664
Christopher K. Pratt;John C. Young;Robert J. Adams;Stephen D. Gedney
This article presents a boundary integral equation formulation for the prediction of electrostatic fields, potentials, and currents in regions comprising piecewise-homogeneous electrolytes. The integral equation is formulated in terms of the boundary electric potentials and normal electric current densities and is discretized using the locally corrected Nyström method. The method is validated by comparison to analytic solution data for both linear and nonlinear canonical problems. Solution convergence is investigated with respect to mesh discretization and basis order.
{"title":"Boundary Integral Equation Method for Electrostatic Field Prediction in Piecewise-Homogeneous Electrolytes","authors":"Christopher K. Pratt;John C. Young;Robert J. Adams;Stephen D. Gedney","doi":"10.1109/JMMCT.2022.3230664","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3230664","url":null,"abstract":"This article presents a boundary integral equation formulation for the prediction of electrostatic fields, potentials, and currents in regions comprising piecewise-homogeneous electrolytes. The integral equation is formulated in terms of the boundary electric potentials and normal electric current densities and is discretized using the locally corrected Nyström method. The method is validated by comparison to analytic solution data for both linear and nonlinear canonical problems. Solution convergence is investigated with respect to mesh discretization and basis order.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":"8 ","pages":"22-30"},"PeriodicalIF":2.3,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-16DOI: 10.1109/JMMCT.2022.3229963
Hongliang Li;Philip T. Krein;Jian-Ming Jin
A nonlinear electromagnetic (EM)-thermal coupled solver is developed for modeling ferromagnetic materials widely used in electric motors. To accurately predict machine performance, the time-domain finite element method is employed to solve this multiphysics problem. By adopting the nonlinear B-H models to account for hysteresis effects, magnetic core losses are computed as the major sources of power dissipation for magnetic materials. The resulting temperature change is then obtained and its effect on the magnetic properties is subsequently evaluated. Due to different time scales of EM field variations and heat transfer processes, different time step sizes are adopted to enhance the simulation speed. During thermal time marching, the EM solver is invoked adaptively based on material property changes, and EM losses are calculated and updated through extrapolation, resulting in an efficient EM-thermal coupling scheme. Numerical examples are presented to validate the accuracy and capabilities of the proposed EM-thermal co-simulation framework.
{"title":"Electromagnetic-Thermal Modeling of Nonlinear Magnetic Materials","authors":"Hongliang Li;Philip T. Krein;Jian-Ming Jin","doi":"10.1109/JMMCT.2022.3229963","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3229963","url":null,"abstract":"A nonlinear electromagnetic (EM)-thermal coupled solver is developed for modeling ferromagnetic materials widely used in electric motors. To accurately predict machine performance, the time-domain finite element method is employed to solve this multiphysics problem. By adopting the nonlinear B-H models to account for hysteresis effects, magnetic core losses are computed as the major sources of power dissipation for magnetic materials. The resulting temperature change is then obtained and its effect on the magnetic properties is subsequently evaluated. Due to different time scales of EM field variations and heat transfer processes, different time step sizes are adopted to enhance the simulation speed. During thermal time marching, the EM solver is invoked adaptively based on material property changes, and EM losses are calculated and updated through extrapolation, resulting in an efficient EM-thermal coupling scheme. Numerical examples are presented to validate the accuracy and capabilities of the proposed EM-thermal co-simulation framework.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":"8 ","pages":"1-10"},"PeriodicalIF":2.3,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-12DOI: 10.1109/JMMCT.2022.3228281
Saurabh S. Sawant;Zhi Yao;Revathi Jambunathan;Andrew Nonaka
Modeling and characterization of electromagnetic wave interactions with microelectronic devices to derive network parameters has been a widely used practice in the electronic industry. However, as these devices become increasingly miniaturized with finer-scale geometric features, computational tools must make use of manycore/GPU architectures to efficiently resolve length and time scales of interest. This has been the focus of our open-source solver, ARTEMIS (Adaptive mesh Refinement Time-domain ElectrodynaMIcs Solver), which is performant on modern GPU-based supercomputing architectures while being amenable to additional physics coupling. This work demonstrates its use for characterizing network parameters of transmission lines using established techniques. A rigorous verification and validation of the workflow is carried out, followed by its application for analyzing a transmission line on a CMOS chip designed for a photon-detector application. Simulations are performed for millions of timesteps on state-of-the-art GPU resources to resolve nanoscale features at gigahertz frequencies. The network parameters are used to obtain phase delay and characteristic impedance that serve as inputs to SPICE models. The code is demonstrated to exhibit ideal weak scaling efficiency up to 1024 GPUs and 84% efficiency for 2048 GPUs, which underscores its use for network analysis of larger, more complex circuit devices in the future.
{"title":"Characterization of Transmission Lines in Microelectronic Circuits Using the ARTEMIS Solver","authors":"Saurabh S. Sawant;Zhi Yao;Revathi Jambunathan;Andrew Nonaka","doi":"10.1109/JMMCT.2022.3228281","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3228281","url":null,"abstract":"Modeling and characterization of electromagnetic wave interactions with microelectronic devices to derive network parameters has been a widely used practice in the electronic industry. However, as these devices become increasingly miniaturized with finer-scale geometric features, computational tools must make use of manycore/GPU architectures to efficiently resolve length and time scales of interest. This has been the focus of our open-source solver, ARTEMIS (Adaptive mesh Refinement Time-domain ElectrodynaMIcs Solver), which is performant on modern GPU-based supercomputing architectures while being amenable to additional physics coupling. This work demonstrates its use for characterizing network parameters of transmission lines using established techniques. A rigorous verification and validation of the workflow is carried out, followed by its application for analyzing a transmission line on a CMOS chip designed for a photon-detector application. Simulations are performed for millions of timesteps on state-of-the-art GPU resources to resolve nanoscale features at gigahertz frequencies. The network parameters are used to obtain phase delay and characteristic impedance that serve as inputs to SPICE models. The code is demonstrated to exhibit ideal weak scaling efficiency up to 1024 GPUs and 84% efficiency for 2048 GPUs, which underscores its use for network analysis of larger, more complex circuit devices in the future.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":"8 ","pages":"31-39"},"PeriodicalIF":2.3,"publicationDate":"2022-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-16DOI: 10.1109/JMMCT.2022.3222529
S. R. Naga Praneeth;Bhim Singh
When dealing with electromechanical system modelling, numerical challenges are inevitable. Especially when working with moving conductor problems, such as rotational or linear motors, special care needs to be taken for the air-gap region. Railguns air region is one more addition to this modelling problem. The air region necessitates either remeshing or a custom mesh topology. In addition, the production of air mesh for conductors with complicated shapes has its own difficulties. The air mesh requirement may be reduced by using the finite element-boundary element (FE-BE) technique. Boundary elements for air mesh and finite elements for conductors allow for the creation of models with moving conductors and makes model production easier and quicker. This paper investigates the changes observed in the railgun's electrical and mechanical parameters through the finite element-boundary element simulation approach when the geometry of the augmentation rails in a railgun is changed. Tapering and filleting are two geometry changes implemented on the augmenting rails of an electromagnetic railgun. Designed railgun variants are investigated using LS-Dyna software. A new formulation for breech voltage in augmented electromagnetic railguns is derived to calculate barrel efficiency. Four configurations of augmented electromagnetic railguns are analyzed, emphasizing force profile, inductance gradient, and motional-emf ( $iL^{prime }v$ ). One of the new configurations has resulted in an improvement in the force profile during the initial stages of the launch by 8.8%, and the armature's final muzzle velocity has improved by 7%.
{"title":"Finite Element-Boundary Element Method Based Simulations of Electromagnetic Railgun in Augmented Configurations","authors":"S. R. Naga Praneeth;Bhim Singh","doi":"10.1109/JMMCT.2022.3222529","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3222529","url":null,"abstract":"When dealing with electromechanical system modelling, numerical challenges are inevitable. Especially when working with moving conductor problems, such as rotational or linear motors, special care needs to be taken for the air-gap region. Railguns air region is one more addition to this modelling problem. The air region necessitates either remeshing or a custom mesh topology. In addition, the production of air mesh for conductors with complicated shapes has its own difficulties. The air mesh requirement may be reduced by using the finite element-boundary element (FE-BE) technique. Boundary elements for air mesh and finite elements for conductors allow for the creation of models with moving conductors and makes model production easier and quicker. This paper investigates the changes observed in the railgun's electrical and mechanical parameters through the finite element-boundary element simulation approach when the geometry of the augmentation rails in a railgun is changed. Tapering and filleting are two geometry changes implemented on the augmenting rails of an electromagnetic railgun. Designed railgun variants are investigated using LS-Dyna software. A new formulation for breech voltage in augmented electromagnetic railguns is derived to calculate barrel efficiency. Four configurations of augmented electromagnetic railguns are analyzed, emphasizing force profile, inductance gradient, and motional-emf (\u0000<inline-formula><tex-math>$iL^{prime }v$</tex-math></inline-formula>\u0000). One of the new configurations has resulted in an improvement in the force profile during the initial stages of the launch by 8.8%, and the armature's final muzzle velocity has improved by 7%.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":"7 ","pages":"320-327"},"PeriodicalIF":2.3,"publicationDate":"2022-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49950114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-14DOI: 10.1109/JMMCT.2022.3221835
Ozlem Ozgun;Raj Mittra;Mustafa Kuzuoglu
This paper presents an approach for evaluating the Sommerfeld integrals in the spectral domain, whose integrands typically show an oscillatory and slowly decaying behavior at high frequencies, e.g., in the mm-wave regime. It is well known that these integrals arise in the representations of the dyadic Green's functions of layered media and efficient computation of these Green's functions is key to rapid CEM modeling of patch antennas and printed circuits designed for 5G applications in the mm-wave range. The underlying concept of the approach is to partition the spectral domain representation of a Green's function into multiple domains and to represent the envelope of the integrand in each domain with a few exponentials such that the integrals in these domains can be evaluated analytically very efficiently and accurately in a numerically stable manner. Additionally, a new interpolation strategy is proposed in this work to decrease the matrix fill time in the MoM solution of the integral equations whose kernels contain Green's functions mentioned above. The performance enhancement realized by using the approaches is demonstrated through several illustrative examples.
{"title":"An Efficient Numerical Approach for Evaluating Sommerfeld Integrals Arising in the Construction of Green's Functions for Layered Media","authors":"Ozlem Ozgun;Raj Mittra;Mustafa Kuzuoglu","doi":"10.1109/JMMCT.2022.3221835","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3221835","url":null,"abstract":"This paper presents an approach for evaluating the Sommerfeld integrals in the spectral domain, whose integrands typically show an oscillatory and slowly decaying behavior at high frequencies, e.g., in the mm-wave regime. It is well known that these integrals arise in the representations of the dyadic Green's functions of layered media and efficient computation of these Green's functions is key to rapid CEM modeling of patch antennas and printed circuits designed for 5G applications in the mm-wave range. The underlying concept of the approach is to partition the spectral domain representation of a Green's function into multiple domains and to represent the envelope of the integrand in each domain with a few exponentials such that the integrals in these domains can be evaluated analytically very efficiently and accurately in a numerically stable manner. Additionally, a new interpolation strategy is proposed in this work to decrease the matrix fill time in the MoM solution of the integral equations whose kernels contain Green's functions mentioned above. The performance enhancement realized by using the approaches is demonstrated through several illustrative examples.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":"7 ","pages":"328-335"},"PeriodicalIF":2.3,"publicationDate":"2022-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49950115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：