Article
Multidisciplinary Sciences
Amos A. Hari, Sefi Givli
Summary: This paper addresses the disconnect between the importance of functional integrals in modern theories and the limited ability to perform actual calculations. The authors present a new method based on finite element formulation that overcomes the limitations of existing methods. This approach is more robust, versatile, and powerful, allowing for sophisticated computations and the study of previously unsolvable problems. Importantly, existing procedures and libraries developed in engineering analysis and partial differential equations can be directly applied to this purpose.
SCIENTIFIC REPORTS
(2023)
Article
Mathematics, Applied
Wenqiang Xiao, Bo Gong, Jiguang Sun, Zhimin Zhang
Summary: This paper presents a new method for calculating the band structure of frequency dependent photonic crystals, utilizing holomorphic Fredholm operator functions and Lagrange finite elements for discretization, along with a spectral indicator method for computing eigenvalues. Numerical examples validate the theory and demonstrate the effectiveness of the proposed approach.
JOURNAL OF SCIENTIFIC COMPUTING
(2021)
Article
Engineering, Electrical & Electronic
Yongliang Dang, Lingyu Zhu, Jiangyu Liu, Cao Zhan, Li Long, Shengchang Ji
Summary: The accurate calculation of frequency-dependent leakage inductance is crucial for the optimized design of power electronic transformers. This article proposes a module integral method based on frequency-domain energy to calculate the periodic averaged magnetic energy and provide a closed-form formula for the leakage inductance. The proposed method has a better physical interpretation compared to the previous phasor integral method and has been validated through simulation and experimental results.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Multidisciplinary Sciences
Zhen Liu, Aobo Zhang, Jiangping Xu, Cuiying Zhou, Lihai Zhang
Summary: This study proposes a settlement calculation model for soil between piles based on membrane effect, which optimizes soil bearing capacity to fully utilize it and reduce project costs.
Article
Engineering, Electrical & Electronic
Fanbing Hu, Lina Cheng, Yong Liang, Wen Wang
Summary: In this study, a precise method for calculating the sensitivity of a surface acoustic wave (SAW)-based pressure sensor was proposed. The mechanical properties of a piezoelectric diaphragm were analyzed using the Tiersten-Sinha perturbation theory and finite-element method (FEM) to achieve pressure sensitivity distribution. Various factors affecting sensitivity were taken into consideration, including material, diaphragm dimensions, and electrode position. Experimental results confirmed the high consistency between theoretical predictions and actual measurements.
IEEE SENSORS JOURNAL
(2023)
Article
Engineering, Civil
Qi Zhou, Wensheng Lu, Xiaoli Peng, Guowei Wang, Peng Zhang
Summary: In this study, a frequency formula for cable net facades considering facade stiffness is proposed. The effect of facade stiffness on the dynamic behavior is analyzed using theoretical formulas and finite element models. It is found that as the number of cable net grids increases, the influence of facade stiffness on frequency and dynamic response decreases gradually. A simplified FE model can be used when the grid number exceeds 10, while a detailed FE model is recommended when the grid number is less than 10 to avoid design errors.
Article
Engineering, Multidisciplinary
Qinyue Zhu, Quanpeng Wu, Wei Li, Minh-Trien Pham, Lixun Zhu
Summary: This article proposes a general and accurate iron loss calculation method considering harmonics based on the LS hysteresis model and FEM. The results of testing a specimen with different flux densities verify the feasibility of the modeling method. This method combines the LS model and FEM, and has been proven feasible by comparing calculated iron loss with measured data.
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS
(2021)
Article
Energy & Fuels
Haris Ataullah, Taosif Iqbal, Ihsan Ullah Khalil, Al-Sharef Mohammad, Nasim Ullah, Mohamed Emad Farrag
Summary: This article explains in detail the design of a high-frequency toroidal transformer using the ANSYS Maxwell platform. Various parameters are analyzed and validated using finite element analysis, providing guidance for optimizing transformer parameters based on leakage inductance.
Article
Engineering, Civil
Max Krause, Pawel Lyssakow, Kai-Uwe Schroeder
Summary: Stringer frame stiffened shell structures are widely used in aerospace applications due to their high load carrying capacity. However, the design of such structures is challenging and requires consideration of interdependent design variables and the computational cost of panel instability calculations. This study presents an efficient approach that improves the prediction of panel instability by modifying the structural model, converting the Ritz formulation to a finite element formulation, accounting for skin buckling effects, and using an iterative calculation routine. The suggested adjustments lead to significant improvements in the method and accurate predictions of panel instability.
THIN-WALLED STRUCTURES
(2022)
Article
Mathematics, Applied
A. Zak, W. Waszkowiak
Summary: This paper presents a new finite element method based on spline approximation polynomials, which has been computationally verified to be more accurate in high-frequency dynamics compared to traditional FEM methods. The proposed approach shows promise in accurately calculating natural frequencies and dynamic responses, making it a valuable alternative to existing FEM approaches.
COMPUTERS & MATHEMATICS WITH APPLICATIONS
(2021)
Article
Engineering, Mechanical
Chao Xu, Zhengzhong Wang, Huijun Li
Summary: In this study, the dynamic instability of frame structures is explored through the development of a direct finite element numerical simulation procedure. The results reveal that flexural-torsional vibration deformations of frames can significantly increase the size and intensity of unstable regions, posing a threat to the dynamic stability of frame structures. The proposed dynamic instability index provides an intuitive characterization of unstable regions.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2022)
Article
Engineering, Civil
Eugenio Onate, Alejandro Cornejo, Francisco Zarate, Kazuo Kashiyama, Alessandro Franci
Summary: This study presents a combined method of Finite Element Method (FEM), Particle Finite Element Method (PFEM), and Discrete Element Method (DEM) for modeling the failure of reinforced concrete structures under impulsive wave forces. Experimental validation has confirmed the potential of the new integrated approach in predicting the evolution of tsunami-type waves and their destructive effects on constructions.
ENGINEERING STRUCTURES
(2022)
Article
Engineering, Civil
Liming Zhou, Jiye Wang, Yajin Wang, Xintong Li, Yingbin Chai
Summary: The enriched finite element method (EFEM) and virtual crack closure technology (VCCT) are used in this study to model fracture mechanics problems of structures. EFEM-VCCT improves the accuracy and efficiency of standard FEM in solving fracture parameters of cracked structures. By introducing interpolation cover function, the computational efficiency and accuracy of EFEM-VCCT are further improved, as demonstrated through numerical examples.
THIN-WALLED STRUCTURES
(2023)
Article
Engineering, Electrical & Electronic
Tao Wang, Weiying Yuan, Jiansheng Yuan
Summary: This article proposes a novel 2-D semi-analytical method for the design of medium-frequency transformers (MFTs). The method is based on strict theoretical basis and has sufficient generality. It achieves high accuracy with acceptable computation cost, making it suitable for MFT designing process.
IEEE TRANSACTIONS ON MAGNETICS
(2022)
Article
Mathematics
Mislav Trbusic, Marko Jesenik, Mladen Trlep, Anton Hamler
Summary: This paper explores the magnetic levitation force experienced by a permanent magnet immersed in magnetic fluid, proposing an alternative energy method for calculating the equilibrium height. By comparing the results with a surface integral method, the proposed method shows a difference of less than 2.5%, demonstrating its accuracy in predicting stable levitation heights.
Article
Physics, Multidisciplinary
Vineeth Mohanan Parakkat, Gavin M. Macauley, Robert L. Stamps, Kannan M. Krishnan
Summary: This research demonstrates the tunability of the ground state for a hybrid artificial spin ice made of Fe nanomagnets, with three distinct magnetic textures identified by varying site-specific exchange-bias fields: a striped ferromagnetic phase, an antiferromagnetic phase achievable through external field protocols, and an unconventional ground state with magnetically charged pairs embedded in an antiferromagnetic matrix. Monte Carlo simulations support the results of field protocols and show that pinning tunes relaxation timescales and critical behavior.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Alexander Kovacs, Lukas Exl, Alexander Kornell, Johann Fischbacher, Markus Hovorka, Markus Gusenbauer, Leoni Breth, Harald Oezelt, Dirk Praetorius, Dieter Suess, Thomas Schrefl
Summary: Physics informed neural networks can be used to solve partial differential equations and variational problems related to magnetic fields, by approximating the unknown field with neural networks. This method can be applied to estimate magnetic flux density, solve inverse magnetostatic problems, and address micromagnetic problems.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
S. Perna, F. Bruckner, C. Serpico, D. Suess, M. d'Aquino
Summary: This paper proposes a new method for micromagnetic simulations, using normal modes to describe the dynamics of magnetic nanostructures and optimize the system response to external excitations. The validity and computational speed of this method are demonstrated through case studies in different scenarios.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
S. Perna, F. Bruckner, C. Serpico, D. Suess, M. D'Aquino
Summary: The spatially-inhomogeneous magnetization dynamics in a cylindrical magnetic nanodot driven by ac spin-torque is analyzed. The Landau-Lifshitz-Gilbert-Slonczewski equation is reformulated as a system of coupled nonlinear ordinary differential equations describing the time-evolution of normal modes amplitudes. This approach provides a class of models with reduced degrees of freedom and incremental accuracy between macrospin and full micromagnetics.
Article
Physics, Multidisciplinary
Christian Wessler, Bertrand Roessli, Karl W. Kraemer, Uwe Stuhr, Andrew Wildes, Hans B. Braun, Michel Kenzelmann
Summary: Magnonic devices are a potential alternative for information processing and storage, and van der Waals crystals are promising materials for such applications. In this study, the authors investigate the magnetic properties of ErBr3 and find that the dipolar interactions allow for continuous control of topological excitations, which is important for the development of topological magnon insulators.
COMMUNICATIONS PHYSICS
(2022)
Article
Engineering, Electrical & Electronic
Florian Slanovc, Dieter Suesse, Michael Ortnere
Summary: This paper addresses the topic of magnetic linear position detection and proposes a method to improve the airgap stability by adding a second magnet. The results show that this method can significantly reduce measurement errors for both 1-D and 2-D systems.
IEEE TRANSACTIONS ON MAGNETICS
(2022)
Article
Physics, Applied
Rehana Begum Popy, Julia Frank, Robert L. Stamps
Summary: In this study, the possible magnetic behaviors of bilayer artificial spin ice are examined using numerical simulations. The impact of long-range dipolar coupling on magnetization dynamics is investigated by varying the layer separation and rotation. Unusual magnetic ordering is predicted for certain angles that define lateral spin superlattices in the bilayer systems.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
J. Iyaro, R. L. Stamps
Summary: This paper examines excitations that may appear in cavity magnonics experiments using numerical micromagnetics and a recently developed semi-classical cavity magnonics theory. The theory, which is applicable to linear and nonlinear dynamic systems, is demonstrated through example applications for magnetic systems described by numerical micromagnetics. The effects of large amplitude driving and elliptically polarized driving fields are also studied. The main conclusion is that the theory, when combined with micromagnetics, offers a useful technique for describing cavity photon-magnon coupling for a wide range of linear and nonlinear magnetic dynamics.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
D. Wang, Hans-Benjamin Braun, Yan Zhou
Summary: This article introduces the research on the inertia problem of magnetic skyrmions in motion. By considering the coupling between skyrmion motion and magnons, the dynamic mass of the skyrmion is determined, and the engineering of skyrmion dynamics with magnons through material and geometry design is discussed.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Physics, Applied
Zachary R. Nunn, Juliana Besler, Pavlo Omelchenko, Sabri Koraltan, Claas Abert, Dieter Suess, Erol Girt
Summary: We demonstrate that a noncollinear alignment between magnetizations of adjacent ferromagnetic layers can be achieved by coupling two ferromagnetic layers across a magnetic spacer layer consisting of a nonmagnetic material, Ru, alloyed with a ferromagnetic element, Co. The relative angle between the magnetizations of the ferromagnetic layers can be controlled by changing the composition and thickness of the spacer layer between 0 degrees and 180 degrees.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
D. Suess, S. Koraltan, F. Slanovc, F. Bruckner, C. Abert
Summary: Within this paper, we demonstrate the significance of accurate implementations of RKKY interactions for antiferromagnetically coupled ferromagnetic layers with thicknesses larger than the exchange length. We develop a benchmark problem to evaluate different implementations of RKKY interaction by deriving an analytical formula for the saturation field of two infinitely thick antiparallelly coupled magnetic layers. Our benchmark problem reveals that current implementations in commonly used finite-difference codes lead to errors in the saturation field, exceeding 20% for mesh sizes of 2 nm, which is below the material's exchange length. To enhance accuracy, we introduce higher order cell-based and nodal-based finite-difference codes that significantly reduce errors compared to existing implementations. With a mesh size of 2 nm, the second-order cell-based approach and the first-order nodal-based approach reduce the error in the saturation field by a factor of 10 (2% error).
Article
Materials Science, Multidisciplinary
Santiago Helbig, Claas Abert, Pedro A. Sanchez, Sofia S. Kantorovich, Dieter Suess
Summary: We propose a simple simulation model to study magnetic and frictional losses of magnetic nanoparticles in viscous fluids under alternating magnetic fields. The model is based on a macrospin approach and solves the Landau-Lifshitz-Gilbert equation coupled with the mechanical torque equation. Despite its simplicity, the model reveals rich physics and allows for a detailed analysis of different loss processes depending on field parameters and initial particle-field arrangement. The model demonstrates the emergence of different steady states depending on these parameters, with regions dominated by magnetic relaxation and high losses or high frictional losses at low fields or frequencies. The energy continuously increases even across regime boundaries, surpassing the viscous relaxation limit. At higher frequencies, the steady state can also depend on the initial particle orientation in the external field. We compare and discuss the general behavior and specific absorption rates for different cases.
Article
Materials Science, Multidisciplinary
Markus Gattringer, Claas Abert, Florian Bruckner, Andrii Chumak, Dieter Suess
Summary: We propose a nanoscopic numerical model of spin pumping, which incorporates spin-torque effects and extends a spin-diffusion solver. This model is fully integrated within a micromagnetics finite-element framework. Our results demonstrate that the model accurately replicates analytical solutions for standard problems and properly models the Gilbert damping of propagating magnons. Utilizing this model, we can examine spin-pumping effects, as well as the resulting inverse spin Hall effect, on a nanoscopic scale.
Article
Materials Science, Multidisciplinary
Igor Proskurin, Jephthah O. Iyaro, Robert L. Stamps
Summary: This research demonstrates the realization of level attraction phenomenon in a Floquet system with memory and provides an example in cavity magnonics, showing that magnetic excitations in systems driven far from equilibrium may show level attraction with cavity photons.
Article
Materials Science, Multidisciplinary
Peter Flauger, Claas Abert, Dieter Suess
Summary: In this study, we propose an efficient strategy to simulate magnetization switching in magnetic tunnel junctions using a micromagnetic model and a matrix-based nonequilibrium Green's function algorithm. Simulation results with realistic parameters show that the switching time is below 4 ns for voltages above 300 mV or around 2 x 10(10) A m(-2) for the P -> AP direction. For AP -> P switching, there is a reversal in the trend of the switching time, with the time first decreasing and then increasing with increasing bias voltage.
