Harmonic balanced Jiles-Atherton hysteresis implementation for finite element simulation

2017 ◽  
Vol 36 (5) ◽  
pp. 1386-1395 ◽  
Author(s):  
Markus Wick ◽  
Matthias Jüttner ◽  
Wolfgang M. Rucker
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Frequency Domain ◽  
Fourier Transforms ◽  
Jacobian Matrix ◽  
Material Model ◽  
Fast Method ◽  
Material Models ◽  
Content Type ◽  
Magnetic Devices

Purpose The high calculation effort for accurate material loss simulation prevents its observation in most magnetic devices. This paper aims at reducing this effort for time periodic applications and so for the steady state of such devices. Design/methodology/approach The vectorized Jiles-Atherton hysteresis model is chosen for the accurate material losses calculation. It is transformed in the frequency domain and coupled with a harmonic balanced finite element solver. The beneficial Jacobian matrix of the material model in the frequency domain is assembled based on Fourier transforms of the Jacobian matrix in the time domain. A three-phase transformer is simulated to verify this method and to examine the multi-harmonic coupling. Findings A fast method to calculate the linearization of non-trivial material models in the frequency domain is shown. The inter-harmonic coupling is moderate, and so, a separated harmonic balanced solver is favored. The additional calculation effort compared to a saturation material model without losses is low. The overall calculation time is much lower than a time-dependent simulation. Research limitations/implications A moderate working point is chosen, so highly saturated materials may lead to a worse coupling. A single material model is evaluated. Researchers are encouraged to evaluate the suggested method on different material models. Frequency domain approaches should be in favor for all kinds of periodic steady-state applications. Practical implications Because of the reduced calculation effort, the simulation of accurate material losses becomes reasonable. This leads to a more accurate development of magnetic devices. Originality/value This paper proposes a new efficient method to calculate complex material models like the Jiles-Atherton hysteresis and their Jacobian matrices in the frequency domain.

Motion in frequency domain for harmonic balance simulation of electrical machines

2018 ◽  
Vol 37 (4) ◽  
pp. 1449-1460
Author(s):  
Markus Wick ◽  
Sebastian Grabmaier ◽  
Matthias Juettner ◽  
Wolfgang Rucker
Keyword(s):  
Steady State ◽  
Frequency Domain ◽  
Efficient Method ◽  
Harmonic Balance ◽  
Eddy Currents ◽  
Computational Effort ◽  
Electrical Machines ◽  
Accurate Approximation ◽  
Content Type ◽  
Magnetic Devices

Purpose The high computational effort of steady-state simulations limits the optimization of electrical machines. Stationary solvers calculate a fast but less accurate approximation without eddy-currents and hysteresis losses. The harmonic balance approach is known for efficient and accurate simulations of magnetic devices in the frequency domain. But it lacks an efficient method for the motion of the geometry. Design/methodology/approach The high computational effort of steady-state simulations limits the optimization of electrical machines. Stationary solvers calculate a fast but less accurate approximation without eddy-currents and hysteresis losses. The harmonic balance approach is known for efficient and accurate simulations of magnetic devices in the frequency domain. But it lacks an efficient method for the motion of the geometry. Findings The three-phase symmetry reduces the simulated geometry to the sixth part of one pole. The motion transforms to a frequency offset in the angular Fourier series decomposition. The calculation overhead of the Fourier integrals is negligible. The air impedance approximation increases the accuracy and yields a convergence speed of three iterations per decade. Research limitations/implications Only linear materials and two-dimensional geometries are shown for clearness. Researchers are encouraged to adopt recent harmonic balance findings and to evaluate the performance and accuracy of both formulations for larger applications. Practical implications This method offers fast-frequency domain simulations in the optimization process of rotating machines and so an efficient way to treat time-dependent effects such as eddy-currents or voltage-driven coils. Originality/value This paper proposes a new, efficient and accurate method to simulate a rotating machine in the frequency domain.

Numerical Analysis of the Influence of Material Model on Response of Compressed Imperfect Thin-Walled Channel

2014 ◽  
Vol 611 ◽  
pp. 188-193 ◽  
Author(s):  
Vladimír Ivančo ◽  
Gabriel Fedorko ◽  
Ladislav Novotný
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Model Selection ◽  
Finite Element Model ◽  
Material Model ◽  
Element Model ◽  
Material Models ◽  
Geometric Imperfections ◽  
Walled Channel ◽  
Thin Walled

In the paper, the influence of material model selection on the behaviour of Finite Element model of a compressed thin-walled channel is studied. Results of three material models of channels of two different lengths and two types of geometric imperfections are compared and discussed.

Finite Element Analysis of a Steady-State Rotating Tire Subjected to Point Load or Ground Contact

1987 ◽  
Vol 15 (4) ◽  
pp. 243-260 ◽  
Author(s):  
R. Kennedy ◽  
J. Padovan
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Contact Point ◽  
Three Dimensional ◽  
Static Problem ◽  
Material Model ◽  
Point Load ◽  
Ground Contact ◽  
Element Analysis ◽  
Automobile Tire

Abstract A radial automobile tire undergoing steady-state rotation is analyzed by a finite element method. A special formulation is used which allows the finite element equations to be solved as a quasi-static problem using static analysis solution procedures, rather than as a dynamic problem requiring solution in the time domain. This is accomplished through a transformation of variable that changes time derivatives, present through inertia, to spatial derivatives. Solution time for the analysis is thereby shortened. The tire is modeled first as a two-dimensional ring on an elastic foundation, then in its full three-dimensional geometry. Rotational speeds are those at which resonance occurs so that the dynamics can be easily visualized and the response easily verified. The models are subjected to point load excitation or ground contact. Point load is used to predict resonance responses of the undamped tire. Results agreed well with experimental measurements. The effect of inertia components and damping on vibrational response of the tire was studied by imposing ground contact at one of the resonance speeds. Damping is included in the model through a two-element Kelvin-Voight viscoelastic material model. Responses of the models were similar to standing wave deformations in a tire.

scholarly journals COMPARISON OF VIRTUAL FIELDS METHOD, PARALLEL NETWORK MATERIAL MODEL AND FINITE ELEMENT UPDATING FOR MATERIAL PARAMETER DETERMINATION

2016 ◽  
Vol 7 ◽  
pp. 7
Author(s):  
Florian Dirisamer ◽  
Umut D. Çakmak ◽  
Imre Kállai ◽  
Martín Machado ◽  
Zoltán Major
Keyword(s):  
Finite Element ◽  
Material Model ◽  
Image Correlation ◽  
Parameter Determination ◽  
Virtual Fields Method ◽  
Material Models ◽  
Time Frequency ◽  
Parallel Network ◽  
Experimental Effort ◽  
Frequency Temperature

Extracting material parameters from test specimens is very intensive in terms of cost and time, especially for viscoelastic material models, where the parameters are dependent of time (frequency), temperature and environmental conditions. Therefore, three different methods for extracting these parameters were tested. Firstly, digital image correlation combined with virtual fields method, secondly, a parallel network material model and thirdly, finite element updating. These three methods are shown and the results are compared in terms of accuracy and experimental effort.

Rotor-dynamic performance of porous hydrostatic thrust bearing operating under magnetic field

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Vivek Kumar ◽  
Vatsalkumar Ashokkumar Shah ◽  
Simran Jeet Singh ◽  
Kuldeep Narwat ◽  
Satish C. Sharma
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Steady State ◽  
Magnetic Fluid ◽  
Reynolds Equation ◽  
Thrust Bearing ◽  
Dynamic Performance ◽  
Performance Indices ◽  
Content Type ◽  
Rotor Dynamic

Purpose The porous bearings are commonly used in slider thrust bearings owing to their self-lubricating properties and cost effectiveness as compared to conventional hydrodynamic bearings. The purpose of this paper is to numerically investigate usefulness of porous layer in hydrostatic thrust bearing operating with magnetic fluid. The effect of magnetic field and permeability has been analysed on steady-state (film pressure, film reaction and lubricant flow rate) and rotor-dynamic (stiffness and damping) parameters of bearing. Design/methodology/approach Finite element approach is used to obtain numerical solution of flow governing equations (Magneto-hydrodynamics Reynolds equation, Darcy law and capillary equation) for computing abovementioned performance indices. Finite element method formulation converts elliptical Reynolds equation into set of algebraic equation that are solved using Gauss–Seidel method. Findings It has been reported that porosity has limited but adverse effects on performance parameters of bearing. The adverse effects of porosity can be minimized by using a circular pocket for achieving better steady-state response and an annular/elliptical pocket, for having better rotor-dynamic response. The use of magnetic fluid is found to be substantially enhancing the fluid film reaction (53%) and damping parameters (55%). Practical implications The present work recommends use of circular pocket for achieving better steady-state performance indices. However, annular and elliptical pockets should be preferred, when design criteria for the bearing are better rotor-dynamic performance. Originality/value This study deals with influence of magnetic fluid, porosity and pocket shape on rotor-dynamic performance of externally pressurized thrust bearing. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0289/

Non-Newtonian numerical modelling of solder paste viscosity measurement

2019 ◽  
Vol 31 (3) ◽  
pp. 176-180 ◽  
Author(s):  
Tareq I. Al-Ma’aiteh ◽  
Oliver Krammer
Keyword(s):  
Apparent Viscosity ◽  
Material Model ◽  
Viscosity Measurement ◽  
Solder Paste ◽  
Material Models ◽  
Stencil Printing ◽  
Content Type ◽  
Shear Rates ◽  
Paste Viscosity ◽  
Measured Viscosity

PurposeThe purpose of this paper is to present the establishment of a computational fluid dynamics model for investigating different non-Newtonian rheological models of solder pastes by simulating solder paste viscosity measurement. A combined material model was established which can follow the measured, apparent viscosity values with lower error.Design/methodology/approachThe model included a parallel plate arrangement of rheometers. The diameter of the plate was 50 mm, whereas the gap between the plates was 0.5 mm. Only one quarter of the plate was modelled to enable using fine enough mesh, while keeping the calculation time low. Non-Newtonian properties were set using user defined function in Ansys, based on the Cross and Carreau–Yasuda material models. The viscosity values predicted by the mathematical models were compared to measured viscosity values of different types of solder pastes.FindingsIt was found that the Cross model predicts the apparent viscosity with a relatively high error (even approximately 50 per cent) at lower shear rates, whereas the Carerau–Yasuda model has higher errors at higher shear rates. The application of the proposed, combined model can result in a much lower error in the apparent viscosity between the calculated and measured viscosity values.Originality/valueThe error of Cross and Carreau–Yasuda material models has not been investigated yet in details. The proposed, combined material model can be applied for subsequent simulations via the described UDF, e.g. in the numerical modelling of the stencil printing. This can result in a more accurate modelling of the stencil printing process, which is inevitable considering the printing of solder paste for today fine-pitch, small size components.

Influence of Material Model on Tensile Loaded Joint

2010 ◽  
Vol 165 ◽  
pp. 394-399 ◽  
Author(s):  
E. Szymczyk ◽  
Grzegorz Slawinski
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Numerical Analysis ◽  
Stress Field ◽  
Material Model ◽  
Finite Element Simulations ◽  
Residual Stress Field ◽  
Material Models ◽  
Riveted Joint ◽  
Load Conditions

The paper deals with the numerical analysis of a tensile loaded riveted joint. Finite element simulations of the upsetting process were carried out with the use of Marc code to determine the residual stress field. The contact with friction is defined between the mating parts of the joint. The computations were performed for four cases of material and load conditions and a comparison was performed on the basis of results obtained for standard elasto plastic and Gurson material models. Moreover, the influence of material model and residual stress on the tensile loaded joint was analyzed.

Thermomechanical modeling of fiber reinforced material including interphasial properties and its application to epoxy/glass composites

2016 ◽  
Vol 33 (4) ◽  
pp. 1259-1281 ◽  
Author(s):  
Marko Bozic ◽  
Robert Fleischhauer ◽  
Michael Kaliske
Keyword(s):  
Finite Element ◽  
Numerical Solutions ◽  
Initial Boundary ◽  
Material Model ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Theoretical Formulation ◽  
Content Type ◽  
Fiber Reinforced Material ◽  
Initial Boundary Value

Purpose – The purpose of this paper is to investigate of interphasial effects, including temperature dependency, within fiber reinforced polymers on the overall composite behavior. Providing theoretical and numerical approaches in terms of a consistent thermomechanical finite element method framework are further goals of this research. Design/methodology/approach – Starting points for achieving the aims of this research are the partial differential equations describing the evolution of the displacements and temperature within a continuum mechanical setting. Based on the continuous formulation of a thermomechanical equilibrium, constitutive equations are derived, accounting for the modeling of fiber reinforced thermosets and thermoplastics, respectively. The numerical solutions of different initial boundary value problems are obtained by a consistent implementation of the proposed formulations into a finite element framework. Findings – The successful theoretical formulation and numerical modeling of the thermoinelastic matrix materials as well as the thermomechanical treatment of the composite interphase (IP) are demonstrated for an epoxy/glass system. The influence of the IP on the overall composite behavior is successfully investigated and concluded as a further aspect. Originality/value – A thermomechanical material model, suitable for finite thermoinelasticity of thermosets and thermoplastics is introduced and implemented into a novel kinematic framework in context of the inelastic deformation evolution. The gradually changing material properties between the matrix and the fiber of a composite are continuously formulated and numerically processed, in order to achieve an efficient and realistic approach to model fiber reinforced composites.

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