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Novel methods for determining rupture risk in abdominal aortic aneurysms (AAAs) have focused primarily on CT-based wall stress analysis using finite element models (FEMs). Recent studies have demonstrated ultrasound (US) based FEM, and the possibility of using inverse FEM analysis: matching displacements between the models and US to find patient specific aortic stiffness. This requires an accurate...
This paper presents a comparative study on two analytical modelling techniques (i.e. Fourier analysis and Tooth Contour Method), applied to a benchmark topology of a linear permanent magnet synchronous motor (LPMSM). The investigated methods are used for obtaining the thrust force of a LPMSM with significantly reduced computation time (from the order of seconds to the order of milliseconds), compared...
Finite element method (FEM) has been extensively used for analyzing both static and dynamic behaviour of CMUTs. Typical parameters being evaluated include the pull-in voltage, pressure, sensitivity, bandwidth, and crosstalk. PZFlex is a commercial FEA software and has been optimized for the ultrasound industry and is commonly used to design piezo-electric ultrasound transducers. However, PZFlex is...
In order to calculate the copper loss calculation with coil end effect in a practical computation time, the zooming method, which is one of the model reduction methods, is applied to the analysis of an three-phase synchronous motor. Moreover, the faster calculation technique is proposed for the analysis of three-phase synchronous motor. The copper loss of litz wire with a coil end can be calculated...
Grain-boundary scattering of acoustic waves in polycrystalline materials is studied with analytical and numerical methods in the presented paper. In particular, the attenuation of Surface Acoustic Waves (SAWs) propagating through a polycrys-talline microstructure is investigated. A three dimensional timedomain finite-element method (FEM) is utilized for the numerical simulation, whereby the granular...
Harmonic finite element simulations are widely used to model the steady-state linear response of acoustic devices such as resonators and ultrasonic transducers; however, the underlying formulation assumes constant (or frequency-dependent) material properties, and thus cannot be used to model the nonlinearities imparted by phenomena such as strain or temperature dependent constitutive behavior. The...
This paper deals with an analysis of the design parameters and its influence on performance of the linear induction motor (LIM). LIM propels using Lorentz force generated by interaction between magnetic flux of the primary and eddy current induced in secondary. As depending on the size of the primary and the secondary, not only magnetic flux and induced eddy current, but also performances of the LIM...
A standard quality control in the production of wood based materials is the check for delaminations, caused by air inclusions in the material. Plates with delaminations have the risk to burst in the later process or to break, when they are used. A proven measurement method for several decades is the detection by means of air-coupled ultrasound. The defects are identified by the attenuation of the...
Using analytical calculations, a precise large signal equivalent circuit model of square CMUT dynamics was developed. The model predicts many intrinsic properties of a square CMUT cell including resonance frequency, phase and magnitude of the membrane displacement, membrane velocity, electrical conductance, collapse voltage, etc. ANSYS 3D finite element analysis (FEA) was used to validate the equivalent...
Electrospinning is an experimental method of the polymer super thin fibres formation by the electrostatic field. The distribution of electrostatic field affects the effectiveness of the electrospinning. In order to analyze the electrostatic field for given technological parameters the 3-D computer model of an electrospinning device is necessary.
Induction machines for traction applications are operated at working points of high ferromagnetic saturation. Depending on the working point, a broad spectrum of harmonic frequencies appears in the magnetic flux density of induction machines. Detailed loss analysis therefore requires local and temporal highly resolved nonlinear field computation. This loss analysis could be performed in the post processing...
PZFlex is a commercial FEA software that has been optimized for the ultrasound industry and is commonly used to design piezoelectric ultrasound transducers. However, PZFlex is not commonly used within the CMUT research field. Nevertheless, it has an explicit modeling approach allowing large structures like CMUT arrays to be modeled and its transient analysis intrinsically supplies non-linear and broadband...
An accurate nonlinear lumped equivalent circuit model is used for modeling of capacitive micromachined Ultrasonic Transducers (CMUTs). Finite element analysis (FEA) is a powerful tool for the analysis of CMUT arrays with a few number of cells while with the equivalent circuit model, the entire behavior of a large-scale arbitrary CMUT array can be modelled in a very short time. Recently, an accurate...
This study models induced electric fields, and their gradient, produced by pulsatile current stimulation of submillimeter inductors for cochlear implantation. Using finite-element analysis, the lower chamber of the cochlea, scala tympani, is modeled as a cylindrical structure filled with perilymph bounded by tissue, bone, and cochlear neural elements. Single inductors as well as an array of inductors...
High-voltage disconnectors are the largest and most important primary device in the transformer substation. There are many problems during the closing of the disconnector, such as not in place, over the place, the contactor is loose and so on. This paper presents the Finite Element Analysis (FEA) of disconnector GW4D-126D(W) under different closing states performed by ANSYS Workbench. The experimental...
In this paper, a proposed analytical model is introduced for acceptable optimization of an axial flux permanent magnet (AFPM) machines. Nowadays the finite-element model is one of the most powerful tool to analysis the electrical machine. However, sometimes this method can be very time-consuming for further optimization. Therefore, in this paper, a hybrid analytical model based on sub-domain algorithm...
In this paper, a novel analytical method is proposed to predict the air-gap magnetic field distribution of surface mounted permanent magnet machine (SMPMM) with non-concentric magnetic pole (NCMP). The NCMP is parted into two sub-regions with different shapes in the radial direction, the magnetic field of which can be analyzed using different analytical models in the polar coordinate system. The governing...
Electrical and mechanical faults in a three phase Induction machine is modelled and analysed, to identify potential fault signatures. Electrical, magnetic and torque signatures are analysed for various faults and their combinations, for potential fault signature identification. A multi-physics Finite Element tool is chosen for this analysis considering the possibilities to extend the study to thermal...
This paper presents a diagnosis method of stator inter-turn short-circuits in self-excited power alternators. First, a new way to accurately model power alternators is depicted. Thanks to a co-simulation process between Flux2D and Matlab, this model of a healthy alternator is able to faithfully reproduce the waveforms of the signals in the system and therefore their harmonic contents. This information...
In this study three-dimensional finite analysis models of 3D micro-scale chip scale package (CSP) solder joints were set up. The stress-strain distribution of micro-scale CSP solder joints was obtained by finite element analysis under the condition of random vibration load. The influence of different solder, pad diameter and solder joint volume on the stress-strain of micro-scale CSP solder joint...
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