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Study of the behavior of TORP middle ear prostheses of various lengths by the finite element method

MECHANICS OF ADVANCED MATERIALS AND STRUCTURES 2024年

作者： Omar, Khatir Mohamed, Fekih Sidi Hamada, Atef Abderahmene, Sahli Yaylaci, Murat Abdelkader, Benkhettou Ismail, Boudjemaa Tahraoui, Adel Bouiadjraa, Belabbes Bachir Univ Djillali Liabes Sidi Bel Abbes Dept Mech Engn Sidi Bel Abbes Algeria Univ Oulu Kerttu Saalasti Inst Future Mfg Technol FMT Nivala Finland Recep Tayyip Erdogan Univ Biomed Engn MSc Program Rize Turkiye Recep Tayyip Erdogan Univ Dept Civil Engn Rize Turkiye Recep Tayyip Erdogan Univ Turgut Kiran Maritime Fac Rize Turkiye Univ Sci & Technol Oran Mohamed Boudiaf USTO MB Fac Mech Engn Oran Algeria Taleb Mourad Univ Sidi Bel Abbes Fac Med Dept ENT Sidi Bel Abbes Algeria

Advancements in audiology and medical engineering have sparked growing interest in enhancing titanium implants used for middle ear repair. In our study, we employed a numerical simulation model of the middle ear to investigate how the TORP prosthesis behaves under an acoustic pressure of 90 dB across a frequency range from 250 to 8000 Hz. Additionally, we varied the prosthesis length, utilizing three different lengths, and modified the prosthesis design to assess its mechanical impact. Our findings indicate that changes in prosthesis length do not significantly alter outcomes for patients. Moreover, these variations do not pose any danger or compromise the auditory performance of patients, emphasizing the safety and efficacy of TORP prostheses in middle ear repair.

关键词： Middle ear ossicles prosthesis vibration analysis finite-element method

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Adjoint-Based Accelerated Adaptive Refinement in Frequency Domain 3-D finite element method Scattering Problems

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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 2021年第2期69卷 940-949页

作者： Harmon, Jake J. Key, Cam Estep, Donald Butler, Troy Notaros, Branislav M. Colorado State Univ Dept Elect & Comp Engn Ft Collins CO 80523 USA Colorado State Univ Dept Stat Ft Collins CO 80523 USA Univ Colorado Dept Math & Stat Sci Denver CO 80204 USA

We present the application of adjoint analysis to 3-D finite-element method scattering problems for a posteriori error estimation and adaptive refinement. Adjoint-based methodologies, though underutilized in computational electromagnetics (CEM), enable significant improvements for both efficiency and accuracy. We first formulate the adjoint problem of the 3-D double-curl wave equation and the error estimates for the construction of novel accelerated adaptive refinement algorithms. We demonstrate adaptive error control for a customizable quantity of interest (QoI) resulting in targeted refinement and improved resource allocation through the application of automatic global and local error tolerance heuristics that accelerate the refinement process. The proposed refinement algorithms rapidly refine even extremely coarse initial discretizations to high accuracy, eliminating or substantially reducing manual intervention in the generation of computationally efficient and accurate simulations. Moreover, comparisons with analytical results validate our approach to accelerating automatic refinement to fine tolerances.

关键词： A posteriori error analysis adaptive error control adaptive mesh refinement adjoint methods computational electromagnetics (CEM) error estimation finite-element method frequency domain

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Identification of mechanical parameters of urea-formaldehyde microcapsules using finite-element method

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COMPOSITES PART B-ENGINEERING 2019年第Feb.1期158卷 249-258页

作者： Wang, X. F. Han, R. Tao, J. Han, T. L. Zhu, G. M. Tang, J. N. Han, N. X. Xing, F. Shenzhen Univ Coll Civil Engn Guangdong Prov Key Lab Durabil Marine Civil Engn Shenzhen 518060 Peoples R China Shenzhen Univ Coll Mat Sci & Engn Shenzhen 518060 Peoples R China

To obtain the mechanical parameters for a microcapsule, such as the Young's modulus, yield stress, and hardening coefficients using different mechanical constitutive models, parameter identification must be implemented using inverse analysis. In the present study, a new approach combining the finite-element method and an optimisation procedure is proposed for determining the constitutive parameters of urea-formaldehyde micro capsules, in which three types of elastic-plastic constitutive models are considered: the power-law hardening model, the elastic-perfectly plastic model, and the elastic-perfectly plastic model with linear hardening. A nonlinear optimisation procedure is applied to determine the minimum of the multivariable objective function, which is defined as the norm of the difference between the numerical and experimental results. The efficiency and robustness of the proposed method are verified with different initial values and numbers of elements. The force-displacement curves from a numerical simulation show good agreement with the experimental data, indicating that the proposed approach and the mechanical parameters determined are reliable.

关键词： Parameter identification Microcapsule Inverse analysis Elastic-plastic model finite-element method

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High-Order Unconditionally Stable Time-Domain finite-element method

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IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS 2019年第9期18卷 1775-1779页

作者： Taggar, Karanvir Gad, Emad McNamara, Derek Univ Ottawa Sch Elect Engn & Comp Sci Ottawa ON K1N 6N5 Canada

This letter presents a new approach for finite-element time-domain electromagnetic analysis. The new method combines the property of high-order approximation in the time domain with the crucial property of unconditional stability. The proposed method has been used in circuit simulation and relies on employing a specific formulation of the numerical inversion of the Laplace transform. The method is validated using one- and two-dimensional scattering from a dielectric object.

关键词： Computational electromagnetics finite element analysis finite-element method high-order time domain unconditional stability

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finite element method for the quasiclassical theory of superconductivity

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Physical Review B 2022年第14期106卷 144511-144511页

作者： Kevin Marc Seja Tomas Löfwander Department of Microtechnology and Nanoscience–MC2 Chalmers University of Technology SE-41296 Göteborg Sweden

The Eilenberger-Larkin-Ovchinnikov-Eliashberg quasiclassical theory of superconductivity is a powerful method enabling studies of a wide range of equilibrium and nonequilibrium phenomena in conventional and unconventional superconductors. We introduce here a finite element method, based on a discontinuous Galerkin approach, to self-consistently solve the underlying transport equations for general device geometries, arbitrary mean free path, and symmetry of the superconducting order parameter. We present results on (i) the influence of scalar impurity scattering on phase crystals in d-wave superconducting grains at low temperatures and (ii) the current flow and focusing in d-wave superconducting weak links, modeling recent experimental realizations of grooved high-temperature superconducting Dayem bridges. The high adaptability of this finite element method for quasiclassical theory paves the way for future investigations of superconducting devices and new physical phenomena in unconventional superconductors.

关键词： Superconductivity d-wave finite-element method methods in superconductivity methods in transport

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Modelling the Soft Robot Kyma Based on Real-Time finite element method

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COMPUTER GRAPHICS FORUM 2020年第6期39卷 289-302页

作者： Martin-Barrio, A. Terrile, S. Diaz-Carrasco, M. del Cerro, J. Barrientos, A. Univ Politecn Madrid Ctr Automat & Robot CSIC Madrid Spain

Modelling soft robots is a non-trivial task since their behaviours rely on their morphology, materials and surrounding elements. These robots are very useful to safely interact with their environment and because of their inherent flexibility and adaptability skills. However, they are usually very hard to model because of their intrinsic non-linearities. This fact presents a unique challenge in the computer graphics and simulation scopes. Current trends in these fields tend to narrow the gap between virtual and real environments. This work will explain a challenging modelling process for a cable-driven soft robot called Kyma. For this purpose, the real-time finite element method (FEM) is applied using the Simulation Open Framework Architecture. And two methods are implemented and compared to optimize the model efficiency: a heuristic one and the Model Order Reduction. Both models are also validated with the real robot using a precise motion tracking system. Moreover, an analysis of robot-object interactions is proposed to test the compliance of the presented soft manipulator. As a result, the real-time FEM emerges as a good solution to accurately and efficiently model the presented robot while also allowing to study the interactions with its environment.

关键词： modeling simulation soft robots interaction finite-element method

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Assessing multisensor radiofrequency-based through-the-wall mapping systemic parameters using a finite-element method framework

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JOURNAL OF APPLIED REMOTE SENSING 2018年第2期12卷

作者： Campos, Rafael Saraiva Lovisolo, Lisandro de Campos, Marcello Luiz R. CEFET RJ Petropolis Brazil PEL DETEL FEN UERJ Rio De Janeiro Brazil COPPE UFRJ Rio De Janeiro Brazil

Radiofrequency (RF) through-the-wall mapping (TWM) employs techniques originally applied in x-ray computerized tomographic imaging to map obstacles behind walls. It aims to provide valuable information for rescuing efforts in damaged buildings, as well as for military operations in urban scenarios. This work defines a finite-element method (FEM) based framework to allow fast and accurate simulations of the reconstruction of floor blueprints, using very high-frequency signals. To the best of our knowledge, this is the first use of FEM in a TWM scenario. This framework allows quick evaluation of different algorithms without the need to assemble a full test setup, which might not be available due to budgetary and time constraints. Using this, the present work evaluates a collection of reconstruction methods under a parallel-beam acquisition geometry for different spatial sampling rates, number of projections, antenna gains, and operational frequencies. This work also proposes a multisensor circular acquisition geometry, which is expected to reduce acquisition time and thus enable the detection of floor layout changes (e.g., the opening and closing of a door). Considering all the drawbacks associated with such a complex problem, a robust and reliable computational setup based on a flexible method, such as FEM, can be very useful. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： reconstruction algorithms finite-element method through-the-wall mapping multi-sensor acquisition scheme

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Design and performance analysis of magnetic slot wedge application in double-fed asynchronous motor-generator by finite-element method

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IET ELECTRIC POWER APPLICATIONS 2018年第7期12卷 1040-1047页

作者： Xiao, Yang Zhou, Libing Wang, Jin Liu, Jianjun Huazhong Univ Sci & Technol Sch Elect & Elect Engn State Key Lab Adv Electromagnet Engn & Technol Wuhan Hubei Peoples R China Dongfang Elect Machinery Co Ltd Dongfang Elect Corp Deyang Peoples R China

In this study, an improvement method for double-fed asynchronous motor-generators (DFAMG) design with open slots is proposed to reduce the capacity demand of rotor converter for the first time. The proposed method is achieved by decreasing the air-gap length (AGL) and applying conductive and magnetic rotor slot wedges. The design method of magnetic slot wedges and AGL in large DFAMG is presented. The mechanical analysis of a large DFAMG prototype reveals the necessity of using metal rotor wedges. To precisely investigate the influence of magnetic wedges in DFAMG, a two-dimensional field-circuit coupled model is proposed to consider the effects of rotor converter. Several wedge configurations of commercially available products are designed and analysed. The relationships between the electromagnetic properties of rotor wedges and prototype performance are investigated. The feasibility and advantage of the proposed method in DFAMG design are verified. A guidance for applying the proposed method in design improvement of large DFAMG is developed.

关键词： induction motors rotors finite element analysis performance analysis magnetic slot wedge application double-fed asynchronous motor-generator finite-element method improvement method double-fed asynchronous motor-generators design open slots capacity demand rotor converter air-gap length AGL conductive rotor slot wedges magnetic rotor slot wedges design method magnetic slot wedges mechanical analysis DFAMG prototype metal rotor wedges magnetic wedges two-dimensional field-circuit coupled model wedge configurations prototype performance DFAMG design design improvement

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Adaptivity of a B-spline based finite-element method for modeling wind-driven ocean circulation

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COMPUTER methodS IN APPLIED MECHANICS AND ENGINEERING 2018年 332卷 1-24页

作者： Al Balushi, Ibrahim Jiang, Wen Tsogtgerel, Gantumur Kim, Tae-Yeon McGill Univ Dept Math & Stat Montreal PQ H3A 2K6 Canada Idaho Natl Lab Fuels Modeling & Simulat Idaho Falls ID 83415 USA Khalifa Univ Sci & Technol Civil Infrastruct & Environm Engn Abu Dhabi 127788 U Arab Emirates

This paper presents an adaptive refinement algorithm of a B-spline based finite-element approximation of the streamfunction formulation for the large scale wind-driven ocean currents. In particular, we focus on a posteriori error analysis of the simplified linear model of the stationary quasi-geostrophic equations, namely the Stommel-Munk model, which is the fourth-order partial differential equation. The analysis provides a posteriori error estimator for the local refinement of the Nitsche-type finite-element formulation. Numerical experiments with several benchmark examples are performed to test the capability of the posteriori error indicator on rectangular and L-shape geometries. (C) 2017 Elsevier B.V. All rights reserved.

关键词： Adaptivity B-splines Nitsche's method Large-scale ocean circulation finite-element method

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Calculation of the loading capacity of high voltage cables laid in close proximity to heat pipelines using iterative finite-element method

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INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS 2018年 103卷 310-316页

作者： Nahman, Jovan Tanaskovic, Miladin Univ Belgrade Fac Elect Engn Bul K Aleksandra 73 Belgrade 11000 Serbia Elect Board Serbia Masarikova 1-3 Belgrade 11000 Serbia

The paper presents a new iterative finite-element model for the analysis of the thermal interference between a three-phase system of high voltage cables and heat pipelines buried in close proximity. A triangular formation of 110 kV cables and a pair of polyurethane insulated steel heat pipes are considered as a characteristic real-life example in authors' country. The maximum allowable load magnitudes for cables in winter weekdays have been determined for various distances between cables and pipes. The proposed mathematical model takes into account the effects of conduction, and the heat exchange by convection and radiation on the pavement surface. In order to adequately model the convective heat transfer from the water in motion an iterative approach is elaborated based upon the properties of the Nusselt number. It was shown that the maximum allowable magnitudes of load current of cables should be decreased for app. 6% if the distance between the cables and the adjacent pipe is 3 m, which is the minimum distance usually tolerated in practice in authors' country.

关键词： finite-element method Heat pipelines High voltage cables Loading capacity

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