Asymptotic boundary conditions for open boundaries of axisymmetric magnetostatic finite-element models

2002 ◽  
Vol 38 (2) ◽  
pp. 469-472 ◽  
Author(s):  
S. Gratkowski ◽  
L. Pichon ◽  
H. Gajan
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Finite Element Models ◽  
Asymptotic Boundary ◽  
Open Boundaries

Asymptotic boundary conditions for axisymmetric finite element electrostatic analysis

1994 ◽  
Vol 30 (6) ◽  
pp. 4335-4337 ◽  
Author(s):  
Qiushi Chen ◽  
A. Konrad ◽  
S. Baronijan
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Asymptotic Boundary

scholarly journals Asymptotic boundary conditions for the analysis of hydrodynamic stability of flows in regions with open boundaries

2019 ◽  
Vol 34 (1) ◽  
pp. 15-29 ◽  
Author(s):  
Andrey V. Boiko ◽  
Kirill V. Demyanko ◽  
Yuri M. Nechepurenko
Keyword(s):  
Boundary Conditions ◽  
Hydrodynamic Stability ◽  
Constant Velocity ◽  
Eigenvalue Problems ◽  
Main Flow ◽  
New Approach ◽  
Asymptotic Boundary ◽  
Open Boundaries ◽  
Temporal And Spatial ◽  
Parallel Approximation

Abstract A new approach to formulation of asymptotic boundary conditions for eigenvalue problems arising in numerical analysis of hydrodynamic stability of such shear flows as boundary layers, separations, jets, wakes, characterized by almost constant velocity of the main flow outside the shear layer or layers is proposed and justified. This approach makes it possible to formulate and solve completely the temporal and spatial stability problems in the locally-parallel approximation, reducing them to ordinary algebraic eigenvalue problems.

Analysis of Collisions of Vehicle and Concrete Barrier on Rural Highways

2011 ◽  
Vol 415-417 ◽  
pp. 2304-2307
Author(s):  
Yu Juan Sun ◽  
Jian Rong ◽  
Yong Gang Tai
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Road Safety ◽  
Finite Element Models ◽  
Collision Process ◽  
Rural Highways ◽  
The Road ◽  
Safety Barrier ◽  
Nonlinear Performance ◽  
Concrete Barrier

A concrete barrier used on rural highways of China was proposed. The crashworthiness of the concrete barrier was analyzed using the non-linear explicit dynamics FE code LS-DYNA. The finite element models of car, bus and concrete barrier were developed and validated using experimental results. These models can be used to simulate the dynamic collision process and evaluate the performance of the road safety barrier on rural highways. The nonlinear performance of materials as well as the boundary conditions was considered. The results show that the concrete barrier could contain and redirect the car and bus in the collision.

Finite Element Analysis in 3D Using the Penalty Boundary Method

2002 ◽  
Author(s):  
Brett W. Clark ◽  
David C. Anderson
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Boundary Conditions ◽  
Mesh Generation ◽  
Discretization Error ◽  
Finite Element Models ◽  
Element Analysis ◽  
Hexahedral Elements ◽  
Boundary Method ◽  
Time Required

Traditional methods for applying boundary conditions in finite element analysis require the mesh to conform to the geometry boundaries. This in turn requires complex meshing algorithms for automated mesh generation from CAD geometry, particularly when using quadrilateral and hexahedral elements. The 3D extension of the penalty boundary method (PBM) is presented as a method that significantly reduces the time required generating finite element models because the mesh is not required to conform to the CAD geometry. The PBM employs penalty methods to apply boundary conditions on a simple, regular mesh. The PBM also eliminates discretization error because boundary conditions are applied using CAD geometry directly rather than an approximation of the geometry.

Vibro-Acoustic Studies of Transmission Casing Structures

1998 ◽  
Author(s):  
D. Crimaldi ◽  
R. Singh
Keyword(s):  
Finite Element ◽  
Free Boundary ◽  
Boundary Conditions ◽  
Material Properties ◽  
Acoustic Radiation ◽  
Real Life ◽  
Cover Plate ◽  
Mode Shapes ◽  
Finite Element Models ◽  
Free Boundary Conditions

Abstract Automotive transmission casing plates of irregular shape, with complex boundary conditions and non-uniform material properties, are experimentally and computationally studied to acquire a fundamental understanding of their dynamic and acoustic radiation characteristics. A modified flat cover is designed which simplifies the geometry while providing uniform thickness and material properties. Both covers (“real-life” and “laboratory”) are studied with free and bolted boundary conditions. In particular, the free boundary conditions are useful because they eliminate the cover-housing interaction allowing for a more detailed analysis of the cover plate. Finite element models for both covers under the free boundary conditions are developed and refined. Predicted natural frequencies and mode shapes are in excellent agreement with measured modal data. Then the finite element models are coupled with boundary element models to predict acoustic radiation properties. Predictions match well with measured acoustic directivity at resonant frequencies.

scholarly journals Feasibility Study on Tension Estimation Technique for Hanger Cables Using the FE Model-Based System Identification Method

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Kyu-Sik Park ◽  
Taek-Ryong Seong ◽  
Myung-Hyun Noh
Keyword(s):  
Finite Element ◽  
System Identification ◽  
Boundary Conditions ◽  
Natural Frequency ◽  
Inverse Analysis ◽  
Finite Element Models ◽  
Fe Model ◽  
Identification Methods ◽  
System Identification Method ◽  
Model Based

Hanger cables in suspension bridges are partly constrained by horizontal clamps. So, existing tension estimation methods based on a single cable model are prone to higher errors as the cable gets shorter, making it more sensitive to flexural rigidity. Therefore, inverse analysis and system identification methods based on finite element models are suggested recently. In this paper, the applicability of system identification methods is investigated using the hanger cables of Gwang-An bridge. The test results show that the inverse analysis and systemic identification methods based on finite element models are more reliable than the existing string theory and linear regression method for calculating the tension in terms of natural frequency errors. However, the estimation error of tension can be varied according to the accuracy of finite element model in model based methods. In particular, the boundary conditions affect the results more profoundly when the cable gets shorter. Therefore, it is important to identify the boundary conditions through experiment if it is possible. The FE model-based tension estimation method using system identification method can take various boundary conditions into account. Also, since it is not sensitive to the number of natural frequency inputs, the availability of this system is high.

scholarly journals Assessment of Model Uncertainty in the Prediction of the Vibroacoustic Behavior of a Rectangular Plate by Means of Bayesian Inference

2021 ◽  
pp. 264-277
Author(s):  
Nikolai Kleinfeller ◽  
Christopher M. Gehb ◽  
Maximilian Schaeffner ◽  
Christian Adams ◽  
Tobias Melz
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Bayesian Inference ◽  
Boundary Conditions ◽  
Model Uncertainty ◽  
Prediction Error ◽  
Finite Element Models ◽  
Simply Supported ◽  
Thin Walled Structures ◽  
Thin Walled

AbstractDesigning the vibroacoustic properties of thin-walled structures is of particularly high practical relevance in the design of vehicle structures. The vibroacoustic properties of thin-walled structures, e.g., vehicle bodies, are usually designed using finite element models. Additional development effort, e.g., experimental tests, arises if the quality of the model predictions are limited due to inherent model uncertainty. Model uncertainty of finite element models usually occurs in the modeling process due to simplifications of the geometry or boundary conditions. The latter highly affect the vibroacoustic properties of a thin-walled structure. The stiffness of the boundary condition is often assumed to be infinite or zero in the finite element model, which can lead to a discrepancy between the measured and the calculated vibroacoustic behavior. This paper compares two different boundary condition assumptions for the finite element (FE) model of a simply supported rectangular plate in their capability to predict the vibroacoustic behavior. The two different boundary conditions are of increasing complexity in assuming the stiffness. In a first step, a probabilistic model parameter calibration via Bayesian inference for the boundary conditions related parameters for the two FE models is performed. For this purpose, a test stand for simply supported rectangular plates is set up and the experimental data is obtained by measuring the vibrations of the test specimen by means of scanning laser Doppler vibrometry. In a second step, the model uncertainty of the two finite element models is identified. For this purpose, the prediction error of the vibroacoustic behavior is calculated. The prediction error describes the discrepancy between the experimental and the numerical data. Based on the distribution of the prediction error, which is determined from the results of the probabilistic model calibration, the model uncertainty is assessed and the model, which most adequately predicts the vibroacoustic behavior, is identified.

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