• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.1664-1666
• /
• 2004

This paper describes the use of Armaid papers and varnishes in electric motors. We compare with boundary element method(BEM) and finite element method(FEM) by calculated electric field strength. Several computer software package to perform such calculations based on electrostatic field and applicable DC are available.

• Structural Engineering and Mechanics
• /
• v.22 no.1
• /
• pp.1-16
• /
• 2006

This paper presents a virtual boundary element-equivalent collocation method (VBEM) for the plane magnetoelectroelastic solids, which is based on the fundamental solutions of the plane magnetoelectroelastic solids and the basic idea of the virtual boundary element method for elasticity. Besides all the advantages of the conventional boundary element method (BEM) over domain discretization methods, this method avoids the computation of singular integral on the boundary by introducing the virtual boundary. In the end, several numerical examples are performed to demonstrate the performance of this method, and the results show that they agree well with the exact solutions. So the method is one of the efficient numerical methods used to analyze megnatoelectroelastic solids.

• Structural Engineering and Mechanics
• /
• v.20 no.2
• /
• pp.225-239
• /
• 2005

Applications of the Trefftz boundary element method (BEM) to anti-plane electroelastic problems are presented in this paper. Both direct and indirect methods with domain decomposition are discussed in details. Each crack is treated as semi-infinite thin slit defined in a subregion, for which a particular solution of the anti-plane problem, satisfying exactly the crack-face condition, is derived. The stress intensity factors defined at each crack tip can be directly computed from the coefficients of the particular solution. The performance of the proposed formulation is assessed by two examples and comparison is made with results obtained by other approaches. The Trefftz boundary element approach is demonstrated to be suitable for the analysis of the anti-plane problem of piezoelectric materials.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.13 no.11
• /
• pp.831-837
• /
• 2003

This paper investigates the insertion loss of nosie barrier with a interference device, The efficiency of the conventional interference-type noise barrier depends on specific frequency, Thus this study is performed to improve the efficiency of the nosie barrierin the range of broadband frequency. by changing the shape of interference device and adding the channel with various depths, The boundary element method (BEM) is used to predict the insertion loss of noise barrier. Two-dimensional boundary element model is created to simulate the performance of long barrier with a line source.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11b
• /
• pp.749-754
• /
• 2002

This paper investigates the insertion loss of nosie barrier with a interference device. The efficiency of the conventional interference-type noise barrier depends on specific frequency. Thus this study is performed to improve the efficiency of the nosie barrier in the range of broadband frequency, by changing the shape of interference device and adding the channel with various depths. The boundary element method (BEM) is used to predict the insertion loss of noise barrier. Two-dimensional boundary element model is created to simulate the performance of long barrier with a line source.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.7
• /
• pp.171-176
• /
• 2003

In this study, stress analysis using Boundary Element Method (BEM) was carried to investigate stress distribution in the brazing joint between a Hardmetal and a HSS. The two models were proposed to analyze the stress singularity in the interfaces of the brazing joint. The material type, thickness of the filler metal and the length of the vertical brazing adhesive are considered in the BEM analysis. As results, the peak point of the stress is founded to be in the lower interface of the brazed joint. It should be noted that the maximum stress of the peak point is being affected by the thickness and length of the brazing joint.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.8 no.1
• /
• pp.22-37
• /
• 2016

This article investigates numerical modeling of surface piercing propeller (SPP) in unsteady open water condition using boundary element method. The home code based on BEM has been developed for the prediction of propeller performance, unsteady ventilation pattern and cross flow effect on partially submerged propellers. To achieve accurate results and correct behavior extraction of the ventilation zone, finely mesh has generated around the propeller and especially in the situation intersection of propeller with the free surface. Hydrodynamic coefficients and ventilation pattern on key blade of SPP are calculated in the different advance coefficients. The values obtained from this numerical simulation are plotted and the results are compared with experiments data and ventilation observations. The predicted ventilated open water performances of the SPP as well as ventilation pattern are in good agreement with experimental data. Finally, the results of the BEM code/experiment comparisons are discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.769-772
• /
• 1997

In this study, By employing two dimensional(2-D) Boundary Element Method(BEM) stress analysis was carried to investigate stress distributions on the brazing joint of a Hardmetal and a HSS. Two model was proposed to analyze stress singularity in brazed interface. The stress results from the BEM were considered influence of the kind of materials , thickness of filled metal and length of vertical brazing adhesive. From those obtained results , the peak point of stress was founded in the lower part of two interface was made by brazing. As the thickness and length changed, the maximum stress tended to change in the peak point.

• The Journal of the Acoustical Society of Korea
• /
• v.24 no.3E
• /
• pp.115-122
• /
• 2005

Two twin microphones may produce particular patterns of binaural directivity by time delays between twin microphones. The boundary element method (BEM) was used for the simulation of the sound pressure field around the head model in order to quantify the acoustic head effect. The sound pressure onto the microphone was calculated by the BEM to an incident sound pressure. Then a planar directivity pattern was formed by four sound pressure signals from four microphones. The optimal binaural directivity pattern may be achieved by adjusting time delays at each frequency while maintaining the forward beam pattern is relatively bigger than the backward beam pattern.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.5
• /
• pp.883-890
• /
• 1992

Analysis of dynamic or impact problems is very important in engineering fields such as airplanes and automobiles. In the present study, two-dimensional elastodynamic BEM program with Laplace transformation is developed to analyze dynamic or impact problems. Accuracy and efficiency of the BEM program are tested by making the comparision of impact analysis of some models with other's published results. The BEM developed is applied to the impact crack problem and the dynamic stress intensity factors of some impact cracks is obtained by the displacement extrapolation method. It is confirmed to be possible to analyze impact problems accurately with only a little elements in simple models. And also it is found to be careful to use the singular element usually using in static crack problems because that the elastodynamic fundamental solution usually using in static crack problems because that the elastodynamic fundamental solution has more sensitive singularity than the static fundamental solution and to determine the boundary conditions in dynamic problems.