• Journal of Magnetics
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• v.18 no.2
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• pp.130-134
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• 2013

Most electrical machines like motor, generator and transformer are symmetric in terms of magnetic field distribution and mechanical structure. In order to analyze these problems effectively, many coupling techniques have been introduced. This paper deals with a coupling scheme for open boundary problem of symmetric and periodic structure. It couples an analytical solution of Fourier series expansion with the standard finite element method. The analytical solution is derived for the magnetic field in the outside of the boundary, and the finite element method is for the magnetic field in the inside with source current and magnetic materials. The main advantage of the proposed method is that it retains sparsity and symmetry of system matrix like the standard FEM and it can also be easily applied to symmetric and periodic problems. Also, unknowns of finite elements at the boundary are coupled with Fourier series coefficients. The boundary conditions are used to derive a coupled system equation expressed in matrix form. The proposed algorithm is validated using a test model of a bush bar for the power supply. And the each result is compared with analytical solution respectively.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.3
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• pp.413-420
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• 2020

The Tactical Information and Communication Network system provides real-time multimedia services such as voice and data by utilizing the Mobile Subscriber Access Point. At this time, an external transmission path is constructed through the Low Capacity Trunk Radio and the High Capacity Trunk Radio system. The communication devices of each wireless transmission system are mounted on a tactical vehicle and a secondary battery is used to prevent a power interruption when the supply power to the tactical vehicle is transferred to the integrated power control device. In this paper, the basic design of the Wireless Power Transfer device for charging the battery of the integrated power control system of the mobile base station system using the Loading Distribution Method and checking the number of primary windings and the core material selection by the air gap through the Finite Elements Method.

• Design & Manufacturing
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• v.14 no.3
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• pp.57-62
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• 2020

In the drug delivery system industry, the technology with even split injection becomes important for maximizing efficiency and minimizing the side effects. In conventional drug delivery system, infection can occur due to pain and splashing. Also, various applications are impossible due to disposable use, and it is the reason to avoid to use this system because of the complexity of the driving method. Therefore, in this study, a painless drug delivery device is developed for non-pain with electrical insulation breakdown method. Finite elements analysis was used to evaluate the ejection characteristics of drugs according to the shape of the micro ejection nozzle. The effect of the number of holes in the micro nozzle, the length of the nozzle and the inner shape of the nozzle on the drug discharge characteristics were analyzed.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.5
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• pp.61-68
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• 2004

Methodologies of the finite element and boundary element are combined to achieve an efficient and accurate analysis model of frame structure containing shear wall. This model analyzes the frame by employing the finite element method and the shear wall by boundary element method. This study is applicable to a specific situation, where the boundary element is surrounded by finite elements. By employing FE dominant method in which boundary stiffness matrix is transformed into finite element stiffness matrix, boundary element and finite element method are combined to analyze frame structure with walls.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.78-84
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• 2008

This paper presents a fast modeling technique of virtual pottery using force feedback based on a circular sector element method. Previous techniques for simulating deformable objects such as finite element method (FEM) are limited in real-time haptic rendering due to their complexity and expensive computational cost. In our model, circular sector elements which fully represent features of pottery's shape are closely gathered and piled together. This allows efficient deformable object modeling through a decrease in the number of elements and reducing computational cost.

• Proceedings of the Korean Society of Laser Processing Conference
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• 1999.05a
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• pp.29-32
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• 1999

The material properties of laser welding zone such as strength coefficient, work-hardening exponent, and plastic anisotropic ratio are analytically obtained from those of base metals based on the tensile tests. . The finite element formulation is developed for predicting strain distributions and weld line movements in the forming processes of laser welded blank. The welding zone(WZ) is modelled with the several, narrow finite elements whose material characteristics are based on the experimental results and the analytical equations. In order to show an application of the developed weld element the stamping process of auto-body door inner panel is simulated. FEM predictions are compared and showed good agreements with experimental observations.

• Journal of the Semiconductor & Display Technology
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• v.10 no.3
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• pp.61-65
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• 2011

The capabilities of finite elements codes allow now accurate simulations of blanking processes when appropriate materials modelling are used. Over the last decade, numerous numerical studies have focused on the influence of process parameters such as punch-die clearance, tools geometry and friction on blanking force and blank profile. In this study, three dimensional finite element analysis is carried out to design a lead frame blanking die using LS-Dyna3D package. After design of the blanking die, an experiment is also carried out to investigate the characteristics of blanking for nickel alloy Alloy42, a kind of IC lead frame material. In this paper, it has been researched the investigation to examine the influence of process parameters such as clearance and air cylinder pressure on the accuracy of sheared plane. Through the experiment results, it is shown that the quality of sheared plane is less affected by clearance and air cylinder pressure.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.03a
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• pp.36-39
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• 1998

To predict strain distributions and weld line movements in the forming processes of tailored blank sheets, the 2-dimensional finite element formulation is developed. The welding zone is modelled with the several, narrow finite elements. The material properties of weld elements are calculated from those of base metals, based on the experimental evaluation. To verify the finite element formulation developed, the forming process of an autobody door inner panel section is simulated. FEM predictions are compared and showed good agreements with experimental measurements.

• Structural Engineering and Mechanics
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• v.48 no.1
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• pp.125-150
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• 2013

This paper intends to present an application of isogeometric analysis in crack problems. An isogeometric formula is developed based on NURBS basis functions - enriched and adopted via X-FEM enrichment functions. The proposed method which is represented by the combination of the two above-mentioned methods, first by using NURBS functions models the geometry exactly and then by defining level set function on domain, identifies available discontinuity in elements. Additional DOFs are allocated to elements containing the crack and X-FEM enrichment functions enrich approximate solution. Moreover, a subelement refinement technique is used to improve the accuracy of integration by the Gauss quadrature rule. Finally, several numerical examples are illustrated to demonstrate the effectiveness, robustness and accuracy of the proposed method during calculation of crack parameters.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.9
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• pp.1091-1097
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• 2011

The SGBEM-FEM alternating method has been known to be a very effective method for analyzing threedimensional cracks in a finite body. The accurate values of the stress intensity factor can be obtained for a general planar or nonplanar three-dimensional crack. In the existing method, eight-noded quadrilateral boundary elements are used to model a crack. In some cases, three-node triangle boundary elements are more convenient for the modeling of a crack with a general shape. In this study, a crack is modeled with three-noded triangular and seven-noded quadrilateral elements by using the advancing-front mesh generation method. The stress intensity factors are obtained for cracks with several shapes and the accuracy of results is examined.