• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.973-978
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• 2007

In this paper, we make a study of a thermal deformation by FEM and test to define the deformation mode of the Vacuum-Cleaner's Nozzle-Cover. In FEM analysis, 3 different conditions were considered separately, such as (1) Compressive force by Belt tension, (2) Friction heat between Belt and Shaft and (3) Compressive force combined with heat. Throughout FEM analysis it was found that the deformation was caused by heat and it was proved through a simulation test with a real product.

• Journal of the Korean Society for Railway
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• v.12 no.3
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• pp.437-442
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• 2009

In the case of a Linear Induction Motor (LIM), numerical analysis method like Finite Element Method (FEM) has been mainly used to analyze the travelling magnetic field problem which includes the velocity-induced electromotive force. If the problem including the velocity-induced electromotive force is analyzed by FEM using the Galerkin method, the solution can be oscillated according to the Peclet Number, which is determined by conductivity, permeability, moving velocity and size of mesh. Consequently, the accuracy of the solution can be low and the vortexes of flux can be occurred at the secondary back-iron. These vortexes of the flux occurred at the secondary back-iron does not exist physically, but it can be occurred in the analysis. In this case, the vortexes of the flux can be generally removed by using Up-Wind method which is impossible to apply a conventional S/W tool (Maxwell 2D). Therefore, in this paper, authors examined the vortexes of the flux occurred at the secondary back-iron of the LIM according to variations of the Peclet Number, and analyzed whether these vortexes of the flux affect on the dynamic force characteristics of the LIM or not.

• Transactions of Materials Processing
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• v.17 no.2
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• pp.124-129
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• 2008

Net shape forging technologies give many effects into the costs and qualities for the finished products. So, the studies to reduce the additional machining amount are very important in forging industry. Specially, there are two main topics in cold forging industry, such as, tool life and precision forging. In this study, new forging technique was proposed to eliminate the machining process for fixing up the length and improve the lead accuracy of gear. The luck-up hub is manufactured through many processes, such as upsetting, piercing and direct extrusion. The gear is formed in direct extrusion process; however, lead accuracy of the gear is over allowance limit. Therefore, the additional sizing process must be added. In this study, process design for closed-die forging of a lock-up hub used for a component of automobile transmission was made using three-dimensional finite element simulations, and the strain distributions and velocity distributions are investigated through the post processor. The rigid-plastic finite-element method for back pressure forging has been used in order to reduce development time and die cost. Using the FEM simulation, we found the optimum value of back pressure. The prototypes of lock-up hub parts were forged into the net-shape. In the experiment, lead precision of tooth are measured by the CCMM(Contact Coordinate Measuring Machine). The dimensional accuracy of forged part was improved up to the 40% when back press was applied.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.4
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• pp.258-264
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• 2015

The first 77 GHz transceiver that applies a heterodyne structure-based linear frequency modulation-frequency shift keying (LFM-FSK) front-end module (FEM) is presented. An LFM-FSK waveform generator is proposed for the transceiver design to avoid ghost target detection in a multi-target environment. This FEM consists of three parts: a frequency synthesizer, a 77 GHz up/down converter, and a baseband block. The purpose of the FEM is to make an appropriate beat frequency, which will be the key to solving problems in the digital signal processor (DSP). This paper mainly focuses on the most challenging tasks, including generating and conveying the correct transmission waveform in the 77 GHz frequency band to the DSP. A synthesizer test confirmed that the developed module for the signal generator of the LFM-FSK can produce an adequate transmission signal. Additionally, a loop back test confirmed that the output frequency of this module works well. This development will contribute to future progress in integrating a radar module for multi-target detection. By using the LFM-FSK waveform method, this radar transceiver is expected to provide multi-target detection, in contrast to the existing method.

• Computers and Concrete
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• v.29 no.3
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• pp.161-168
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• 2022

Bridges using double-tee (DT) girders from 12 m to 15 m are one of the good choices to improve accessibility in rural areas of the Mekong River Delta. In this study, nonlinear finite element method (FEM) analysis was conducted with different constitutive laws of materials. The FEM analysis results were compared to experimental results to confirm the applicability of the constitutive laws of materials for DT girders. A parametric study through FEM analysis was then conducted to investigate the effect of span lengths, top flange depths, and a number of prestressing tendons on the capacity of DT girders in order that propose DT girders for rural bridges. Parametric results showed that the top flange depth of a DT girder for rural bridges could be 120 mm. The DT girder with a span length of 12 m or 13 m could be used 16 tendons, while the DT girder with a span length of 14 m or 15 m could be set up with 20 tendons. The prestressed concrete DT girders based on FEM results can be suggested for the construction of rural bridges.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.4
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• pp.38-51
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• 2007

This paper describes research results for the measurement and analysis method of magnetic signatures generated from the ship's magnetic mock-up model. In this paper, we present the theoretical and experimental techniques for the separation of the permanent and the induced magnetic field from the measured magnetic signature of the mock-up model. Also, we describe the prediction method of the induced magnetic field generated from mock-up model using the Magnet s/w, one of the FEM analysis tools for the electro-magnetic field and the magnetic dipole modelling method based on the least square techniques. The proposed modelling and analysis methods can be used for the prediction and the analysis of the static magnetic field generated from the real naval ship as well as the mock-up model.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.58-64
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• 2016

In this paper, the design of rotor shape was performed for improvement of start-up characteristics and efficiency in single-phase LSPM. In order to improve the start-up characteristics, shape of rotor aluminium cage bar was changed. Through arrangement of permanent magnets and installation of flux barriers, it was performed torque ripple reduction and efficiency improvement. Cogging torque and back-EMF is calculated by the no-load analysis, start-up time is calculated by the start-up state analysis, efficiency and torque ripple is calculated by steady state analysis. The characteristics of the motor were calculated through FEM.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.252-255
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• 2009

The roll gap set-up in the finishing mill is one of the most important technologies in the hot plate rolling process. As the target thickness can be obtained by the correct set-up of the roll gap, improving the roll gap set-up technology is very critical for plate thickness accuracy. The main cause of thickness variation in hot plate mills is the non-uniform temperature distribution along the length of the slab. The objective of this study is to adjust the roll gap set-up for the thickness accuracy of plate in hot rolling process considering top-end temperature drop. Therefore this study has concentrated on determining the correct amounts of roll gap to compensate thickness variation due to top-end temperature drop. The off-line simulation of compensated roil gap significantly decreases top-end thickness variation.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.3_4 s.141
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• pp.414-424
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• 2005

This study aims to suggest new directions for the development of make-up design by understanding characteristics of deconstruction make-up and to search for new directions and methods in theme expressions and design conceptions by making illustrations with deconstruction themes. This study examines conceptual characteristics of Derrida's deconstruction, and analyzes the various deconstruction make-up styles through the famous fashion magazines such as Beauty Collection, Collections, Fem, Modain, and Vogue since 1997. The make-up illustration works in this study were made depending on these styles. At first, the nature of deconsouction make-up can be explained as deconstruction of existing methods, deconstruction of the sexes and deconstruction of history or ethnicity. The deconstruction of existing methods can be subdivided into decadence make-up, detester make-up, graphic make-up and collage make-up. Deconstruction of the sexes can be explained androgynous make-up. Deconstruction of history or ethnicity is subdivided into white makeup, ancient Egyptian dark eye make-up and raceless make-up. The deconstruction make-up illustrations present infinite possibilities in expression styles through three dimensional expressions and media mixture using not only drawing materials including watercolor, poster-color, and color pencils but also objets including magazines, coarse fabrics, screentone, beads, suede, sand and so on. The study shows that since deconstruction make-up illustrations are not limited to depiction-centered expressions, they serve creating unique images and future inspirations.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2006.09a
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• pp.17-20
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• 2006