• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.52 no.3
• /
• pp.93-100
• /
• 2003

Switched reluctance motor(SRM) has some advantages such as low cost, high torque density but SRM has essentially high torque ripple due to its salient structure. In order to apply SRM to industrial field, torque ripple has to be reduced. This paper introduces optimal design process of SRM using an optimization algorithm of Progressive Quadratic Response Surface Modeling(PQRSM) and two-dimensional(2D) Finite Element Method(FEM). The electrical and geometrical design parameters have been adopted as 2D design variables. From this work, it can be obtained both the optimal design minimized torque ripple and the optima1 design maximized the average torque, respectively. Finally, this Paper Presents Performance comparison of two optimal designs and consider influence of the selected design variables in torque characteristics.

• Journal of KSNVE
• /
• v.9 no.3
• /
• pp.565-569
• /
• 1999

Recently, fiber optic hydrophone is a subject which has attracted as a underwater acoustic sensor. In this study, Finite element modeling of fiber optic hydrophone for hollow cylindrical mandrel was performed and the acoustic sensitivity was calculated to estimate the performance of single element fiber optic hydrophone. And acoustic sensitivity was measured in acoustic water tank to verify the result of simulation. The result of FE analysis and experiment is -126 dB re rad/$\mu$ Pa and -128 dB re rad/$\mu$ Pa respectively.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.1
• /
• pp.49-56
• /
• 2009

This paper shows the characteristic analysis of single-phase line start permanent magnet (LSPM) motors considering the overhang structure. To achieve the low-cost design of an LSPM motor, the overhang structure is adapted for the rotor with a constraint of a fixed magnet volume. To obtain the dynamic and steady performance of the motor, the circuit parameters are extracted using the 3D-static FEM(Finite Element Method) and the d-q equivalent circuit is used. The performance of the model with overhang is compared with the conventional model without overhang on the condition that both models have a fixed volume for the permanent magnet.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.285-290
• /
• 2005

Micro On-Off valves are currently recognized as the core technology in the fields of the micro fluid chip fur medical applications and production lines of semi-conduct chip. Micro valves that operate by compressed air need the high-speed responsibility, repeatability, the absorbability and the uniform pressure by the poppet. In this study, Micro On-Off valves that posses the high-speed responsibility and the high rate of flow have designed and analyzed through the law of equivalent magnetic circuit and Finite Element Method (FEM) respectively. In case of poppet, Flow field characteristic was analyzed by the variation of poppet and it was able to display flow field by changing the location of the poppet. Also, we verified possibility of the design through the static and dynamic pressure and the 3D distribution curve of the force by working the front poppet.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.20 no.5
• /
• pp.351-356
• /
• 2008

In this study, we had the stress analyses of TBP used in Tall Building and determined the working pressure of TBP. We knew the four fact. First, the place acted maximum stress is axial direction of branched part. Second, working pressure is more than 2.0 MPa. Third, stress in branched part is less than yielding strength at hydrostatic test pressure. Fourth, the ratio(stress/yielding stress at hydrostatic test pressure) is $0.4{\sim}0.6$(KS D 3562 Sch 40), $0.3{\sim}0.4$(KS D 3576 20S).

• Geomechanics and Engineering
• /
• v.32 no.4
• /
• pp.397-409
• /
• 2023

This study examines two traditional approaches (non-linear elastic and elasto-plastic) in association with 2D and 3D FEM analyses of a box-section pile embedded in sand. A particular emphasis is placed on stress singularities concerning both reentrant corners of the pile section and the resulting tension zones. From the experience gained in this study, non-linear elastic soil models are less restrictive when one considers stress singularities and their possible effects on convergence of the solution. At least for monotonic loading, when compared with field tests, non-linear elastic models yield better results than the plasticity ones. On the other hand, although elasto-plastic models are not limited to monotonic loading, they are much more sensitive to stress singularities. For this reason, a spherical elastic region is necessary at the pile tip to ensure convergence. Without this region, one must artificially impose an apparent cohesion to limit the tension stresses within a sand medium.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.3
• /
• pp.349-357
• /
• 2014

The performance of a Synchronous Reluctance Motor (SynRM) in terms of torque and power factor depends on the two-axis inductances $L_d$ and $L_q$ of the machine. The Axially Laminated Anisotropic (ALA) rotor should be proposed in an effort to increase the $L_d/L_q$ ratio and the $L_d-L_q$ difference to secure high torque density and high power factor. So, ALA rotor is suitable for high speed instruments. This paper deals with optimum design of Axially Laminated Anisotropic Synchronous Reluctance Motor (ALA-SynRM) and comparison of characteristics with induction motor. Coupled Finite Element Methodology (FEM) & Response Surface Methodology (RSM) have been used to evaluate optimum design solutions. Comparisons are given with characteristics of a same rated wattage induction motor and those of ALA-SynRM respectively.

• Advances in aircraft and spacecraft science
• /
• v.10 no.2
• /
• pp.127-140
• /
• 2023

The present article focuses on the thermoelastic deformation behavior of inhomogeneous functionally graded metal/ceramic cylindrical shell structure with multiple perforations using 2D finite element approximation. Here, cylindrical shell structure is considered with single (1×1) and multiple (2×2, 3×3 and 4×4) perforations. The temperature-dependent elastic and thermal properties of functionally graded material are evaluated using Voigt's micromechanical material scheme via power-law function. The kinematics of the proposed model is based on the equivalent single-layer first-order shear deformation mid-plane theory with five degrees-of-freedom. Here, 2D isoparametric finite element solutions are obtained using eight-node quadrilateral elements. The mesh refinement of present finite element model is performed to confirm the appropriate number of elements and nodes for the analysis purpose. Subsequently, a comparison test is conducted to demonstrate the accuracy of present results. In later section, numerous numerical illustrations are demonstrated at different set of conditions by varying structural, material and loading parameters and that confirms the significance of various parameters such as power-law index, aspect ratio, thickness ratio, curvature ratio, number of perforations and temperature on the deformation characteristics of functionally graded cylindrical shell structure.

• Journal of the Korean Magnetics Society
• /
• v.22 no.2
• /
• pp.49-57
• /
• 2012

From among the NDT (Non-Destructive Testing) methods, the MFL (Magnetic Flux Leakage) PIG (Pipeline Inspection Gauge) is especially suitable for testing pipelines because the pipeline has high magnetic permeability. MFL PIG showed high performance in detecting the metal loss and corrosions. However, MFL PIG is difficult to detect the crack which occured by exterior-interior pressure difference in pipelines and the shape of crack is very long and narrow. Therefore, the new PIG is needed to be researched and developed for detecting the cracks. The CMFL (Circumferential MF) PIG performs magnetic fields circumferentially and can maximize the magnetic flux leakage at the cracks. In this paper, CMFL PIG is designed and the distribution of the magnetic fields is analyzed by using 3 dimensional nonlinear finite element method (FEM). By Simulating and Measuring the magnetic leakage field, it is possible to detect of axial cracks in the pipeline.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.32 no.3
• /
• pp.58-65
• /
• 2004

Thermal and structural finite element analyses were performed for the turbopump turbine bladed disk model with shroud of a liquid rocket engine. The only 1/80 part model was analyzed which consists of 3D eight node isoparametric solid elements. The applied loading history consists of a startup condition with a thermal spike and a steady state. Heat transfer coefficient on the blade was predicted using the commercial Navier-Stokes solver, Fluent. Transient thermal responses during startup and steady states were calculated using a 3D finite element code developed. Maximum stress and shroud tip displacement under the influence of centrifugal and thermal loading were also determined.