• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.55-56
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• 2010

Infill walls have been investigated experimentally and theoretically by many researchers during last decades. The objective of this research is to evaluate structural strengthening performance of lightly reinforced concrete with reduced the inside cross-section of Strain-hardening cement composites(SHCC) experimentally.

• Journal of computational fluids engineering
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• v.19 no.1
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• pp.57-63
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• 2014

This study performed numerical analysis for the characteristics of flow-induced forces and the flow instability depending on the cross-sectional shape of the cylinder in laminar flow. To implement the cylinder cross-section, we adopted an Immersed Boundary Method with marker particles. We analyzed flow characteristics based on the radius of corner curvature. Main parameters are corner radius and Reynolds number (Re). With Re = 40, 50, 150 we calculated the flow field, drag coefficient, RMS of lift coefficient, pressure coefficient and Strouhal number in conjunction with the corner radius variation. Also, we calculated critical Reynolds number ($Re_c$) depending on the corner radius variation.

• Journal of the Korean Vacuum Society
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• v.8 no.1
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• pp.1-8
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• 1999

A boundary condition reflecting automatically, regardless of the direction of the gas flow, the pressure drop due to the entrance and exit effect occurred at a connection of two elements with different cross-sections in calculating the pressure profile of a vacuum network composed of many chambers and pipes which have different shape and vacuum properties was developed. The method of correcting the pressure drop in an element of varying cross-section like a cone was also introduced to keep the system free from directionality. The developed boundary conditions are applied as an example to a linear composed vacuum system to show how to make a set of simultaneous equations based on the particle balance equation and how to obtain its solution.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.1
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• pp.57-65
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• 1992

The main purpose of this paper is to present both the natural frequencies and mode shapes of tapered beams under tensile axial force. The differential equation governing planar free vibration for tapered beams under tensile axial force is derived as nondimensional form. The three kinds of cross sectional shape are considered in differential equation. The Runge-Kutta method and Determinant Search method are used to perform the integration of the differential equation and to determine the natural frequencies, respectively. The hinged-hinged, hinged-clamped, clamped-clamped and constraints are applied in numerical examples. The lowest four nondimensional natural frequencies are reported as the function of nondimensional tensile axial force. The fundamental natural frequencies are presented when section ratios and nondimensional axial forces are varied. The effects of cross sectional shapes are reported and some typical mode shapes are also presented.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.186-192
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• 2005

A numerical study on the performance of a PEMFC was performed by using a CFD-ACE+commercial program. The effects of width, hight and shape of channel cross section and mass flow rate were investigated. In order to check the validity of the simulation, comparisons were carried out between predictions and experimental data available in the literature and shows the reasonable agreement. It is found that only the width of channel is strongly related to the performance of a PEMFC, while other factors have no marked effects.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.93-100
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• 2001

The three dimensional(3D) reconstruction from two dimensional(2D) image data is using in many fields such as RPD(Rapid Product Development) and reverse engineering. In this paper, the main step of 3D reconstruction is comprised of two steps : image processing step and B-spline surface approximation step. In the image processing step, feature points of each cross-section are obtained by means of several image processing technologies. In the B-spline surface approximation step, using the data of feature points obtained in the image processing step, the control points of B-spline surface are obtained, which are used for IGES file of 3D CAD model.

• Structural Engineering and Mechanics
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• v.22 no.2
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• pp.131-150
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• 2006

Exact analytical solutions for in-plane static problems of planar curved beams with variable curvatures and variable cross-sections are derived by using the initial value method. The governing equations include the axial extension and shear deformation effects. The fundamental matrix required by the initial value method is obtained analytically. Then, the displacements, slopes and stress resultants are found analytically along the beam axis by using the fundamental matrix. The results are given in analytical forms. In order to show the advantages of the method, some examples are solved and the results are compared with the existing results in the literature. One of the advantages of the proposed method is that the high degree of statically indeterminacy adds no extra difficulty to the solution. For some examples, the deformed shape along the beam axis is determined and plotted and also the slope and stress resultants are given in tables.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.4
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• pp.79-85
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• 2006

Multi-filament hydrostatic extrusion was developed as a fine wire manufacturing process and wire forming experiments were conducted. Also, single wire stretch forming process was proposed in the possibility of obtaining long wire with constant cross-section. In the multi filament extrusion since the workpiece, die and forming facility are in the macro forming circumstance, fine wire and fine hole structure with less than a few micrometer can be easily obtained. Although stretch forming does not use a die in order to avoid the friction problem between the workpiece and the die, it is necessary to have high level of technology to maintain cross-sectional shape and measure in longitudinal direction.

• Structural Engineering and Mechanics
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• v.80 no.5
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• pp.625-643
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• 2021

In this paper, we present a new method to calculate interface warping functions for the analysis of beams with geometric and material discontinuities in the longitudinal direction. The classical Saint Venant torsion theory is extended to a three-dimensional domain by considering the longitudinal direction. The interface warping is calculated by considering both adjacent cross-sections of a given interface. We also propose a finite element procedure to simultaneously calculate the interface warping function and the corresponding twisting center. The calculated interface warping functions are employed in the continuum-mechanics based beam formulation to analyze arbitrary shape cross-section beams with longitudinal discontinuities. Compared to the previous work by Yoon and Lee (2014a), both geometric and material discontinuities are considered with fewer degrees of freedom and higher accuracy in beam finite element analysis. Through various numerical examples, the effectiveness of the proposed interface warping function is demonstrated.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.6
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• pp.96-104
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• 1995

A study for a lathe to machine workpiece with noncircular cross-section is presented. The noncircular cutting is accomplished by controlling radial tool position synchronized with revolution angle of the spindle according to the desired cross-sectional shape. A learning control algorithm is suggested for the tool positioning. The learning law of the algorithm is based on pole-zero cancellation, which guarantees the control stability. The control performances are analyzed and simulated on a numerical computer that the effectiveness of the control algorithm is convinced. The algorithm is tested on a conventional NC-lathe which shows some successful results.