• Computational Structural Engineering
• /
• v.11 no.4
• /
• pp.253-265
• /
• 1998

본 논문에서는 연계논문에서 제시한 비대칭 박벽단면을 갖는 곡선보 및 직선보 이론을 토대로, 곡선보 요소 및 직선보 요소를 개발하고 이를 이용한 유한요소 정식화 과정을 제시한다. 유한요소 정식화 과정에서는 요소의 변위장을 도심에 대하여 정의한 후, 요소 변위벡터에 관한 3차의 Hermitian 다항식을 형상함수로 사용하고 가우스 적분을 행함으로써 탄성 강도행렬 및 기하학적 강도행렬을 산정하였다. 얻어진 강도행렬을 이용하여 고유치 문제를 계산함으로써 좌굴하중을 계산하였으며 다양한 해석 예제를 통하여 다른 연구자들의 해석 결과와 비교 검토함으로써 본 연구의 타당성과 우수성을 입증하고자 한다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2007.10a
• /
• pp.230-233
• /
• 2007

Due to their low density, high specific strength and electromagnetic interference shielding, magnesium alloy sheets are used increasingly more often in automotive, aerospace, and electronics industries. However, magnesium ally sheets should be usually formed at elevated temperature because of their poor formability at room temperature. For the use of magnesium alloy sheets for an industrial, their mechanical properties at elevated temperature and appropriate forming process conditions have to be developed. In this study, the warm deep drawing process of AZ31 sheets is studied numerically by non-isothermal simulation. The difference between the isothermal simulation results and the non-isothermal simulation results and the progress of warm forming are discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.05a
• /
• pp.846-851
• /
• 2003

The differential equations governing free, in-plane vibrations of non-circular arches with non-uniform cross-section, including the effects of rotatory inertia, shear deformation and axial deformation, are derived and solved numerically to obtain frequencies. The lowest four natural frequencies are calculated for the prime parabolic arches with hinged-hinged, hinged-clamped, and clamped-clamped end constraints. Three general taper types for rectangular section are considered. A wide range of arch rise to span length ratios, slenderness ratios, and section ratios are considered. The agreement with results determined by means of a finite element method is good from an engineering viewpoint.

• Structural Engineering and Mechanics
• /
• v.19 no.6
• /
• pp.749-755
• /
• 2005

In this work, thermo-elastic stability behavior of laminated cross-ply elliptical cylindrical shells subjected to uniform temperature rise is studied employing the finite element approach based on higher-order theory that accounts for the transverse shear and transverse normal deformations, and nonlinear in-plane displacement approximations through the thickness with slope discontinuity at the layer interfaces. The combined influence of higher-order shear deformation, shell geometry and non-circularity on the prebuckling thermal stress distribution and critical temperature parameter of laminated elliptical cylindrical shells is examined.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.8
• /
• pp.1707-1714
• /
• 1997

This paper proposes a novel algorithm for fractal coding of image sequence, based on the CPM (Circular Prediction Mapping) and the NCIM (Non Contractive Interframe Mapping). In the CPM and the NCIM, each range block is approximated by a domain block in the adjacent frame, which is of the same size as the range block. Also, in this paepr, we propose a coding scheme of color components and an algorithm for controlling the bit rate, resepectively, for practical implementation of the fractal coder. The computer simulation results on real image sequences demonstrate that the proposed algorithm provides very promising performance at low bit-rate, below 256 Kbps.

• Tribology and Lubricants
• /
• v.22 no.2
• /
• pp.79-86
• /
• 2006

As the gerotor set with ideal profile meshes too tight, the reduction in the size of the rotor is generally adopted for a smooth operation. In this paper, a method of the profile modification for providing clearances was proposed. The meshing properties of the gerotor were analyzed and the non-boundary section of the inner rotor was identified, which denoted that the adjacent chambers were in the same pressure state. Clearances were imposed on the non-boundary section of the inner rotor, and then the profile of that section was modified as a composite curve of arcs. The other sections of the inner rotor were also interpolated as arcs. Thus, the whole profile of the inner rotor was designed as a composite curve of arcs.

• Water for future
• /
• v.29 no.1
• /
• pp.249-263
• /
• 1996

Presented herein are the results of a laboratory study on structural loads (icing weight and wind loads) associated with icing formation on rigidly fixed, circular power-transmission cables and cylinders. The experiments were carried out using movable wind tunnel under two different conditions: refrigerated and non-refrigerated conditions. Temporal evolution of icing loads were determined in the refrigerated laboratory and wind loads for icings at several stages of icing formation were measured in the non-refrigerated laboratory.

• Wind and Structures
• /
• v.1 no.1
• /
• pp.59-66
• /
• 1998

The vibrations of bodies subjected to fluid flow can cause modifications in the flow conditions, giving rise to interaction forces that depend primarily on displacements and velocities of the body in question. In this paper the linearized equations of motion for bodies of arbitrary prismatic or cylindrical cross-section in two-dimensional cross-flow are presented, considering the three degrees of freedom of the body cross-section. By restraining the rotational motion, equations applicable to circular tubes, pipes or cables are obtained. These equations can be used to determine stability limits for such structural systems when subjected to non uniform cross-flow, or to evaluate, under the quasi static assumption, their response to vortex or turbulent excitation. As a simple illustration, the stability of a pipe subjected to a bidimensional flow in the direction normal to the pipe axis is examined. It is shown that the approach is extremely powerful, allowing the evaluation of fluid-structure interaction in unidimensional structural systems, such as straight or curved pipes, cables, etc, by means of either a combined experimental-numerical scheme or through purely numerical methods.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.6 no.2
• /
• pp.108-116
• /
• 2011

Non-line-of-sight (NLOS) error is the most common and also a major source of errors in wireless location system. A novel weighting factor (NWF) method is presented in this paper, based on the RSS(Received Signal Strength) measurements, path loss model and Circular Disk of Scatterers Model (CDSM). The proposed positioning method effectively weighted the TOA distance measurements for each Base Station (BS). Simulation results show that the proposed method efficiently weighted the distance measurements and achieve higher localization accuracy than that of Linear Line of Position (LLOP) and Believable Factor Algorithm (BFA).

• Journal of Venture Innovation
• /
• v.1 no.1
• /
• pp.29-47
• /
• 2018

As the radical advances of digitalization, our daily life have been fundamentally changed. As a result, the customer journey also changed as compared with previous periods. This study analyzed customer journy of digital age. First, historical trends and issues of customer journey research were analyzed. Second, Comparative analysis of customer journey of digital and previous age were conducted. No more funnel model of customer journey which assumed hierarchical and linear paths was valid. Customer journey of digital age will be non-linear and circular paths.