• Geomechanics and Engineering
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• v.16 no.2
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• pp.151-157
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• 2018

The constrained conditions of roof and floor for the coal pillar affect the strength of coal pillar very seriously. To analyze the influence of rock mass for the roof and floor on the stability of coal pillar comprehensively, one method based on the mechanical method for the composite rock mass was proposed. In this method, the three rock layers of roof, floor and coal pillar are taken as the bedded composite rock mass. And the influence of rock mass for the roof and floor on the elastic core of coal pillar has been analyzed. This method can obtain not only the derived stress by the cohesive constraining forces for the coal pillar, but also the derived stress for the rock mass of the roof and floor. Moreover, the effect of different mechanical parameters for the roof and floor on the stability of coal pillar have been analyzed systematically. This method can not only analyze the stability of strip coal pillar, but also analyze the stability of other mining pillars whose stress distribution is similar with that of the strip coal pillar.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.7 s.94
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• pp.1686-1699
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• 1993

In this paper, the thermal buckling of thick composite angle-ply laminates subject to uniform temperature distribution is studied. For the plates of 4-edges simply supported condition and those of 4-edges clamped condition, the critical buckling temperatue is derived, using tile finite element method based on the shear deformation theory. The effects of lamination angle, layer number, laminate thickness, plate aspect ratio and boundary constraints upon the critical buckling temperature are presented.

• Journal of the Korean Society for Advanced Composite Structures
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• v.4 no.3
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• pp.1-6
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• 2013

In this study, a shape of connector on seismic reinforced strip, which did not cause any physical damage to concrete column and can repair and reinforcement was decided by using nonlinear finite element analysis. Load displacement was applied on the concrete attached by strip. Stress distribution of connector by extension of concrete were checked. Through stress distribution of this analysis results, the most favorable shape was selected as a shape of the connector.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.709-712
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• 2002

For the electro-discharge machining of an electro-conductive anisotropic composite, an unsteady state formulation was established and solved by Galerkin's finite element method. The distribution of temperature on work piece, the shape of the crater and the material removal rate were obtained in terms of the process parameters. As the spark was initiated the workpiece immediately started to melt and the heat affected zone was formed. The moving boundary of the crater was also identified with time. When the radial and axial conductivities were increased separately the temperature distribution and the shape of the crater were shifted in the same direction respectively and the material removal rate was found to be higher in the case of increasing radial conductivity rather than the axial conductivity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.306-310
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• 1996

In this paper a series of developing process for an insulator which can be employed in overhead distribution lines, using polymeric composite materials, is introduced. In order to design an insulator for heavily polluted area, weathershed of alternating type was adopted, which could have longer leakage distance. Modified EVA was used as surface material which has good electrical and mechanical characteristics as well as superior chemical stability. FRP core was covered with above surface material through heat shrinking process. By standardization of each process, higher productivity and lower production cost could be ensured. The developed insulator has been put under various tests including long-term field test and artificial aging test and satisfactory results were obtained.

• Computational Structural Engineering : An International Journal
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• v.3 no.1
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• pp.19-29
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• 2003

In the present study, finite element linear buckling analysis is performed for grid-stiffened composite plates. A hybrid element with drilling degrees of freedom is employed to reduce the effect of the sensitivity of mesh distortion and to match the degrees of freedom between skins and stiffeners. The preliminary static stress distribution is analyzed for the determination of accurate load distribution. Parametric study of grid structures is performed and three types of buckling modes are observed. The maximum limit of buckling load was found at the local skin-buckling mode. In order to maximize buckling loads, stiffened panels need to be designed to be buckled in skin-buckling mode.

• Proceedings of the Korea Concrete Institute Conference
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• 1992.04a
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• pp.137-142
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• 1992

The purpose of this study is to develop a new structural system for precast deck plate bridge. In order to investigate load distribution and composite effects by connecting diaphragms and precast deck plate to main girder with shear keys, computer analysis with F.E.M S/W package program ADINA was carried out. As results of analysis, the following could be concluded : -The distance between diaphragms with6m is suficient for crossing load distribution effects. -The composite effects by connection deck plate to main girder with shear key is reasonable. -The gap between deck plate and main girder under given load is negligible.

• Structural Engineering and Mechanics
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• v.56 no.6
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• pp.983-1001
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• 2015

This study focuses on the load carrying capacity and the force transfer mechanism of multi-hole perfobond shear connectors in steel-concrete composite structure. The behavior of multi-hole perfobond shear connector is more complicated than single-hole connector cases. 2 groups push-out tests were conducted. Based on the test results, behavior of the connection was analyzed and the failure mechanism was identified. Simplified iterative method and analytic solution were proposed based on force equilibrium for analyzing multi-hole perfobond shear connector performance. Finally, the sensitivity of design parameters of multi-hole perfobond shear connector was investigated. The results of this research showed that shear force distribution curve of multi-hole perfobond shear connector is near catenary. Shear forces distribution were determined by stiffness ratio of steel to concrete member, stiffness ratio of shear connector to steel member, and number of row. Efficiency coefficient was proposed to should be taking into account in different limit state.

• Structural Engineering and Mechanics
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• v.25 no.6
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• pp.753-765
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• 2007

The response histories and distribution of dynamic interlaminar stresses in composite laminated plates under free vibration and thermal load is studied based on a thermoelastodynamic differential equations. The stacking sequence of the laminated plates may be arbitrary. The temperature change is considered as a linear function of coordinates in planes of each layer. The dynamic mode of displacements is considered as triangle series. The in-plane stresses are calculated by using geometric equations and generalized Hooke's law. The interlaminar stresses are evaluated by integrating the 3-D equations of equilibrium, and utilizing given boundary conditions and continuity conditions of stresses between layers. The response histories and distribution of interlaminar stress under thermal load are presented for various vibration modes and stacking sequence. The theoretical analyses and results are of certain significance in practical engineering application.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.191-194
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• 2005

Impact properties of glass/Kevlar hybrid composites which have 3-D braided structures were studied. Results were compared to those of composites made of only glass fibers where the same epoxy resin were used as matrix. Absorbed impact energies evaluated through the combination of the data from the impact tester and high speed camera were compared to each other. In order to see the difference between the damaged area distribution CCD camera captures were performed.