• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.162-163
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• 2015

Thermal deformation behavior of high-strength concrete (HSC) exposed to fire is different from that of normal strength concrete (NSC). In case of ultra-high-strength concrete (UHSC), it is well known that thermal deformation behavior is greater than HSC. With increasing research of UHSC in buildings, it is necessary to understand the performance of UHSC at elevated temperatures considering loading condition. Therefore, evaluation on properties of thermal strain behavior properties of ultra high strength concrete by loading and high temperature was conducted.

• Tribology and Lubricants
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• v.12 no.4
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• pp.52-59
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• 1996

The results of the electrical contact conductivity of multi-contact spots accounting the surface roughness and the non-conductive films of different origins such as air, water, cutting oil, and machining oil are presented. The array of metal spheres compressed between two flat plates has been used for simulation of the contact behavior of multiple contact of solids, under normal loading. Measurement of electrical contact resistance has been made using the equipment providing the adequate accuracy in the range of micro Ohms. The data on electrical contact resistance have been compared with theoretical predictions using the multiple contact model of constriction resistance. The effect of single spot number and array on conductivity of contact has been evaluated. The results of the experiments show that the contact resistance are closely related to the number of loading cycles, form of surface roughness, and presence of non-conductive films that reduce the size of the real electrical contact spots.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.11
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• pp.188-193
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• 2003

To predict changes in biomechanical parameters such as intradiscal pressure, and the shock absorbing mechanism in the spinal motion segment under different impact duration/loading rates, a three dimensional L3/L4 motion segment finite element model was modified to incorporate the poroelastic properties of the motion segment. The results were analyzed under variable impact duration for normal and degenerated discs. For short impact duration and a given maximum compressive force, relatively high cancellous pore pressure was generated as compared with a case of long impact duration, although the amount of impulse was increased. In contrast relatively constant pore pressure was generated in the nucleus. Disc degeneration increased pore pressure in the disc and decreased pore pressure in the cancellous core, which is more vulnerable to compressive fracture compared with intact case.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.812-815
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• 2007

Computational simulation has been performed to design the filtration system for Korea model IGCC demonstration plant. The filtration system for optimal design has four effective filters corresponding to the clusters composed of a group of ceramic candle filters. It was analyzed how the different entrance geometry influences the flow field and the particle behavior in the filtration system. The particle loading is minimum when the gas mixed with particles flows into the filter vessel with a shroud tube through a tangential inlet. However, the particle loading is maximum when the gas with particles enters the filter vessel through a normal inlet which a entrance tube extended from. By controling adequately both conditions of inflow, the filtration system can be operated optimally to prolong the filter life-time and to save the energy for cleaning filters.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.2
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• pp.473-480
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• 1996

Automatic fatigue crack length measuring system using DC electrical potential method and the system control program for automatic fatigue testing under random load condition were made in this study. And using these system and control program, fatigue tests were executed under constant and random load condition. As the result, the propagation of crack in random loading can be represented Paris equaiton and log normal probability function. But constant and random load test show different crack propagation properties.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.379-385
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• 2001

A series of standard consolidation tests and repeated loading consolidation tests were peformed with 2 kinds of peat sampled in Chonbuk area to study the consolidation characteristics of peat. The samples had following physical properties : 58% and 72% of organic content, 487% and 685% of natural moisture content and 7.02 and 9.72 of initial void ratio, respectively. And compression index $C_{c}$ and coefficient of secondary consolidation $C_{\alpha}$ were increased steeply when the consolidation load exceed about 2.5 and 3 times of each preload as like the characteristics of peat. The dependance on consolidation pressure of $C_{C}\;and\;C_{\alpha}$ in peatl and the maximum values, 2.9-3.8 and 0.3-0.4 were larger than that of normal clay, respectively.

• Journal of Welding and Joining
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• v.8 no.4
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• pp.69-75
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• 1990

In this paper, ultimate compressive strength of TMCP 50HT steel plates (yield stress .sigma.$_{o}$=36kg/mm$^{2}$) with HAZ softening is studied. Finite element method formulated by the author is applied to analyze the elasto-plastic large deflection behaviour of the plates. The influence of HAZ softening breadth, welding direction and slenderness ratio on the ultimate compressive strength is investigated. The results obtained are summarized as 1) With the increasing of the HAZ softening breadth, early plasticity on the plates is formed and then the ultimate compressive strength is decreased, in which about 8% of the ultimate strength for the plate with h/t=4(h: HAZ softening breadth, t: plate thickness) was reduced comparing with no HAZ softening. 2) The large decrease of the ultimate strength for the case that the welding direction is normal to the loading direction is occurred than the case that the welding direction is parallel to the loading direction. 3) The influence of HAZ softening on the ultimate compressive strength is serious for thick plates, while it may be negligible for thin plates.s.

• Steel and Composite Structures
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• v.9 no.6
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• pp.519-534
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• 2009

This study intends to examine the characteristics of compressive behavior and conducts comparative analysis between normal compressive strength under existing equations (LRFD, ACI 318, EC 4) and experimental the maximum compressive strength from the compression experiment for the unstiffened steel plate-concrete structures. The six specimens were made to evaluate the constraining factor (${\xi}$) and width ratio (${\beta}$) effects subjected to the compressive monotonic loading. Based on this experiments, the following conclusions could be made: first, compressive behaviors of the specimens from the finite element analysis closely agreed with the ones from the actual experiments; second, the higher the width ratio (${\beta}$) was, the lower the ductility index (DI) was; and third, the test results showed the maximum compressive strength with a margin by 7% compared to the existing codes.

• Steel and Composite Structures
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• v.36 no.3
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• pp.249-259
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• 2020

In this work, a novel three-dimensional model in the generalized thermoelasticity for a homogeneous an isotropic medium was investigated with diffusion, under the effect of thermal loading due to laser pulse in the context of Green-Lindsay theory was investigated. The normal mode analysis technique is used to solve the resulting non-dimensional equations of the problem. Numerical results for the displacement, the thermal stress, the strain, the temperature, the mass concentration, and the chemical potential distributions are represented graphically to display the effect of the thermal loading due to laser pulse and the relaxation time on the resulting quantities. Comparisons are made within the theory in the presence and absence of laser pulse.

• Computers and Concrete
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• v.12 no.4
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• pp.537-552
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• 2013

Computation of flexural ductility of reinforced concrete beam sections has been proposed by taking into account strain rate sensitive constitutive behavior of concrete and steel, confinement of core concrete and degradation of cover concrete during load reversal under earthquake loading. The estimate of flexural ductility of reinforced concrete rectangular sections has been made for a wide range of tension and compression steel ratios for confined and unconfined concrete at a strain rate varying from $3.3{\times}10^{-5}$ to 1.0/sec encountered during normal and earthquake loading. The parametric studies indicated that flexural ductility factor decreases at increasing strain rates. Percentage decrease is more for a richer mix concrete with the similar reinforcement. The confinement effect has marked influence on flexural ductility and increase in ductility is more than twice for confined concrete (0.6 percent volumetric ratio of transverse steel) compared to unconfined concrete. The provisions in various codes for achieving ductility in moment resisting frames have been discussed.