• 한국공간정보시스템학회:학술대회논문집
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• 2004.05a
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• pp.131-138
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• 2004

The cable structure is a kind of ductile structural system using the tension cable and compression column as a main element. From mechanical characteristics of the structural material, it is profitable to be subjected to the axial forces than bending moment or shear forces. And we haweto consider the local buckling when it is subjected to compression forces, but tension member can be used until the failure strength. So we can say that the tension member is the most excellent structural member. Cable dome structures are made up of only the tension cable and compression column considering these mechanical efficiency and a kind of structural system. In this system, the compression members are connected by using tension members, not connected directly each other. Also, this system is lightweight and easy to construct. But, the cable dome structural system has a danger of global buckling as external load increases. That is, as the axisymmetric structure is subjected to the axisymmetric load, the unsymmetric deformation mode is happened at some critical point and the capacity of the structure is rapidly lowered by this reason. This phenomenon Is the bifurcation and we have to reflect this in the design process of the large space structures. In this study, We investigated the nonlinear unstable phenomenon of the Geiger, Zetlin and Flower-type cable dome.

• Korean Chemical Engineering Research
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• v.52 no.4
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• pp.516-521
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• 2014

Axial and overall heat transfer coefficients were investigated in a bubble column with relatively high viscous and low surface tension media. Effects of superficial gas velocity (0.02~0.1 m/s), liquid viscosity ($0.1{\sim}0.3Pa{\cdot}s$) and surface tension ($66.1{\sim}72.9{\times}10^{-3}N/m$) on the local and overall heat transfer coefficients were examined. The heat transfer field was composed of the immersed heater and the bubble column; a vertical heater was installed at the center of the column coaxially. The heat transfer coefficient was determined by measuring the temperature differences continuously between the heater surface and the column which was bubbling in a given operating condition, with the knowledge of heat supply to the heater. The local heat transfer coefficient increased with increasing superficial gas velocity but decreased with increasing axial distance from the gas distributor and liquid surface tension. The overall heat transfer coefficient increased with increasing superficial gas velocity but decreased with increasing liquid viscosity or surface tension. The overall heat transfer coefficient was well correlated in terms of operating variables such as superficial gas velocity, liquid surface tension and liquid viscosity with a correlation coefficient of 0.91, and in terms of dimensionless groups such as Nusselt, Reynolds, Prandtl and Weber numbers with a correlation of 0.92; $$h=2502U^{0.236}_{G}{\mu}^{-0.250}_{L}{\sigma}^{-0.028}_L$$ $$Nu=325Re^{0.180}Pr^{-0.067}We^{0.028}$$.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.05a
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• pp.39-43
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• 2002

A new model for heat transfer and thermal deformation analysis according to strip mm in coiling process has been proposed. Finite difference analyses for heat transfer of cold rolled coil have been carried out under various coiling tensions and strip crown using the equivalent thermal conductivity for the radial direction of cold rolled coil which is a function of strip thickness, surface characteristics and compressive pressure. The compressive pressure is calculated from a equation expressed as a function of hoop stress and coil tension considering strip mm obtained by experiment. Finite element method for thermal deformation of cold rolled coil has been performed to investigate the effects of the strip crown, the coil tension and temperature. From these analyses, it is found that the axial inhomogeneity of thermal deformation is increased as the strip crown, compressive pressure, and temperature drop in cold coiled strip increase.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.192-199
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• 2002

The use of frequency-dependent dynamic stiffness matrix (or spectral element matrix) in structural dynamics may provide very accurate solutions, while it reduces the number of degrees-of-freedom to improve the computational efficiency and cost problems. Thus, this paper develops a spectral element model for the thin plates moving with constant speed under uniform in-plane tension. The concept of Kantorovich method is used in the frequency-domain to formulate the dynamic stiffness matrix. The present spectral element model is evaluated by comparing its solutions with the exact analytical solutions. The effects of moving speed and in-plane tension on the flexural wave dispersion characteristics and natural frequencies of the plate are numerically investigated.

• Journal of the Korean institute of surface engineering
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• v.48 no.3
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• pp.93-99
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• 2015

This test focuses on the correlations between joining axial force at non-room temperature and at room temperature according to the surface treatment (Geomet, Dacro, Green Kote, Armore Galv.). The quality characteristics of the fastening axial force required by the KSB 2819 and EN14399-10 standards were discussed. Surface treatment was implemented to S10T and 10.9HRC sets of bolts under the same environmental factors. Development for the stabilization of the fastening axial force required by each standard should continually be enforced, and the fastening and storage in the field should be maintained at room temperature. Managing stabilization of torque enumerated data is required after application of surface treatment. It is concluded that, by conducting the test of applying surface treatment to effectively manage, each lot-specific rate of axial force at room temperature conditions should be maintained below the maximum 4.47%. The decline rate of axial force should be maintained under 2.15% maximum, and the standard deviation of the room temperature condition should be maintained below 0.5.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2A
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• pp.103-111
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• 2010

A feasibility study for nondestructively estimating prestress force of a grouted tendon using axial vibrations has been investigated. Total eight prestressed concrete beams with different stress levels have been specially designed and constructed for this investigation. The various axial vibration tests have been conducted in order to extract the dynamic characteristics of the prestressed concrete beams. It turns out that the axial frequency, elastic wave velocity and elastic modulus are nonlinearly increased as the prestress force level increases. It seems that the axial vibration characteristics of the existing grouted tendons are a feasible indicator for the identification of their tensile force.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.4
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• pp.53-62
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• 1998

Experimental studies for the laminated elastomeric bearing and the lead-rubber bearing, those are often used to improve the seismic capacity of the structures recently, are conducted to evaluate the seismic capacity of the bearings. The shear stiffness of the bearings decreases as the shear strain amplitude or the constant axial load level increases, but not sensitive to the strain rates effect. Bearings are strong for the axial compression but weak for the axial tension.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.430-433
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• 2006

The reinforced concrete column confined by square steel tubes(RCST) is a reinforced column (RC) confined by thin steel tubes which cover over the full length of the column but terminates 15mm from the column's ends. The steel tube is in uniaxial tension stress state and won't buckle when the column sustains axial load. This will highly increase the bearing capacity and ductility of the columns. The hysteretic behavior of four square RCST columns and one square RC column were experimentally studied under constant axial load and lateral cyclic load. The wide-to-thickness (D/t) ratio of RCST columns employed in this research is 75. The main variables of the experiment were axial load ratio and compressive strength of the concrete. Based on the findings in this research, RCST columns exhibits high lateral strength, ductility, and energy dissipation ability.

• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.149-159
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• 2004

Dynamic analysis of laminated beams with a embedded damping layer under tensional and compressive axial load is investigated. Improved Layer-Wise Zig-Zag Beam Theory and Interdependent Kinematic Relation are incorporated to model the laminated beams with a damping layer and a corresponding beam zig-zag finite element is developed. Flexural frequencies and modal loss factors under tension or compression axial load are calculated based on Complex Eigenvalue Method. The effects of the axial tensional and compressive load on the frequencies and loss factors are discussed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.209-216
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• 2000

The purpose of this study is to investigate elasto-plastic behaviour and estimate ultimate resistance capacity of the residential-commercial building subjected to lateral force along the height of structure. Four types of residential-commercial building are chosen as analytical models and investigated by pushover analysis. Pushover analysis estimates initial elastic stiffness, post-yielding stiffness, and plastic hinges on each story of structures through three-dimensional nonlinear analysis program CANNY-99. Skeleton curve of bending stiffness model is bilinear, shear stiffness model is trilinear, and axial stiffness model is elastic. Skeleton curve of axial stiffness model has the axial compression and tension stiffness of reinforced concrete members. This study presents the change of inter story drift, story stiffness and hinge of story and member.