• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.325-332
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• 2003

The tube structures act like cantilevered box beams and effectively resist lateral loads. In result, they are adopted as a high-rise buildings system. However, the shear lag in tube system prevents the idealized tube behavior such as a cantilevered box beam. Therefore, the studies on shear lag phenomena are necessarily requested. The presented papers are almost studied on framed tube structures and tube in tube structures. However, the study on the shear lag in the tube structure with core wall is lack. Thus, in this paper, the shear lag of the structure is studied. The shear lag coefficient is defined to investigate shear lag phenomena. However, existing shear lag coefficients are not adequate for understanding them. Therefore, on this study, new shear lag coefficient is suggested. In addition, the shear lag in the tube structure with core wall is analyzed by changing the five structural parameters of stiffness factor in frame, stiffness factor in wall, stiffness ratio, the number of stories and the number of bays.

• Journal of Sensor Science and Technology
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• v.23 no.1
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• pp.19-23
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• 2014

A new hydraulic tube structure for WIM sensor of a new generation is presented in this paper. The double-tube structure has been developed in order to improve the performance of the hydraulic load cell. The double-tube structure hydraulic element could be reduced by 46% in pressure changes according to temperature compared to a single-tube structure. In addition to the nonlinearity can be reduced by 67.19% at the same load condition. The hydraulic load cell shows an excellent linearity and measurement accuracy as the result of the static load test.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2004.05a
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• pp.21-25
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• 2004

The column for Steel Framed Reinforced Concrete Structure (SFRCS) and the column for Reinforced Concrete Structure (RCS) could be the most common building structure. The increasing of the need for massive space hasaffected the size of building components for supporting the massive structure. However, the changing of components size makes inefficient space of building. Hence, to meet the need for acquiring efficient space comparing the budget and cost the new structure method, Concrete Filled Tube Steel (CFT), was developed. CFT is the structure for which steel tube instead of other materials such as wood for holding concrete is used. The most benefit of this one is to help in reducing the size of the building components and local buckling because of tube steel holding concrete. For this reason, this research will examine the probability of applying CFT on construction sites by using the concrete (800kgf/$\textrm{cm}^2$) especially for CFT through the data from the real size mock-up.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.812-818
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• 2001

The drop type impact test and finite element analysis are established for examining the buckling behavior of a square tube under the lateral impact load. Based on these results, the effects by the boundary conditions for supporting the structure are reviewed, which are as follows. One is pinned condition by screw; the other is fixed by welding. The critical impact force and acceleration by test are nearly same between two cases. However, the critical impact velocity of the pinned condition is higher than that of the fixed case. Therefore, the dynamic buckling behavior of a pinned structure is better than the fixed condition in view of critical impact velocity. These test and analysis results will be adaptable for predicting the dynamic structural integrity of a tube structure not only the axial impact event but the lateral impact event.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.572-583
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• 2019

This paper aims to assess the applicability of the Runge Kutta Discontinuous Galerkin-Direct Ghost Fluid Method to the internal explosion inside a water-filled tube, which previously was studied by many researchers in separate works. Once the explosive charge located at the inner center of the water-filled tube explodes, the tube wall is subjected to an extremely high intensity fluid loading and deformed. The deformation causes a modification of the field of fluid flow in the region near the water-structure interface so that has substantial influence on the response of the structure. To connect the structure and the fluid, valid data exchanges along the interface are essential. Classical fluid structure interaction simulations usually employ a matched meshing scheme which discretizes the fluid and structure domains using a single mesh density. The computational cost of fluid structure interaction simulations is usually governed by the structure because the size of time step may be determined by the density of structure mesh. The finer mesh density, the better solution, but more expensive computational cost. To reduce such computational cost, a non-matched meshing scheme which allows for different mesh densities is employed. The coupled numerical approach of this paper has fewer difficulties in the implementation and computation, compared to gas dynamics based approach which requires complicated analytical manipulations. It can also be applied to wider compressible, inviscid fluid flow analyses often found in underwater explosion events.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2200-2206
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• 2008

This paper describes the results of experiments on the bending behavior of welded square tube structures for drive shaft sub frame of BIMODAL Tram. The used specimens to test were two different type made of ATOS60 and ST52-3. The square tube made of ST52-3 is the non-welded structure, while the square tube made of ATOS60 is the welded structure. The welded square tube made of ATOS60 will be applied for drive shaft sub frame of BIMODAL Tram. This welded square tube could reduce the manufacturing cost in comparison of non-welded square tube. The results showed that the bending performance of welded square tube made of ATOS60 was proven, and the bending behavior was in an good agreement with that of nonlinear finite element analysis.

• Journal of the Korean Society for Railway
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• v.13 no.5
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• pp.516-520
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• 2010

Parametric study has been conducted to calculate the capacity of vacuum pump system that will be used to maintain the pressure of the tube structure under atmosphere level. Recently many railroad researchers pay attention to the tube train system as one of the super high speed transportation system. To achieve the super high speed, the inside of tube system should be maintained at low pressure level. In the low pressure environment, it is well known that air resistance of train is drastically decreased. Vacuum pump system will be used to make low pressure state for tube structure, exhaust the leakage air and supplement additional vacuum pumping. As results of these studies, we get the lump capacity of vacuum pump for various parameters. These results can be applied to analyze the effects of the reduction of air resistance.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.3
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• pp.86-94
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• 2015

A series of injection and drainage test were conducted on an circular acrylic tube to investigate the pressure generated by the accumulated fill materials inside a circular acrylic tube structure. The acrylic tube was filled by means of gravity filling with a slurry material having an average water content of 700%. The water head during the filling process was 1.8m and the bottom pressure during initial filling was 20.18kPa. The recorded stress at the sides of the acrylic tube was 17.89kPa during the filling process and was reduced to 13.58kPa during the leaving process. Continuous drainage of the acrylic tube has greatly influenced the stresses around the tube structure. As the water is gradually allowed to overflow, the generated pressure at the topmost pressure sensor of the tube was reduced further to 2.17kPa. Eventually, the initially liquid state slurry material transforms into plastic state after water has dissipated and substantial soil particles are deposited in the acrylic tube. The final water content of the deposited silt inside the acrylic tube after the test was 42%. It was found that the state of stresses(geo-static earth pressures) in the acrylic tube was anisotropic rather than isotropic.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.2
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• pp.125-132
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• 2011

The rupture of an expansion tube is mainly affected by the expansion ratio and the external shape of the punch used to expand the tube. In order to prevent the tube from rupture, the effect of the external shape of the punch should be considered in the design. The aim of this paper is to confirm the effect of key design parameters of the punch on rupture of the tube using a finite element analysis with a ductile damage model. The results of the analysis indicated that the expansion ratio of the tube was mainly affected by variation of the radius of the punch. However, the rupture was more affected by variation of the punch angle than the radius of the punch. The existence of a specific punch angle at which rupture did not occur, even if the radius of the punch was increased, was found from the results.

• Journal of the Korean Society of Safety
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• v.15 no.3
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• pp.45-51
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• 2000

This paper studies the effect of vibrational characteristics of the various tubes analyzed though experiment. By an experiment analysis we found out that the factor of system vibration is fluid-structure interaction of tube line. In fluid-filled tube system we study on the influence that the natural frequency of system and the frequency of wave motion produce upon through three experiments. Three experiments are modal test on each tube, FRF in continuous system, and vibrating tests when the system is driving on. From the results of the experimental studies, we obtained that the natural frequencies of system are very important than wave induced vibrations. and according to the variation of configuration, the frequencies are different each other. And we found that though fluid passed away through the tube, the tendency of system vibration level was similar with the mode shape at the simple system.