• Steel and Composite Structures
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• v.18 no.1
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• pp.273-288
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• 2015

As one of the most common failure types of arch bridges, stability is one of the critical aspects for the design of arch bridges. Using 3D finite element model in ABAQUS, this paper has studied the stability performance of an arch bridge with inclined arch ribs and hangers, and the analysis also took the effects of geometrical and material nonlinearity into account. The impact of local buckling and residual stress of steel plates on global stability and the applicability of fiber model in stability analysis for steel arch bridges were also investigated. The results demonstrate an excellent stability of the arch bridge because of the transverse constraint provided by transversely-inclined hangers. The distortion of cross section, local buckling and residual stress of ribs has an insignificant effect on the stability of the structure, and the accurate ultimate strength may be obtained from a fiber model analysis. This study also shows that the yielding of the arch ribs has a significant impact on the ultimate capacity of the structure, and the bearing capacity may also be approximately estimated by the initial yield strength of the arch rib.

• Journal of Korean Society of Steel Construction
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• v.18 no.1
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• pp.59-69
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• 2006

This paper presents test results on reduced beam section (RBS)program addressed panel zone (PZ) strength as the key variables. PZ strength has been much debated issue for several decades. A desirable range of PZ strength has not yet been proposed despite the fact that a significant amount of RBS test data is available. Test results from this study and by others showed that panel zones could easily develop a plastic rotation of 0.01 radian without causing distress to the beam flange groove welds. At this deformation level, the amount of beam distortion (i.e., buckling) was about one half that developed in strong PZ specimens. A criterion for a balanced PZ strength that improves the plastic rotation capacity while reducing the amount of beam buckling is proposed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.952-958
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• 1988

To analyze the nonflatness and residual stress in accelerated cooled plate, a numerical analysis model has been developed. Two factors, i.e. temperature and phase transformation, are considered in calculating the stress distribution that develops during cooling. The plastic strain and plate-buckling, which are often shown in accelerated cooled plate, were determined from this stress. Mean temperature in through thickness direction and temperature difference in width direction are considered in the model to simplify the calculation. The temperature and stress distribution changes caused by phase transformation are involved in terms of the effective specific heat and the effective thermal expansion coefficient. With the model, accelerated cooling of 10mm(t) $^{*}$3000mm(w) plate was simulated. The condition of accelerated cooling was .deg. C/sec from just after hot rolling to 500.deg. C. The initial temperature-difference ratio, .DELTA.Tr, in width direction is an important factor in evaluating the stress distribution. When .DELTA.Tr is 0.08, buckling occurs during cooling and 7kgf/m $m^{2}$ of residual stress develops at the edge of plate. To secure the flatness, .DELTA.Tr should be less than 0.07. Small scaled cooling test was conducted to verify the exactness of the model and the results proved the usefulness of this numerical analysis model.l.

• Computers and Concrete
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• v.5 no.6
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• pp.525-544
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• 2008

In this research, the self-centering effect in precast and prestressed reinforced concrete structures was investigated experimentally. The reinforced concrete beams and columns were precast and connected by post-tensioning tendons passing through the center of the beams as well as the panel zone of the connections. Three beam-to-interior-column connections were constructed to investigate parameters such as beam to column interfaces (steel on steel or plastic on plastic), energy dissipating devices (unbonded buckling restrained steel bars or steel angles) and the spacing of hoops in the panel zone. In addition to the self-centering effect, the shear strength in the panel zone of interior column connections was experimentally and theoretically evaluated, since the panel zone designed by current code provisions may not be conservative enough to resist the panel shear increased by the post-tensioning force.

• Journal of Welding and Joining
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• v.17 no.5
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• pp.55-60
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• 1999

In thin plate welding, welding deformation is deformation is produced in special form like buckling distortion, which is different from one in thick plate welding, large quantitatively, and has complicated form. Therefore, a particular countermeasure to prevent the welding deformation in manufacturing process is requested. Otherwise it takes more time to straighten the welding deformation than to fabricated a steel structure newly and in case of failing to straighten the welding deformation in beginning of the flame straightening process, even if the flame straitening is completed, the appearances is not good and sometimes eve refabrication is needed. To minimize these problems. In this present paper, the effects of the condition of support pin on out-of plane deformation produced by thin plate Butt welding in investigated through experiment and the countermeasure to prevent the welding deformation in suggested.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.5
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• pp.504-508
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• 2007

In the case of thin plate blocks, buckling deformation due to longitudinal shrinkage is the most important weld-induced deformation. This paper is concerned with developing the formula to predict the longitudinal shrinkage due to welding, in which mechanical tension effect in welding direction is accounted for. For this purpose, bead on plate welding test has been carried out for the 27 thin plate specimens with varying welding conditions and magnitude of tensile load. Empirical formula of predicting the longitudinal shrinkage has been derived based on the results of welding test, in which effect of mechanical tension is included. The derived formula can be usefully used in predicting the level of tensile load to reduce the longitudinal shrinkage.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.43-50
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• 2002

Main goal of this study is to develop MATLAB programming for exact analysis of distortional deformation of the straight box girder. For this purpose, a theory for distortional deformation theory is firstly summarized and then a BEF (Beam on Elastic Foundation) theory is presented using analogy of the corresponding variables. Finally, the governing equation of the beam-column element on elastic foundation is derived. An element stiffness matrix of the beam element is established via a generalized linear eigenvalue problem. In order to verify the efficiency and accuracy of the element using exact dynamic stiffness matrix, buckling loads for the continuous beam structures with elastic foundation and distortional deformations of box girders are calculated.

• Journal of the Korean institute of surface engineering
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• v.38 no.1
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• pp.14-20
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• 2005

The control of internal stress is extremely important in electroforming because of the deliberately low adhesion between the electro form and the mandrel. Excessive tensile or compressive stress can cause distortion, separation problem, curling, peeling or separation of electroform prematurely from the mandrel, buckling and blistering. Nickel sulfamate bath has been widely used in electroforming because of its low internal stress and moderate hardness. In this study, real-time stress sensor has been used for stress control in chloride-free nickel sulfamate bath for 400 mm x 300 mm x 500 ㎛ nickel electroform. It was found that compressive stress found at low current density indicated the contamination of electrolyte, which is very useful in procuring buckling and peeling of electroform. No compressive stress is allowed for plate electroform. The real-time stress can also be used for accurate stress control of nickel electroform. The tensile stress was found to be increased slightly with increase in nickel electroform thickness, i.e., from initial 1.47 ksi to 2.02 ksi at 320 ㎛.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.4
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• pp.351-359
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• 2007

Multi-axial compression tests have been frequently conducted to evaluate the in situ properties of rock masses and the mechanical behaviors of rock strata through the model tests. Without the proper boundary condition for the model tests, the mechanical behavior of rock mass would deviate, as can be expected, from the in situ conditions. The boundary condition will affect the internal stress distribution of the specimens and cause some distortion on the measurement. In this study, a design process regarding the steel brush, which has been employed for multi-axial compression test to reduce the frictional restraint along the specimen/loading platen interface, is introduced. The individual brushes are regarded as a simple column and beam to calculate the cross-sectional size and length of the brushes in consideration of the buckling capacity and the allowable deflection.

• Journal of Ocean Engineering and Technology
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• v.25 no.6
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• pp.66-71
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• 2011

Recently, the production of shipbuilding and offshore plant industries, with a trend toward large structures, has led to an increased use of high strength ultra-thick plates. The use of ultra-thick plates increases the welding tasks, and the welding process generates distortion and residual stress in the weldment because of the rapid heating and cooling. Welding distortion and residual stress in the welded structure resulte in many troubles such as deformation and life deterioration. In particular, the welding residual stress has an important effect on welding deformation, fatigue, buckling strength, brittleness, etc. The purpose of this study was to evaluate the residual stress at a multi-pass weldment using an experimental method for EH36 high-tension steel. In this experimental method, AIS3000 was used to measure the residual stress of a welded part, HAZ, and base metal; EPMA and XRD were used to study the material properties.