• Transactions of Materials Processing
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• v.19 no.6
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• pp.344-351
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• 2010

This paper presents a precision on-line model for the prediction of the roll force and tension distributions across the strip in hot strip rolling. The approach is based on an approximate 3-D theory of rolling, and in particular, considers the effect of pre-deformation of the strip, which occurs near the roll entrance before the strip enters the bite zone. The prediction accuracy of the proposed model is examined through comparison with the predictions from the 3-D finite element models.

• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.200-205
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• 2011

Axial and radial distributions of bubble holdup were investigated in a slurry bubble column with pilot plant scale(D=1.0 m). Effects of gas velocity, surface tension of continuous liquid medium and solid fraction in the slurry phase on the axial and radial distributions of bubble holdup were examined. The bubble holdup decreased with increasing radial dimensionless distance from the center of the column, while it increased with increasing dimensionless distance in the axial direction from the distributor, in all the cases studied. The radial non-uniformity of bubble holdup increased with increasing gas velocity but decreasing surface tension of liquid medium, while it was not dependent upon the solid fraction in the slurry phase. The axial non-uniformity of bubble holdup increased with increasing gas velocity, but it does not change considerably with variations of liquid surface tension or solid fraction in the slurry phase . The axial and radial distributions of bubble holdup were well correlated in terms of operating variables within this experimental conditions.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.1
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• pp.225-232
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• 2005

The paper presented results of the strength distributions and tension failure behaviors of splices subjected to tension forces. The bolting patterns in the tension splices are regular and staggered patterns in the research. The finite element analyses were carried out to examine the experimental results and evaluated the stress distribution patterns. The yield stresses, maximum tension stresses, stress distribution ratios, and effective net areas were analyzed through the tension experiments.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.8
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• pp.138-148
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• 1999

Thermal deformations of tension mask under localized heating are analyzed using finite element method and electron beam landing shifts are predicted by the analysis results. In CRT, electron beam landing shifts due to thermal deformations of the tension mask make the color purity of screen worse. In order to get the final results of thermal deformations, firstly the tension processes of the mask and following welding processes between the tensional mask and rail must be analyzed sequentially. And then, nonlinear transient thermo-elastic finite element analysis is performed on every part inside CRT including tension mask, wherein thermal radiation is a main heat transfer mechanism. Because the tension mask has numerous slits, the effective thermal conductivity and effective and effective elastic modulus is calculated, and the tension mask is modeled as a shell without slits. From the displacement results of tension mask, electron beam landing shifts is calculated directly. Experiments are performed to confirm our analysis results. Temperature distributions and beam landing shifts of tension mask are measured and the results are in good agreement with those of analyses.

• Steel and Composite Structures
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• v.18 no.5
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• pp.1103-1117
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• 2015

It is known that material properties, connection quality and manufacturing methods are among the important factors directly affecting the behavior of steel connections and hence steel structures. The possible performance differences between a fabricated connection and its computer model may cause critical design problems for steel structures. Achieving a reliable design depends, however, on how accurately the material properties and relevant constitutive models are considered to characterize the behavior of structures. Conventionally, the stress and strain fields in structural steel connections are calculated using the finite elements method with assumed material properties and constitutive models. Because the conventional strain gages allow the measurement of deformation only at one point and direction for specific time duration, it is not possible to determine the general characteristics of stress-strain distributions in connections after the laboratory performance tests. In this study, a new method is introduced to measure displacement distribution of simple steel welded connections under tension tests. The method is based on analyzing digital images of connection specimens taken periodically during the laboratory tension test. By using this method, displacement distribution of steel connections can be calculated with an acceptable precision for the tested connections. Calculated displacements based on the digital image correlation method are compared with those calculated using the finite elements method.

• Journal of Mechanical Science and Technology
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• v.16 no.11
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• pp.1477-1484
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• 2002

Various characteristics of a thin liquid film in its vapor-phase are investigated using the molecular dynamics technique. Local distributions of the temperature, density, normal and tangential pressure components, and stress are calculated for various film thicknesses and temperature levels. Distributions of local stresses change considerably with respect to film thicknesses, and interracial regions on both sides of the film start to overlap with each other as the film becomes thinner. Integration of the local stresses, i.e., the surface tension, however, does not vary much regardless of the interfacial overlap. The minimum thickness of a liquid film before rupturing is estimated with respect to the calculation domain sizes and is compared with a simple theoretical relation.

• The korean journal of orthodontics
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• v.11 no.1
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• pp.17-23
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• 1981

This experiment was performed to investigate the response of inorganic substances in alveolar bone in relation to the experimental tooth movement. Right canine in maxillary jaw was tipped in cats by coil springs generating 80 gm. force, in mandibular jaw, the force was 100 gm. force. Cats were divided into five groups and orthodontically treated for one hour, 1, 7, 14 and 28 days, respectively. Alveolar bone samples were obtained from tension and compression sites as well as from contralateral control sites. The level of calcium of alveolar bone was determined by atomic absorption spectrophotometry and inorganic phosphorus was measured by spectrophotometry. The results obtained were as follows: 1. In tension and compression site of maxillary alveolar bone, calcium levels were decreased at 1, 7 and 14 days, but recovered at 28 days. 2. The levels of inorganic phosphorus in compression site of maxillary alveolar bone had little change but in tension site of maxillary alveolar bone , phosphorous levels were decreased, 3. Calcium levels in tension and compression site of mandibular alveolar bone were decreased, especially at 28 days. 4. In tension and compression site of mandibular alveolar bone, inorganic phosphorus were slightly decreased from 1 day.

• Journal of the Korean Wood Science and Technology
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• v.19 no.1
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• pp.64-70
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• 1991

In order ot obtain the information on wood quality of the Populus nigra $\times$ maximowiczii the distributions of crystalliferous substancess, ty loses and tension woods were examined through light microscopy or scanning electron microscopy. 1. The crystalliferous subtance, presumably calcium oxalate. partially occurred in vessel elements of heartwood, and sporadically in ray parenchyma, but not in the wood fibers The types of crystalliferous subtances were mainly crystal sand, $2-3{\mu}m$ in diameter. 2. The tyloses arranged in a ladder-like series were sporadically formed in the vessel elements of heartwood. 3. Although the woods were cut from the straightly grown stem without any evident disorientation with respect to gravitational axis, single or group of gelatinous fibers were irregularly distributed among normal wood fibers.

• Journal of Mechanical Science and Technology
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• v.18 no.1
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• pp.106-113
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• 2004

Recently, a new issue in designing spot welded structures such as automobile and train car bodies is to predict an economical fatigue design criterion. One of the most typical and traditional methods is to use a ΔP-N$\sub$f/ curve. However, since the fatigue data on the ΔP-N$\sub$f/ curve vary according to the welding conditions, materials, geometry of joint and fatigue loading conditions, it is necessary to perform the additional fatigue tests for determining a new fatigue design criterion of spot-welded lap joint having specific dimension and geometry. In this study, the stress distributions around spot welds of various spot welded lap joints such as in-plane bending type (IB type), tension shea. type (TS type) and cross tension type (CT type) were numerically analyzed. Using these results, the ΔP-N$\sub$f/ curves Previously obtained from the fatigue tests for each type were rearranged into the Δ$\sigma$-N$\sub$f/ relations with the maximum stresses at the nugget edge of the spot weld.

• Structural Engineering and Mechanics
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• v.82 no.5
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• pp.611-628
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• 2022

Energy-dissipative rocking (EDR) columns are a class of seismic mitigation device capable of dissipating seismic energy and preventing weak-story failure of moment resisting frames (MRFs). An EDR consists of two hinge-supported steel columns interconnected by steel dampers along its height. Under earthquakes, the input seismic energy can be dissipated by plastic energy of the steel dampers in the EDR column. However, the unrecoverable plastic deformation of steel dampers generally results in residual drifts in the structural system. This paper presents a proof-of-concept study on an innovative device, namely self-centring energy-dissipative rocking (SC-EDR) column, aiming at enabling self-centring capability of the EDR column by installing a set of shape memory alloy (SMA) tension braces. The working mechanism of the SC-EDR column is presented in detail, and the feasibility of the new device is carefully examined via experimental and numerical studies considering the parameters of the SMA bar diameter and the steel damper plate thickness. The seismic responses including load carrying capacities, stress distributions, base rocking behaviour, source of residual deformation, and energy dissipation are discussed in detail. A rational combination of the steel damper and the SMA tension braces can achieve excellent energy dissipation and self-centring performance.