• Journal of Ocean Engineering and Technology
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• v.9 no.2
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• pp.20-29
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• 1995

When structures are constructed by welding, structural elements are always accompained by welding residual stress and deformation. Therefore, when the rigidity and strength of the welded structures is considered, it is very important to have sufficient information about the effect of initial deflection and welding residual stress on them. In this paper, the square plates with welding residual stress under compression are dealt with; First, heat conduction and thermal elastic-plastic problems are analyzed by finite element method using 4-node isoparametric elements for assessment on the ultimate strength of welding joint. Later, the ultimate strength of welding joint is assessed by examining the effect of changed type of loading. The specimens are 500{\times}$500mm(a/b=1) and 750{\times}$500mm(a/b=1.5) rectangular plates of whichthicknesses is 9.0mm and simply supported plates getting axiul load in each direction.

• Speech Sciences
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• v.9 no.4
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• pp.143-148
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• 2002

This study examined the foreign accent of Korean speakers of English concerning vowel length and utterance position. It then attempts to explain the foreign accent of Koreans when they speak English. The method was to measure the sentence-initial and sentence-final vowels as spoken by Koreans. I chose these two positions, sentence-initial and sentence-final, in order to know if Korean speakers of English, compared with native English speakers, show a difference in sentence stress. I chose English diphthongs, because most Koreans have difficulty pronouncing these sounds. I found that Korean speakers of English as a second language do not know English sentence stress patterns and show a foreign accent, especially when using diphthongs.

• Journal of the Korean Society of Safety
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• v.29 no.3
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• pp.136-142
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• 2014

Recently a new version of PRO-LOCA program was released. Using the program, failure probability of pipes can be evaluated considering fatigue and/or stress corrosion crack growth and the effects of various parameters on the integrity of pipes in nuclear power plants can be evaluated quantitatively. The analysis results can be used to establish an inspection plan and to examine the effects of important parameters in a maintenance plan. In this study, sensitivity analyses were performed using the program for several important parameters including sampling method, initial crack size, number of initial fabrication flaws, operation temperature, inspection interval, operation temperature and nominal applied bending stress. The effect of parameters on the leak and rupture probability of pipes was evaluated due to fatigue or stress corrosion crack growth.

• Transactions of Materials Processing
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• v.29 no.6
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• pp.316-322
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• 2020

The flow stress curve is usually determined via uniaxial tensile or simple compression test. However, the flow stress curve up to high strain cannot be obtained using these two tests. This study presents a simple method for obtaining the flow stress curve up to high strain via FE analysis, a simple compression test, and an indentation test. In order to draw the flow stress curve up to high strain, the indentation test was carried out with the pre-stained specimen using the simple compression test. The flow stress curve of Al6110 was evaluated up to high strain using the proposed method, and the result was compared with the flow stress curve of the uniaxial tensile test of the initial material.

• Journal of the Korea Concrete Institute
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• v.12 no.3
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• pp.31-37
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• 2000

When a crack is produced in a concrete structure, a micro crack zone of fracture process zone (FPZ) appears at the crack tip. To investigate the behaviour of this the micro crack zone, nonlinear fracture mechanics (NLFM) must be applied. However, when a massive concrete structure such as a concrete gravity dam is considered, the micro crack zone can be neglected and the structure can be assumed to have linear elastic fracture mechanics (LEFM) behaviour. This study is divided into two main topics : (1) Calculating stress intensity factor (SIF) at the crack tip by surface integral method and (2) Investigating the propagation of the initial crack. If the initial crack propagates, the angle of the propagation is calculated by using maximum circumferential tensile strength theory. This study, also, contains the effects of body forces and water pressures on the crack face.

• Structural Engineering and Mechanics
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• v.31 no.4
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• pp.407-421
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• 2009

The present paper addresses the optimal design of composite laminates with the aim of minimizing free-edge delamination stresses. A technique involving the application of particle swarm optimization (PSO) integrated with FEM was developed for the optimization. Optimization was also conducted with the zero-order method (ZOM) included in ANSYS. The semi-analytical method, which provides an approximation of the interlaminar normal stress of laminates under in-plane load, was used to partially validate the optimization results. It was found that optimal results based on ZOM are sensitive to the starting design points, and an unsuitable initial design set will lead to a result far from global solution. By contrast, the proposed method can find the global optimal solution regardless of initial designs, and the solutions were better than those obtained by ZOM in all the cases investigated.

• Structural Engineering and Mechanics
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• v.59 no.5
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• pp.841-852
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• 2016

The present paper is concerned with the investigation of propagation of thermoelastic media, the finite difference technique is used to obtain the solution for the uncoupled dynamic thermoelastic stress problem in a non-homogeneous orthrotropc thick cylindrical shell. In implementing the method, the linear dynamic thermoelasticity equations are used with the appropriate boundary and initial conditions. Thermal shock stress becomes of significant magnitude due to stress wave propagation which is initiated at the boundaries by sudden thermal loading. Numerical results have been given and illustrated graphically in each case considered. The presented results indicate that the effect of inhomogeneity is very pronounced.

• Journal of the Korean Geotechnical Society
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• v.29 no.8
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• pp.15-25
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• 2013

In order to examine the unsaturated shear strength characteristics of compacted weathered gneiss soils, the constant water content compression (CWCC) test was carried out. Specimens were made by static compaction under two densities conditions. The shear behavior in accordance with an initial suction obtained by varying initial degrees of saturation was evaluated. The suction could be directly measured by the use of the ceramic disk and the pore-water pressure transducer. The results of the peak shear strength from the CWCC test were examined using the relationship with Mp line from triaxial test under the saturated state, that is, by means of the suction stress which was calculated using the measured suction. In addition, the applicability of the suctions stress to the unsaturated shear behaviour of compacted weathered gneiss soils was discussed by applying Suction stress-SWCC Method (SSM).

• Korean journal of food and cookery science
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• v.5 no.1
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• pp.49-52
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• 1989

Stress relaxation tests with different percent deformation were performed for crude and refined starch gels of acorn. With no relation to percent deformation, refined starch gel had higher initial stress ($\sigma_e$) and lower equilibrium stress ($\sigma_e$) than crude starch gel. But the ratio of equilibrium stress to initial stress ($\sigma_e$/$\sigma_o$) was minimum at 60 percent deformation. The analysis of relaxation curves by successive residual method revealed that the rheological behavior of acorn starch gels could be expressed by generalized Maxwell model. The element numbers of models for crude and refined starch gel were 7-element and 5-element at 60 percent deformation, and 5-element and 3-element at 45 percent deformation, respectively.

• Computers and Concrete
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• v.15 no.1
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• pp.55-71
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• 2015

This paper presents a novel harmony search (HS)-based data-driven single input rule modules (SIRMs)-connected fuzzy inference system (FIS) for the prediction of stress in externally prestressed tendon. The proposed method attempts to extract causal relationship of a system from an input-output pairs of data even without knowing the complete physical knowledge of the system. The monotonicity property is then exploited as an additional qualitative information to obtain a meaningful SIRMs-connected FIS model. This method is then validated using results from test data of the literature. Several parameters, such as initial tendon depth to beam ratio; deviators spacing to the initial tendon depth ratio; and distance of a concentrated load from the nearest support to the effective beam span are considered. A computer simulation for estimating the stress increase in externally prestressed tendon, ${\Delta}f_{ps}$, is then reported. The contributions of this paper is two folds; (i) it contributes towards a new monotonicity-preserving data-driven FIS model in fuzzy modeling and (ii) it provides a novel solution for estimating the ${\Delta}f_{ps}$ even without a complete physical knowledge of unbonded tendons.