• Steel and Composite Structures
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• v.38 no.4
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• pp.355-363
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• 2021

The present paper attempts to investigate the propagation of plane waves in an isotropic elastic medium under the effect of initial stress and temperature-dependent properties. The modulus of elasticity is taken as a linear function of the reference temperature. The formulation is applied under the thermoelasticity theory with dual-phase-lag; the normal mode analysis is used to obtain the expressions for the displacement components, the temperature, the stress, and the strain components. Numerical results for the field quantities are given in the physical domain and illustrated graphically. Comparisons are made with the results predicted by different theories (Lord-Shulman theory, the classical coupled theory of thermoelasticity and the dual-phase-lag model) in the absence and presence of the initial stress as well as the case where the modulus of elasticity is independent of temperature.

• Journal of Mechanical Science and Technology
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• v.18 no.9
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• pp.1500-1511
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• 2004

In this paper, the anti-plane transient response of a central crack normal to the interface between a piezoelectric ceramics and two same elastic materials is considered. The assumed crack surfaces are permeable. By virtue of integral transform methods, the electro elastic mixed boundary problems are formulated as two set of dual integral equations, which, in turn, are reduced to a Fredholm integral equation of the second kind in the Laplace transform domain. Time domain solutions are obtained by inverting Laplace domain solutions using a numerical scheme. Numerical values on the quasi-static stress intensity factor and the dynamic energy release rate are presented to show the dependences upon the geometry, material combination, electromechanical coupling coefficient and electric field.

• Geotechnical Engineering
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• v.5 no.2
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• pp.57-77
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• 1989

This paper describes the design and construction aspects of time-dependent deformation test apparatus for slut.oiling rocks and presents the test results obtained using these apparatus. These tests are modified semi-confined swell test, swell test under uniaxial tension and swell test under biaxial stress. These apparatus measure the time.dependent deformations in three orthogonal directions of the test specimen under simplified field stress conditions. The test results obtained from these test apparatus for the last several years show that these apparatus have performed satisfactorily. The test results show that the time-dependent deformation behaviour of the Queenston shale is cross-anisotropic with higher swelling in the vertical direction (normal to bedding plane) than in horizontal direction (parallel to bedding plane) under free swell condition. The applied stress in one direction suppresses the swelling deformation in that direction as well as that in the orthogonal directions.

• Composites Research
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• v.26 no.4
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• pp.235-244
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• 2013

A volume integral equation method (VIEM) is introduced for the solution of elastostatic problems in an unbounded isotropic elastic solid containing multiple isotropic elliptical fibers of arbitrary orientation subject to uniform stress at infinity. The fibers are assumed to be long parallel elliptical cylinders composed of isotropic elastic material perfectly bonded to the isotropic matrix. The solid is assumed to be under plane strain on the plane normal to the cylinders. A detailed analysis of the stress field at the matrix-fiber interface for square and hexagonal packing of the fibers is carried out for different values of the number, orientation angles and concentration of the elliptical fibers. The accuracy and efficiency of the method are examined through comparison with results obtained from analytical and finite element methods.

• Steel and Composite Structures
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• v.28 no.3
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• pp.319-329
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• 2018

The field around additional cutout of the floor beam web in orthotropic bridge deck was subjected to high stress concentration, especially the weld toe between floor beam and U shaped rib and the free edge of the additional cutout. Based on different considerations, different geometrical parameters of additional cutout were proposed in European, American and Japanese specifications, and there remained remarkable differences among them. In this study, considering influence of out-of-plane deformation of floor beam web and U shaped rib, parameter analysis for additional cutout under typical load cases was performed by fine finite element method. The influence of additional cutout shape and height to the stress distribution around the additional cutout were investigated and analyzed. Meanwhile, the static and fatigue test on this structure details was carried out. The stress distribution was consistent with the finite element analysis results. The fatigue property for additional cutout height of 95mm was slightly better than that of 61.5 mm.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.1
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• pp.67-77
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• 2014

In this study, Explicit Algebraic Reynolds Stress Model (EARSM) which is based on the existing ${\kappa}-{\omega}$ model has been applied to the flow field analysis around ship hulls. Existing transport equations for the turbulent kinetic energy and the dissipation rate are used in almost the same form and anisotropy terms of Reynolds stresses are newly considered. The well-known KVLCC2 and KCS hull forms are selected as validation cases, which were also used in 2010 Workshop on CFD in Ship Hydrodynamics. In case of KVLCC2 double model, comparison of mean velocity distribution, turbulent kinetic energy, and Reynolds stresses near the propeller plane has been carried out and wave elevation and wave profiles have been additionally studied for KCS and KVLCC2 with free surface models. Some improved results for mean velocity distribution at the propeller plane have been obtained while there is little change in free surface wave profiles.

• Journal of the Korean earth science society
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• v.35 no.5
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• pp.354-361
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• 2014

Fault plane solutions in North Korea and the northern part of the Yellow Sea ($37.5^{\circ}N-40.5^{\circ}N$, $124.5^{\circ}E-128.5^{\circ}E$) was studied for the earthquakes that occurred from November, 2008 to May, 2013. The analysis was based on the data collected from seismic networks in Korea and China. Fault plane solutions were obtained from P and SH wave polarities and SH/P amplitude ratioes. Most earthquakes exhibited predominantly strike-slip fault characteristics with NNE-SSW or WNW-ESE nodal planes. The P-axes trends are mainly NE-SW or ENE-WSW direction in the northern part of the Yellow Sea and inland area of North Korea except some areas in the Hwanghae province. Fault plane solutions and main axis of stress field in the study region were similar to those observed in the southern part of the Korean Peninsula.

• Tunnel and Underground Space
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• v.14 no.2
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• pp.142-153
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• 2004

To investigate the influence of the rock mass inhomogeneity caused by layer geometry on the regional stress distribution the cuboid models considering a homogenous rock mass, inhomogeneous rock mass with plane layers and with uneven layers were analyzed and discussed. It was confirmed that the structure and existence of layers in rock mass affected the regional stress distribution. An approach based on an inverse analysis of the measured local stresses and the 3D finite element analysis was suggested, and used to estimate the regional stress field of the homogeneous and inhomogeneous models, which consist of the surface geometry of ground and both the surface and layer geometry respectively. Additionally, the approach of the regional stress considering the layer geometry in the rock mass was verified to estimate the regional stress field for a site.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.4
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• pp.494-502
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• 2003

The near-tip field of mode-I dynamic cracks steadily propagating in a strain softening material is investigated under plane strain conditions. The material is assumed to be incompressible and its deformation obeys the $J_2$ flow theory of plasticity. A power-law stress-strain relation with strain softening is adopted to account for the damage behavior of materials near the dynamic crack tip. By assuming that the stresses and strain have the same singularity at the crack tip. this paper obtains a fully continuous dynamic crack-tip field in the damage region. Results show that the stress and strain components the same logarithmic singularity of (In(R/r))$\delta$, and the angular variations of filed quantities are identical to those corresponding to the dynamic cracks in the elastic-perfectly plastic material.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.405-410
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• 2000

Generally, it is known that the reduced integration, modified shape function anisoparametric and non-conforming element can minimize the error induced by stiffness locking phenomenon in the finite element analysis. In this study, new anisoparametric curved beam elements are introduced by using different shape functions in each displacement field. When these shape functions are substitute for functional, we can expect that the undulate stress patterns are not appeared or minimized because there is no unmatched coefficient in the constrained energy equation. As a result of numerical test, the undulate stress patterns are disappeared, and displacement and stress are coincide with the exact solutions.