• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.11
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• pp.2823-2827
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• 2000

The dynamic photoelasticity with the aid of Cranz-Shardin type high speed camera system is utilized to record the dynamically propagating behavior of an interface crack. This paper investigates determined the effects of the hole (exited on the path of the crack propagation) on the crack propagation behavior by comparing the experiment isochromatic fringes to the theoretical stress fields.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.2 s.72
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• pp.151-160
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• 2006

In this study, we propose a new efficient 2-noded hybrid-mixed element for curved beam vibrationshaving a uniform and non-uniform cross section. The present element considering transverse shear strain is based on Hellinger-Reissner variational principle and introduces additional nodeless degrees for displacement field interpolation in order to enhance the numerical performance. The stress parameters are eliminated by the stationary condition and then the nodeless degrees are condensed out by the Guyan reduction. In the performance evaluation process of the present field-consistent higher-order element, we carefully examine the effects of field consistency and the role of higher-order interpolation functions on the hybrid-mixed formulation. Several benchmark tests confirm e superior behavior of the present hybrid-mixed element for curved beam vibrations.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3A
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• pp.465-471
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• 2006

To describe hysteretic behavior of steel structures under dynamic loading such as earthquake, the dynamic cyclic plasticity model considering stress-strain relationship and characteristics of used steel materials under static-dynamic deforming is required. In this paper, mechanical characteristics and stress-strain relationship of SM490 was clarified by carrying out static-dynamic monotonic and cyclic loading test. A dynamic cyclic plasticity model of SM490 was proposed based on the test results and applied 3-dimensional finite element analysis using finite deformation theory. An analytical method developed by the authors was verified validity and accuracy by comparing both analysis and test results. The comparison result shows that the analytical method developed by the authors can predict static-dynamic hysteretic behavior of steel structures with accuracy.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.3
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• pp.37-43
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• 1995

The procedure and the results of the full scale strain measurement of the long-range high-speed foil catamaran are described. The wave induced stresses at the center struts of the foils were measured during the sea trials in order to evaluate the hydrodynamic force acting on the foils and to verify the structural safety of the foil structures. From the statistical properties of the measured response of the stress, the most probable maximum values of the lift force and the stresses at the foils in service life of the ship are predicted and compared with the design parameters of the foils which were applied in the design of the subject ship. The available prediction processes of the measured stress are studied and the results of the applied processes are compared with each other.

• Journal of the Korean Geotechnical Society
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• v.33 no.12
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• pp.141-150
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• 2017

Geosynthetics are generally utilized to restrain the leakage of leachate and other contaminants during the construction of offshore waste landfill. Therefore, geosynthetic-soil interface is formed inevitably. In this study, 2 dimensional numerical analysis is performed to assess the dynamic behaviour of the offshore waste landfill including geosynthetic-soil interface. Offshore waste landfill can be divided into rubble mound revetment and retaining wall types and analyzed on each type. Effective stress analysis is conducted to consider the variation of pore water pressure and axial force and shear displacement of the interface are compared based on the characteristics of seismic frequency. Consequently, retaining wall type demonstrates more stable behavior against liquefaction potential and favorable forces and shear displacement.

• The Korean Journal of Rheology
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• v.11 no.2
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• pp.82-90
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• 1999

Electrorheological(ER) fluid is a material that shows the dramatic change of rheological properties under an electric field and responds reversibly in a few milliseconds. ER fluid's response to an electric field along with its fast switching capability allows ER devices to be precisely controlled. The real application with ER fluid, however, has many limitations to be overcome; temperature fluctuation, moisture, dust, aggregation, precipitation, and low yield stress, for example. The magnitude and the characteristics of yield stress of ER fluid plays an important role in practical applications. In this research, a dynamic simulation on the squeezing flow of the ER fluid was carried out. Numerical simulation on isolated chains was performed to find out the effect of hydrodynamic and electrostatic force depending on the chain location, the squeezing rate, and the chain structure. Suspension model that is composed of a large number of particles was also investigated. The increase of normal stresses as well as the existence of a yield stress at an earlier stage could be observed, and the effective control of the normal stresses could be achieved at an optimal condition of the hydrodynamic force and the electrostatic force.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.5
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• pp.9-14
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• 2002

A higher order zig-zag plate theory is developed to accurately predict fully coupled mechanical, thermal, and electric behaviors. Both the in-plane displacement and temperature fields through the thickness are constructed by superimposing linear zig-zag field to the smooth globally cubic varying field. Smooth parabolic distribution through the thickness is assumed in the transverse deflection in order to consider transverse normal deformation. Linear zig-zag form is adopted in the electric field. The layer-dependent degrees of freedom of displacement and temperature fields are expressed in tern-is of reference primary degrees of freedom by applying interface continuity conditions as well as bounding surface conditions of transverse shear stresses and transverse heat flux. The numerical examples of coupled and uncoupled analysis demonstrate the accuracy and efficiency of the present theory. The present theory is suitable for the predictions of fully coupled behaviors of thick smart composite plate under mechanical, thermal, and electric loadings combined.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.3-8
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• 2001

Dynamic stress intensity factors (DSIFs) are obtained when a crack propagates with constant velocity in rectangular functionally gradient materials (FGMs) under dynamic mode III load. To obtain the dynamic stress intensity factors, it is used the general stress and displacement fields of FGMs for propagating crack and the boundary collocation method (BCM). The stress intensity factors and energy release rates are the greatest in the increasing properties $(\xi>0)$, next constant properties $(\x=0)$ and decreasing properties $(\xi<0)$ under constant crack tip properties and crack tip speed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.2
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• pp.165-172
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• 2003

In this study, a new and efficient harmonic axisymmetric shell element for static and dynamic analysis Is proposed. The present element considering shear strain is based on a modified mixed variational principle in which the independent unknowns are only the Quantities prescribable at the shell edges. Unlike existing hybrid-mixed axisymmetric shell elements, the present element introduces additional nodeless degrees for displacement field Interpolation In order to enhance the numerical performance. The stress parameters are eliminated by the stationary condition and the nodeless degrees are condensed out by the Guyan reduction. Through several numerical examples, the hybrid-miked shell element with the additional nodeless degrees and the consistent stress parameters is shown to be efficient and yield very accurate results for static and vibration analysis.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.6
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• pp.55-63
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• 2008

This paper presents a seismic analysis technique for a 3D soil-structure interaction system in a frequency domain, based on the finite element formulation incorporating frequency-dependent infinite elements for the far field soil region. Earthquake input motions are regarded as traveling P, SV and SH waves which are incident vertically from the far-field soil region, and then equivalent earthquake forces are calculated using impedances of infinite soil by dynamic infinite elements and traction and displacement from free field response analysis. For verification and application, seismic response analyses are carried out for a multi-layered soil medium without structure and a typical nuclear power plant in consideration of soil-structure interaction. The results are compared with the free field response using a one-dimensional analytic solution, and a dynamic response of an example structure from another SSI package.