• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 1999.10a
• /
• pp.265-272
• /
• 1999

This stability of a plate structure is very crucial problem which results in wrinkle and bucking. In this study, the effect of the pattern of spot-welding points of the two rectangular plates on the compressive and shear bucking load is studied with respect to the thickness, aspect ratio of plates and number of welding spots. Buckling coefficient of the plate not welded was compared with that of two plates with various thickness to extract the effect of thickness. The effect of number of welding spots are studied in two directions, longitudinal and transverse directions. The conclusions obtained were that the reinforcement effect was maximized when the aspect ratio was close to 1.75 at compressive load condition and that the effect of number of welding spots in transverse direction was larger than that in longitudinal direction at shearing load condition.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2003.03a
• /
• pp.409-414
• /
• 2003

A multi-span bridge model that is fixed in longitudinal direction at a single pier can be very vulnerable to the earthquake ground motion in longitudinal direction. If the seismic load exceeds the capacity of the pier, it can be severely damaged. However, such incident can be prevented if piers of movable support share the seismic load as setting up seismic load transmitting device. This study is performed to investigate seismic performance of continuous bridge model with seismic load transmitting devices which is proposed newly. It is found that continuous bridge model system with device is more effective about displacement control and seismic performance.

• Steel and Composite Structures
• /
• v.46 no.6
• /
• pp.719-729
• /
• 2023

This paper studies electro-magneto-mechanical bending studying of the cylindrical panels based on shear deformation theory. The cylindrical panel is constrained with two simply-supported edges at longitudinal direction and two clamped boundary conditions at circumferential direction. The governing equations are derived based on the principle of virtual work in cylindrical coordinate system. Levy-type solution of the governing equations is derived to reduce two dimensional PDEs to a 2D ODEs. The reduced ordinary differential equation is solved using the Eigen-value Eigen-vector method for the clamped-clamped boundary condition. The electro-magneto-mechanical bending results are obtained to show that every displacement, rotation and electromagnetic potentials how change with changes of initial electromagnetic potentials and mechanical loads along longitudinal and circumferential directions.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2001.04a
• /
• pp.187-190
• /
• 2001

This study is concerned with the hydrodispersive characteristics of granite in Changwon area. A single-well injection/recovery tracer test was conducted to determine longitudinal dispersivity of the granite, using sodium chloride tracer The dispersivity values obtained from the injection phase are 0.48 m (for between PW-1 and OW-3) and 0.72 m (for between PW-1 and OW-4). That obtained from the recovery phase is 0.68 m. The result of the tracer test indicates that the anisotropy and heterogeneity of the granite and the direction of flow.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.5
• /
• pp.1150-1157
• /
• 1988

Two-dimensional turbulent plane jet which is under the pressure gradient in the transverse direction is studied numerically. Full Navier-Stokes equations are used to correctly account for the pressure variation in the transverse direction. Using the standard k-.epsilon. turbulence model as a closure relationship, a time marching procedure gives the velocity field. The temperature fields are obtained for two different cases : (1) Hot jet is issued into the cold still air, and (2) Hot jet is issued into the surrounding across which exists a temperature difference. The velocity and temperature fields along with other flow and heat-transfer characteristics for two different pressure gradients are presented. A simple formula that relates the jet trajectory to the pressure gradient is also proposed. The mass flux in the longitudinal direction and the jet halfwidth seem insensitive to the pressure gradient. However, the pressure gradient increases the heat flux in the longitudinal direction as well as in the transverse direction.

• Structural Engineering and Mechanics
• /
• v.30 no.3
• /
• pp.369-382
• /
• 2008

An oscillator of two lumped masses linked through a vertical spring moves forward in the horizontal direction, initially at a certain height, over a horizontal Euler beam and descends on it due to its own weight. Vibration of the beam and the oscillator is excited at the onset of the ensuing impact. The impact produced by the descending oscillator is assumed to be either perfectly elastic or perfectly plastic. If the impact is perfectly elastic, the oscillator bounces off and hits the beam a number of times as it moves forward in the longitudinal direction of the beam, exchanging its dynamics with that of the beam. If the impact is perfectly plastic, the oscillator (initially) sticks to the beam after its first impact and then may separate and reattach to the beam as it moves along the beam. Further events of separation and reattachment may follow. This interesting and seemingly simple dynamic problem actually displays rather complicated dynamic behaviour and has never been studied in the past. It is found through simulated numerical examples that multiple events of separation and impact can take place for both perfectly elastic impact and perfectly plastic impact (though more of these in the case of perfectly elastic impact) and the dynamic response of the oscillator and the beam looks noisy when there is an event of impact because impact excites higher-frequency components. For the perfectly plastic impact, the oscillator can experience multiple events of consecutive separation from the beam and subsequent reattachment to it.

• Structural Engineering and Mechanics
• /
• v.18 no.2
• /
• pp.247-262
• /
• 2004

In the earlier application of the spline finite strip method(FSM), the uniform B3-spline functions were used in the longitudinal direction while the conventional interpolation functions were used in the transverse direction to construct the displacement filed in a strip. To overcome the shortcoming of the uniform B3-spline, non-periodic B-spline was developed as the displacement function. The use of non-periodic B3-spline function requires no tangential vectors at both ends to interpolate the geometry of shell and the Kronecker delta property is also satisfied at the end boundaries. Recently, non-periodic spline FSM which was modified to have a multiple knots at the boundary was developed for the shell analysis and applied to the analysis of bridges. In the formulation of a non-symmetric spline finite strip method, the concepts of non-periodic B3-spline and a stress-resultant finite strip with drilling degrees of freedom for a shell are used. The introduction of non-symmetrically spaced knots in the longitudinal direction allows the selective local refinement to improve the accuracy of solution at the connections or at the location of concentrated load. A number of numerical tests were performed to prove the accuracy and efficiency of the present study.

• Structural Engineering and Mechanics
• /
• v.87 no.2
• /
• pp.107-116
• /
• 2023

The three-dimensional Hashin criterion and user subroutine VUMAT were used to simulate the damage in the composite layer, and the secondary stress criterion was used to simulate the interlayer failure of the cohesive element of the bonding layer and the propagation characteristics under the layer. The results showed that when the shear stress wave (shear wave) propagates on the surface of the laminate, the stress wave attenuation along the fiber strength direction is small, and thus producing a large stress profile. When the compressive stress wave (longitudinal wave) is transmitted between the layers, it is reflected immediately instead of being transmitted immediately. This phenomenon occurs only when the energy has accumulated to a certain degree between the layers. The transmission of longitudinal waves is related to the thickness and the layer orientation. Along the symmetry across the thickness direction, the greater is the stress amplitude along the layer direction. Based on the detailed investigation on the impact on various laminated composites carried out in this paper, the propagation characteristics of stress waves, the damage and the destruction of laminates can be explained from the perspective of stress waves and a reasonable layering sequence of the composite can be designed against damage and failure from low velocity impact.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.18 no.6
• /
• pp.545-556
• /
• 2016

If a back analysis is used in various measurement information for the estimation of an operating subsea tunnel safety, it is possible to obtain the results within efficient error rate. With such a commercial geotechnical analysis program as FLAC3D, back analysis is performed with a DEA which was validated in previous studies. However, there is a problem that is relatively a time-consuming analysis. For this reason, beam-spring model-based FEM solver which takes shorter relative analysis time, was developed by Python language, and then combined with the built-DEA. In order to consider the assessment of safety of an operation tunnel near real-time, a program for longitudinal direction tunnel was developed due to its relative easy development for analysis solver engine.

• Journal of the Korean Magnetics Society
• /
• v.18 no.1
• /
• pp.28-31
• /
• 2008

We studied the effect of easy magnetization axis orientation with respect to the strip direction by measuring the magnetoresistance(MR), the magneto-optic Kerr effect(MOKE), and real-time domain evolution. The five strips were patterned on a single chip with the easy axis orientation of each strip relative to the longitudinal direction by around $0^{\circ}$, $18^{\circ}$, $36^{\circ}$, $54^{\circ}$ and $72^{\circ}$, respectively. The overall shape of field dependent MR was mostly governed by the anisotropy magnetoresistnace. The relative change of the longitudinal MR was significantly increased with increasing angle between the easy axis and strip direction, whereas, the transverse MR variation rate was decreased with increasing angle. Several MR steps were observed during the magnetization reversal, and the simultaneous measurement of the MOKE and the domain images identified that the MR steps were associated with evolution of the oppositely directed magnetic domain.