• Computational Structural Engineering
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• v.6 no.4
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• pp.83-88
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• 1993

A time-discontinuous Galerkin method based upon using a finite element formulation in time has evolved. This method, working from the differential equation viewpoint, is different from those which have been generally used. They admit discontinuities with respect to the time variable at each time step. In particular, the elements can be chosen arbitrarily at each time step with no connection with the elements corresponding to the previous step. Interpolation functions and weighting functions are taken to be discontinuous across inter-element boundaries. These methods lead to a unconditional stable higher-order accurate ordinary differential equation solver.

• 한국전산유체공학회:학술대회논문집
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• 2009.11a
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• pp.223-227
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• 2009

In the present study, a least square weighted residual method and Taylor-Galerkin method were formulated and tested for the discretization of the two hyperbolic type equations of level set method; advection and reinitialization equations. The two approaches were compared by solving a time reversed vortex flow and three-dimensional broken dam flow by employing a four-step splitting finite element method for the solution of the incompressible Navier-Stokes equations. From the numerical experiments, it was shown that the least square method is more accurate and conservative than Taylor-Galerkin method and both methods are approximately first order accurate when both advection and reinitialization phase are involved in the evolution of free surface.

• Journal of Ocean Engineering and Technology
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• v.3 no.2
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• pp.570-570
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• 1989

The natural frequencies of a rectangular plate on non-homogeneous elastic foundations were obtained by using the Ritz method and Galerkin method. The results of both methods using the different type of trial functions were also compared. Furthermore, the effects of the variation of boundary conditions, the stiffness of the foundation spring, the dimension ratio of the plate were investigated. As a result, the Galerkin method can be used to obtain the accurate solution and can be effectively used to design the foundation bed.

• Journal of Ocean Engineering and Technology
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• v.3 no.2
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• pp.70-76
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• 1989

The natural frequencies of a rectangular plate on non-homogeneous elastic foundations were obtained by using the Ritz method and Galerkin method. The results of both methods using the different type of trial functions were also compared. Furthermore, the effects of the variation of boundary conditions, the stiffness of the foundation spring, the dimension ratio of the plate were investigated. As a result, the Galerkin method can be used to obtain the accurate solution and can be effectively used to design the foundation bed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.5
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• pp.939-951
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• 2002

We propose a new multiscale Galerkin method based on interpolation wavelets for two-dimensional Poisson's and plane elasticity problems. The major contributions of the present work are: 1) full multiresolution numerical analysis is carried out, 2) general boundaries are handled by a fictitious domain method without using a penalty term or the Lagrange multiplier, 3) no special integration rule is necessary unlike in the (bi-)orthogonal wavelet-based methods, and 4) an efficient adaptive scheme is easy to incorporate. Several benchmark-type problems are considered to show the effectiveness and the potentials of the present approach. is 1-2m/s and impact deformation of the electrode depends on the strain rate at that velocity, the dynamic behavior of the sinter-forged Cu-Cr is a key to investigate the impact characteristics of the electrodes. The dynamic response of the material at the high strain rate is obtained from the split Hopkinson pressure bar test using disc-type specimens. Experimental results from both quasi-static and dynamic compressive tests are Interpolated to construct the Johnson-Cook model as the constitutive relation that should be applied to simulation of the dynamic behavior of the electrodes. The impact characteristics of a vacuum interrupter are investigated with computer simulations by changing the value of five parameters such as the initial velocity of a movable electrode, the added mass of a movable electrode, the wipe spring constant, initial offset of a wipe spring and the virtual fixed spring constant.

• Journal of Advanced Navigation Technology
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• v.7 no.2
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• pp.180-190
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• 2003

By using accurate closed-form Green's functions obtained from real-axis integration method, the full-wave analysis of CPW discontinuities are performed in space domain. In solving MPIE(Mixed Potential Integral Equation), Galerkin's scheme is employed with the linear basis functions on the triangular elements in air-dielectric boundary. In the singular integral arising when the observation point and source point coincides, the surface integral is transformed into the line integral and the integral is evaluated by regular integration. By using the Green's function from the real-axis integration method, the discontinuities are characterized accurately.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.643-648
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• 2004

This paper is dedicated to the thermoelastic modeling and dynamic response of the rotating blades made of functionally graded ceramic-metal based materials. The blades modeled as non-uniform thin walled beams fixed at the hub with various selected values of setting angles and pre-twisted angles. In this study, the blade is rotating with a constant angular velocity and exposed to a steady temperature field as well as external excitation. Moreover, the effect of the temperature gradient through the blade thickness is considered. Material properties are graded in the thickness direction of the blade according to the volume fraction power law distribution. The numerical results highlight the effects of the volume fraction, temperature gradient, taper ratio, setting angle and pre-twisted angle on the dynamic response of bending-bending coupled beam characteristics are provided for the case of a biconvex cross section and pertinent conclusions are outlined.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.716-720
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• 2006

In order to examine the effect of constant excitation on nonlinear interactions in vibrating modes of circular plates, we added a constant term to a harmonic excitation. A two-degree-of freedom system is derived by using the Galerkin's procedure. The system is shown to have quadratic and cubic nonlinearities subjected to a harmonic excitation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.7 s.238
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• pp.976-982
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• 2005

This paper is dedicated to the thermoelastic modeling and dynamic response of the rotating blades made of functionally graded ceramic-metal based materials. The blades are modeled as non-uniform thin walled beams fixed at the hub with various selected values of setting angles and pre-twisted angles. In this study, the blade is rotating with a constant angular velocity and exposed to a steady temperature field as well as external excitation. Moreover, the effect of the temperature gradient through the blade thickness is considered. Material properties are graded in the thickness direction of the blade according to the volume fraction power law distribution. The numerical results highlight the effects of the volume fraction, temperature gradient, taper ratio, setting angle and pre-twisted angle on the dynamic response of bending-bending coupled beam characteristics and pertinent conclusions are outlined.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.169-170
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• 2014

In this study, a general strength concrete member is produced and its hydrothermal temperature is measured. It is intended to present the basic data for establishment of fire resistance performance assessment and review of safety against fire by comparing the data values of slab fire resistance experiment and the numerical analysis model. The value obtained by measuring the hydrothermal temperature of the concrete after heating the concrete designed to have general strength (30 Mpa) for 3 hours in accordance with the ISO 834 Heating Curve is compared with the value obtained from a thermal conduction analysis. As a result of the comparison, though there is a little difference, it is thought that fire behaviors can be predicted in the future if the movement of moisture and the added evaporation speed are taken into account.