• Journal of Korea Spatial Information System Society
• /
• v.5 no.1 s.9
• /
• pp.39-47
• /
• 2003

The purpose of this paper is to present the method of acquiring 3D GIS data using the statistical estimating methods of Well Log for balancing Seismic data. We use the reflection coefficients of seismic data to get the parameters for the reservoir characterization and we balance the reflection coefficients of seismic data using well log to increase the confidence of the estimated result. Well logs are required to balance the reflection coefficients at the point where seismic data are acquired. In this research, we discuss the geostatistical estimation methods and we applied these methods to real data. Kriging gives high weights to the close well logs, which means estimated results are mainly affected by close well log. High value of cross variograms gave big difference on cokriging result comparing to kriging results and low value of cross variogram gave little differences.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.45 no.2
• /
• pp.92-98
• /
• 2017

Porosity in polymer matrix composites generated during pyrolysis process affect the thermomechanical behavior of the composites. In this paper, multislice finite element models for the porous composite materials are developed, and poroelastic and failure analysis for these models are performed. In order to investigate the three-dimensional effects, finite element meshes are modeled considering different porosity(up to 0.5) and the number of slices (up to five). As a result, effective Young's moduli and poroelastic parameters exhibit the maximum differences of 74.0% and 442.1% with respect to porosity respectively, and 98.7% and 37.2% with respect to the number of slices. First and last failure strengths are decreased 88.2% and 90.0% with respect to porosity respectively, and 53.8% and 171.8% with respect to the number of slices.

• Elastomers and Composites
• /
• v.49 no.4
• /
• pp.267-274
• /
• 2014

Self vulcanizable blend system for magnetorheological elastomer (MRE) has been studied by dispersing magneto responsible particle (MRP) on elastomeric matrix. Chloroprene rubber was modified with maleic anhydride (MAH) using heat and pressure which is called dynamic maleation process. The optimum graft ratio of MAH was found at 10 phr contents and reaction temperature of $100^{\circ}C$. This could be confirmed by FT-IR analysis. Epoxided natural rubber (ENR) was blended with modified CR-g-MAH for self vulcanization. The optimum amounts of ENR was 30 wt% in terms of scorch time and curing rate. MRE was manufactured by electromagnetic equipment and orientation of MRE was confirmed by SEM. Finally, it was found that the tensile strength of anisotropic-MRE was higher than that of isotropic-MRE and the hardness was reverse.

• Elastomers and Composites
• /
• v.47 no.4
• /
• pp.318-328
• /
• 2012

In this study, the one-component curable polyurethane resin was manufactured using blocked isocyanate and hybrid technology. To prepare the one-component curable hybrid polyurethane, silica hybrids including hydroxyl group was synthesized, and the size, shape and distribution of hybrid particle in polyurethane resin were confirmed. Then the dissociation property, mechanical property and molding property of blocked isocyanate were investigated. The dissociation property of blocked isocyanate in one-component curable polyurethane became better as the heating temperature and treatment time increased. The synthesized silica hybrid had spherical appearance and size of 23~27 nm in diameter, and it was observed that the hybrid particles were homogeneously distributed in polyurethane structure. In the case of hybrid polyurethane, the mechanical property, anti-abrasion and thermal property were higher than those of general polyurethane, and it was observed that the mechanical property was maintained when the plasticizer was introduced.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.25 no.6
• /
• pp.95-102
• /
• 2021

Elastometic bearings using flexible rubber materials have recently been widely applied for seismic retrofit of bridges. However, due to various factors, the aging of the rubber material progresses, which causes the shear stiffness change of the bearing, which affects the seismic performance of the bridge. For natural rubber, accelerated heat aging test was performed with variables of heating temperatures and exposure time to analyze shear characteristics. As aging progresses (i.e. increase of temperature and exposure time), the maximum shear stress and shear strain decrease. Also, the shear stiffness is greatly increased at the same shear strain. This means that the rubber material is hardened, implying that the seismic performance of the elastomeric bearing becomes poor.

• Geophysics and Geophysical Exploration
• /
• v.27 no.3
• /
• pp.171-180
• /
• 2024

The processing of seismic data involves analyzing earthquake wave data to understand the internal structure and characteristics of the Earth, which requires high computational power. Recently, machine learning (ML) techniques have been introduced to address these challenges and have been utilized in various tasks such as noise reduction and velocity model construction. However, most studies have focused on specific seismic data processing tasks, limiting the full utilization of similar features and structures inherent in the datasets. In this study, we compared the efficacy of using receiver-wise time-series data ("receiver array") and synchronized receiver signals ("time array") from shotgathers for pretraining a Bidirectional Encoder Representations from Transformers (BERT) model. To this end, shotgather data generated from a synthetic model containing faults was used to perform noise reduction, velocity prediction, and fault detection tasks. In the task of random noise reduction, both the receiver and time arrays showed good performance. However, for tasks requiring the identification of spatial distributions, such as velocity estimation and fault detection, the results from the time array were superior.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.11 no.6
• /
• pp.93-100
• /
• 2003

This paper describes the thermoelastic instability arising from friction heat generation in braking and proposes the finite element methods to predict the variation of temperature and thermal deformation. In a conventional disc brake analysis, heat generation is only related with wheel speed and friction material and the interface pressure between disc and pad is assumed constant. But under dynamic braking conditions, the frictional heat causes the thermoelastic distortion that leads to more concentrated contact pressure distribution and hence more and more non-uniform temperature. In this paper, to complete the solution of the thermomechanically coupled problem, the linear relation model between pressure and temperature is proposed and demonstrated in examples of a simple two dimensional contact problem. And the two dimensional model has been extended to an annular three dimensional disc model in order to consider more realistic geometry and to provide a more accurate critical speed for automotive brake systems.

• Computational Structural Engineering
• /
• v.9 no.4
• /
• pp.181-187
• /
• 1996

This paper concerns the singular thermal stresses at the interface corner between the elastic fiber and the viscoelastic matrix of a two-dimensional unidirectional laminate model induced during cooling from cure temperature down to room temperature. Time-domain boundary element method is employed to investigate the nature of residual thermal stresses at the interface. Numerical results show that very large stress gradients are present at the interface corner and such stress singularity might lead to local yielding or fiber-matrix debonding.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.25 no.8
• /
• pp.1253-1260
• /
• 2001

Transient thermal analysis of a three-dimensional axisymmetric automotive disk brake is presented in this paper. Temperature fields are obtained using a hybrid FFT-FEM scheme that combines Fourier transform techniques and finite element method. The use of a fast Fourier transform algorithm can avoid singularity problems and lead to inexpensive computing time. The transformed problem is solved with finite element scheme for each frequency domain. Inverse transforms are then performed for time domain solution. Numerical examples are presented for validation tests. Comparisons with analytical results show very good agreement. Also, a 3-D simulation, based upon an automotive brake disk model is performed.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.8
• /
• pp.1451-1457
• /
• 1992

In hot strip rolling, the thickness of strip cannot be retained uniform by several irregular parameters. It has been shown that the load distribution can affect only a small fraction of the excess strip crown, whereas the thermal effects of working roll are the major reason on large changes in the strip center crown during hot rolling. In this study, the temperature distribution of working roll is represented by fourier series expansion. The analytical solution of the resulting thermo-elasticity problem is obtained by love's strain function. The results which are compared with those of the finite element method show good agreements.