• Structural Engineering and Mechanics
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• v.53 no.2
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• pp.337-354
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• 2015

In this article, free vibration of functionally graded (FG) elliptic plates subjected to various classical boundary conditions has been investigated. Literature review reveals no study has been performed based on functionally graded elliptic plates till date. The mechanical kinematic relations are considered based on classical plate theory. Rayleigh-Ritz technique is used to obtain the generalized eigenvalue problem. The material properties of the FG plate are assumed to vary along thickness direction of the constituents according to power-law form. Trial functions denoting the displacement components are expressed in simple algebraic polynomial forms which can handle any edge support. The objective is to study the effect of geometric configurations and gradation of constituent volume fractions on the natural frequencies. New results for frequency parameters are incorporated after performing a test of convergence. A comparison study is carried out with existing literature for validation in special cases. Three-dimensional mode shapes for circular and elliptic FG plates are also presented with various boundary conditions at the edges.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2005.10a
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• pp.171-175
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• 2005

The Principle of space composition in modern architecture is thought about functionalism that based on function and program but the present age attempt that escapes form of former space composition. The present age brings fast development than former ages, so we need the space which has correct flexibility on New Age for escaping in existing structural formality. Specially, the space that boundary of existing plate, column and wall is crumbled as becoming possible technological support with social backgrounds. What this study saying is the analysis about the relation between the concept of topology and the consecutive space composition. Therefore, there is the purpose understanding a characteristic of continuity of the plate through the topological concept and understanding the roll in interior space.

• Journal of Korea Multimedia Society
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• v.11 no.12
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• pp.1649-1657
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• 2008

In this paper, to overcome the failure of binarization for the characters suffered from low contrast and non-uniform illumination in license plate character recognition system, we improved the binarization method by combining local thresholding with global thresholding and edge detection. Firstly, apply the local thresholding method to locate the characters in the license plate image and then get the threshold value for the character based on edge detector. This method solves the problem of local low contrast and non-uniform illumination. Finally, back-propagation Neural Network is selected as a powerful tool to perform the recognition process. The results of the experiments i1lustrate that the proposed binarization method works well and the selected classifier saves the processing time. Besides, the character recognition system performed better recognition accuracy 95.7%, and the recognition speed is controlled within 0.3 seconds.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.200-214
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• 1993

This paper presents the results of fluidelastic instability analysis performed for the U-tube bundle of a Westinghouse model 51 steam generator, one of the recirculating types designed at an early stage, in which the principal region of external cross-flow is associated with the U-bend portion of tube. The prerequisites for this analysis are detailed informations of the secondary side flow conditions in the steam generator and the free vibration behaviours of the U-tubes. In this study, the three-dimensional two-phase flow field in the steam generator has been calculated employing the ATHOS3 steam generator two-phase flow code and the ANSYS engineering analysis code has been used to calculate the free vibration responses of specific U tubes under consideration. The assessment of the potential instability for the suspect U-tubes, which is the final analysis process of the present work, has been accomplished by combining the secondary side velocity and density distributions obtained from the ATHOS3 prediction with the relative modal displacement and natural frequency data calculated using the ANSYS code. The damping of tubes in two-phase flow has been deduced from the existing experimental data by taking into account the secondary side void fraction effect. In operation of the steam generator, the tube support conditions at the tube-to-tube support plate intersections due to either tube denting degradation or deposition of tube support plate corrosion products or ingression of dregs. Thus, various hypothetical cases regarding the tube support conditions at the tube-to-tube support plate intersections have been considered to investigate the clamped support effects on the forced vibration response of the tube. Also, the effect of anti-vibration bars support in the curved portion of tube has been examined.

• Journal of the Korean Society for Nondestructive Testing
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• v.11 no.1
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• pp.7-12
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• 1991

The multi-frequency eddy current technique has been used for evaluation of various type of defects in tubings. However, this technique is not sufficient to detect and evaluate the defect in tubings if the defect is located in the geometrically complicated area(e. g. tube support plate, anti-vibration bar, tubesheet area) and mixing residue signal is significant to the defect signal. In order to improve the reliability of the multi-frequency eddy current technique, the effect of the interaction of mixing residue after frequency mixing with a function of distances between the defect and the tube support plate boundary has been analyzed theoretically. The experimental results have been discussed with the theoretical developments. The calculation shows the interaction between the two neighboring signal sources could be significant within the range of approximately 1.0mm with the experimental condition.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.409-414
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• 1998

In this paper, we present the results of finite element analyses pertaining to the mechanical behavior of simply supported skew concrete slab bridges. To investigate the bending behavior of skew concrete slab three skewed slabs are modelled with different plate aspect ratios. In each modelled skew plate, skew angles are varied from 0$^{\circ}$to 45$^{\circ}$ by 5$^{\circ}$interval. It is found that the support reactions at the obtuse corner are remarkably higher than the other support reactions. In the design of skew slab bridge bearings, the capacity of bearing installed at the obtuse corner should be very high or otherwise the spacing between the bearings at this corner must be adjusted appropriately to resist extra high reactions.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.302-307
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• 2004

The major flow-induced vibration mechanisms such as fluid-elastic and turbulence excitation can cause the various types of wear of the steam generator tubes in unclear power plant. It is generally accepted that the tube wear due to vibration is affected by the presence of gap clearance between tube and support plate. Connors showed that the tube wear depth could be estimated by using the relationship between wear volume and sliding distance for contact time. Au-Yang predicted the wear depth by using the nonlinear characteristics of normal work rate to contact time. In this study the effect of gap size on the steam generator tubes wear is analyzed by deriving the wear depth versus normal work rate relationship from these previous results.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.4
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• pp.554-559
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• 2010

Lifeboat davit is composed of main frame, main arm, upper arm and support bar. In this paper, design parameters that affect the bending stiffness were set as plate thickness, width and hight of upper arm. To analyze the influence of parameter factors, FEM and Taguchi Method were used. This paper will help substantially in many industries.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.331-342
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• 2005

This paper presents a non-destructive evaluation (NDE) technique for detecting damages on a jointed steel plate on the basis of the time of flight and wavelet coefficient, obtained from wavelet transforms of Lamb wave signals. Support vector machines (SVMs), which is a tool for pattern classification problems, was applied to the damage estimation. Two kinds of damages were artificially introduced by loosening bolts located in the path of the Lamb waves and those out of the path. The damage cases were used for the establishment of the optimal decision boundaries which divide each damage class's region from the intact class. In this study, the applicability of the SVMs was investigated for the damages in and out of the Lamb wave path. It has been found that the present methods are very efficient in detecting the damages simulated by loose bolts on the jointed steel plate.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.1
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• pp.251-258
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• 2003

This study is to understand the characteristics of axial force behavior that operates to the part of continuous welded rail and to investigate the basic data for secure the structure's stability and retrofit of the track. To develop the FEM model that type of plate girder which is used in the domestic national railway among servicing railway type. It is to analyze the characteristics of axial force behavior according to equip of the expansion joint and support placing by using the axial force simulation in making the continuous welded rail. As the result of research on the parametric valuables through the analysis, it is investigated that 'FMFM type' is more efficient than the other support type. Also, it conclude that structures are having the expansion joint is the most safe condition.