• Steel and Composite Structures
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• v.25 no.5
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• pp.625-638
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• 2017

This paper presents a novel approach that describes the first-order (linear elastic) partial interaction analysis of members formed by multi-components based on the Generalised Beam Theory (GBT). The novelty relies on its ability to accurately model the partial interaction between the different components forming the cross-section in both longitudinal and transverse directions as well as to consider the cross-sectional deformability. The GBT deformations modes, that consist of the conventional, extensional and shear modes, are determined from the dynamic analyses of the cross-section represented by a planar frame. The partial interaction is specified at each connection interface between two adjacent elements by means of a shear deformable spring distributed along the length of the member. The ease of use of the model is outlined by an application performed on a multi-component member subjected to an eccentric load. The values calculated with an ABAQUS finite element model are used to validate the proposed method. The results of the numerical applications outline the influence of specifying different rigidities for the interface shear connection and in using different order of polynomials for the shape functions specified in the finite element cross-section analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.2
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• pp.11-20
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• 1992

In general, the cross-section of a girder of a bridge has only one axis of symmetry. Therefore, lateral forces such as earthquake and wind may cause torsion coupled with lateral bending in the gider. This induces additional stresses especially in cables arranged in double-planes. Since this effect cannot be considered by using the conventional frame elements, the stiffness and the mass matrices of the geometrically nonlinear thin-walled frame element have to be used in order to model the girder. Theoretical development and verification of the frame element used in this study were made through a-previously presented paper. In this paper, seismic analysis of a three dimensional cable-stayed bridge considering the unsymmetry of the girder cross-section is performed to investigate the coupled flexural-torsional behaviors.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.4
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• pp.300-306
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• 2019

Transmission cross section(TCS) is described analytically as $2G{\lambda}^2/4{\pi}$ irrespective of the aperture shapes for various transmission resonant apertures, such as small ridged circular or H-shaped, U-shaped, or Jerusalem cross-shaped apertures in an infinite thin conducting plane. The proposed expression is validated by comparison with the numerical results obtained from the method of moments(MOM). The TCS characteristics of the transmission resonant cavity structure in a thick conducting plane are also studied and the equivalence between the two small aperture structures is reported from the viewpoint of transmission efficiency.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.5
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• pp.442-449
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• 2009

A two-dimensional cross-section analysis program based on the finite element method has been developed for composite blades with solid, thin-walled and compound cross-sections. The weighted-modulus method is introduced to determine the laminated composite material properties. The shear center and the torsion constant for any given section are calculated according to the Trefftz' definition and the St. Venant torsion theory, respectively. The singular value problem of cross-section stiffness properties faced during the section analysis has been solved by performing an eigenvalue analysis to remove the rigid body mode. Numerical results showing the accuracy of the program obtained for stiffness, offset and inertia properties are compared in this analysis. The current analysis results are validated with those obtained by commercial software and published data available in the literature and a good correlation has generally been achieved through a series of validation study.

• The Korean Journal of Cytopathology
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• v.17 no.2
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• pp.143-147
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• 2006

Merkel cell carcinoma (MCC), a rare primary cutaneous small cell neuroendocrine carcinoma, is a tumor with distinct cytological features. In many cases, immunohistochemical staining (IHC) is required for the differentiation from other small round cell malignancies. Here we describe the cytological findings of Merkel cell carcinoma; these findings contributed to the diagnosis prior to performing IHC. A lower eyelid mass was excised and submitted for frozen section diagnosis. The frozen section diagnosis was consistent with a malignancy, but the more specific diagnosis was limited by the lack of specific histological features. Touch imprint cytology revealed a high cellularity with loosely cohesive small to large sized cells. The tumor cells showed hyperchromatic nuclei with fine chromatin and inconspicuous nucleoli, and thin-rimmed-cytoplasm including the characteristic eosinophilic button-like paranuclear inclusion, previously described as a pathognomonic cytological finding of MCC; this was not found in the H&E frozen section. In conclusion, we suggest that the touch imprint cytology may help in the differential diagnosis of small round cell neoplasms prior to performing IHC especially in frozen section diagnosis.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.4
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• pp.73-82
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• 2016

Recently, automobile industries have been developing many structural automotive parts made of thin, high-strength steel strips to produce safer and more environmentally friendly cars. The roll forming process has been considered one of the most efficient processes in manufacturing high-strength steel parts because it is a high-speed process that forms sheets in increments. However, most automotive parts vary longitudinally in their cross-sections. Therefore, it is difficult to apply the roll forming process to automotive parts made of high-strength steel. A variable section roll forming process has been proposed in recent studies. The rotational axes of the forming rolls are fixed, and the forming rolls have three-dimensional shape. As such, the cross-section of the part varies linearly along its length, and the angle between the bend line and longitudinal axis is less than 1 degree. Thus, the rate of cross-sectional variation along the length is relatively small. In this study, the rate of cross-sectional change along the length of a forming roll has been increased. Moreover, the angle between the bend line and longitudinal axis has been increased up to 15 degrees. The variable sections of the forming rolls have been designed for high strength steel parts with a symmetric u-type cross-section that varies linearly and symmetrically along the longitudinal axis.

• Elastomers and Composites
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• v.1 no.1
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• pp.49-55
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• 1966

Based upon the results of the previous work, the experiments are concentrated on the improvement of the durability of rubber coated fabrics as a rain garment material. To obtain a much lighter and durable coated fabric, several kinds of light weight cotton prints having almost equal density in warp and fillingwise were chosen. Rubber coating on these prints was made by topping and spreading process using rubber compound of various viscosity, and the physical properties of final product were analysed and interpreted in terms of adhesion and durability. The results are as follows. 1. Any noticeable difference between two coating processes was not found in terms of physical properties. 2. Base fabrics should be dipped once into a dilute rubber compound before coating operation in order to obtain a uniform adhesion and physical properties, and the optimum range of the viscosity of dipping paste are from 100 poise to 200 poise. 3. Generally, the tearing strength of the coated fabrics is inversely proportional to the adhesion. 4. It was assumed that the increase of the water proofness after water immersion on the finished material which have dense base fabric is chiefly due to the swelling of the cellulosic fiber.

• Journal of Korean Vacuum Science & Technology
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• v.6 no.2
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• pp.71-75
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• 2002

GaAs polycrystalline thin films with good performance were prepared on conducting glass by hot wall epitaxy (HWE), which were used for solar cell. Electron probe micro-analyzer (EPMA) was applied for the composition, morphology of surface and cross-section of grown films, and X-ray diffraction (XRD) for their phase structure; Raman scattering spectum (RSS) and photoluminescence (PL) were used for evaluating their optical characteristics. The results show that, there is textured structure on the surface of grown GaAs polycrystalline films, which is greatly promised to be suitable for the candidate of solar cell with low cost and high efficiency. It is concluded that the source and substrate at temperature of 900 ~ 930 $\^{C}$ and 500 $\^{C}$ respectively would be beneficial for such films.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.1
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• pp.71-81
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• 1994

A method is presented for the analysis of curved segmentally erected prestressed concrete box girder bridges including time-dependent effects due to load history, temperature history, creep, shrinkage, aging of concrete and relaxation of prestressing steel. The segments can be either precast or cast-in-place. Thin-walled beam theory and finite element method are combined to develop a curved nonprismatic thin-walled box beam element. The element consists of three nodes and each node has eight displacement degrees of freedom, including transverse distortion and longitudinal warping of the cross section.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.1
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• pp.1-12
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• 1993

Tangent stiffness matrices are derived for the torsional and lateral stability analysis of the space beams and framed structures with the symmetric thin-walled section by using the principle of virtual displacement. In the cases of restrained torsion and unrestrained torsion, the elastic and geometric stiffness matrices are evaluated by using the Hermitian polynomials which represent the displacement field of the beam element in simple flexure. Numerical examples illustrate the accuracy and convergence characteristics of the derived formulations.