• Composites Research
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• v.28 no.4
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• pp.204-211
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• 2015

This paper presents a theory related to a two-dimensional linear cross-sectional analysis, recovery relationship and a one-dimensional nonlinear beam analysis for composite wing structure with initial twist. Using VABS including a related theory, the design process of the composite rotor blade has been described. Cross-sectional analysis was performed at cutting point including all the details of geometry and material. Stiffness matrix and mass matrix were linked to each section to make 1D beam model. The 3D strain distributions within the structure were recovered based on the global behavior of the 1D beam analysis and visualize numerical results.

• Steel and Composite Structures
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• v.18 no.4
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• pp.985-1000
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• 2015

The method of cross-section analysis for different sections in a structural frame has been widely investigated since the 1960s for determination of sectional capacities of beam-columns. Many hand-calculated equations and design graphs were proposed for the specific shape and type of sections in pre-computer age decades ago. In design of many practical sections, these equations may be uneconomical and inapplicable for sections with irregular shapes, leading to the high construction cost or inadequate safety. This paper not only proposes a versatile numerical procedure for sectional analysis of beam-columns, but also suggests a method to account for residual stress and geometric imperfections separately and the approach is applied to design of high strength steels requiring axial force-moment interaction for advanced analysis or direct analysis. A cross-section analysis technique that provides interaction curves of arbitrary welded sections with consideration of the effects of residual stress by meshing the entire section into small triangular fibers is formulated. In this study, two doubly symmetric sections (box-section and H-section) fabricated by high-strength steel is utilized to validate the accuracy and efficiency of the proposed method against a hand-calculation procedure. The effects of residual stress are mostly not considered explicitly in previous works and they are considered in an explicit manner in this paper which further discusses the basis of the yield surface theory for design of structures made of high strength steels.

• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.155-162
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• 2004

An analytical method to predict the time dependent flexural behavior of composite girder is presented based on sectional analysis. The time dependent constitutive relation accounting for the early-age concrete properties including maturing of elastic modulus, creep and shrinkage is derived in an incremental format by the first order Taylor series expansion. The sectional analysis calculates the axial and curvature strains based on the force and moment equilibriums. The deflection curve of the girder approximated by the quadratic polynomial function is calculated by applying to the proper boundary conditions in the consecutive segments. Numerical applications are made for the 3-span double composite steel box girder which is a composite bridge girder filled with concrete at the bottom of the steel box in the negative moment region. The calculated results are compared with those by finite element analysis results. Close agreement is observed between the two approaches.

• Fire Science and Engineering
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• v.25 no.6
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• pp.83-88
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• 2011

This study presented the structure and characteristics of vinyl cords used for wiring electric equipment and appliances and analyzed the photographs of damaged flat-type vinyl cords (VFF, $1.25mm^2$) and the metallic cross-sectional structure of melted conductors. Normal VFFs were made by twisting several strands together and the surface of the conductor was red brown. In addition, from the analysis of the metallic structure of the conductor, it was found that its grains had been elongated. The surface of a VFF damaged by normal flame showed no sheen with carbonized insulation material fused on the conductor surface. In addition, from the analysis of the cross-sectional structure of the melted area, it was found that voids of a certain shape were formed on it but that the cord's own elongation structure could not be checked. The cross-sectional analysis of the melted conductor damaged by the external flame applied to a VFF to which electric current was being applied showed no elongation structure for each cord, and revealed that irregular voids and a columnar structure had grown. The surface of the VFF damaged by overcurrent was uniformly carbonized and the cross-sectional structure analysis of the melted conductor revealed that the dendritic structure had grown. The analysis of the characteristics of the VFF melted by short-circuit showed that even though some part of the surface was contaminated, it showed little sheen and that the area rebounded by melting was round in shape. In addition, the cross-sectional structure analysis using a metallurgical microscope showed the boundary surface and columnar structure and revealed an amorphous structure like normal copper at areas other than the melted conductor.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.197-201
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• 2007

Vibration characteristics of an annular cylindrical fuel rod, which was proposed as a candidate design of fuel's cross section for the ultra-high burnup nuclear fuel, according to the cross-sectional dimensions and the number of supports or the span length were analytically studied. Finite element(FE) modeling for the annular cross sectional fuel was based on the methodology, that have been proven by the test verification, for the conventional PWR nuclear fuel rod. A commercial FEA code, ABAQUS, was used for the FE modeling and analysis. A planar beam element (B21) that uses a linear interpolation was used for the fuel rod and a linear spring element for the spring and dimple of the SG. Natural frequencies and mode shape were calculated according to the preliminary design candidates for the fuel's cross sectional dimension and the number of span. From the analysis results, the design scheme of the annular fuel compatible to the present PWR nuclear reactor core was discussed in terms of the number of supports and fuel's cross section.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3A
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• pp.145-152
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• 2011

Current Bridge Specification for Highway Bridges adopts a simplified method to determine sectional forces of abutment wing by dividing its area into four sections. This simplified method was developed in Japan when numerical analysis was not mature and computer resources were expensive. This simplified method has been with us without modification. This study evaluates the problem of current design practice to improve the design guideline for abutment wing. In this study, a finite element model of abutment wing based on shell elements was developed to obtain accurate sectional force. In addition, foreign design specifications regarding abutment wing were thoroughly examined. It has been observed that sectional forces obtained from the simplified method produce inaccurate results under various geometric shapes. Thus, it is recommended that two dimensional plate analyses should be adopted for future design of abutment wing wall.

• Tribology and Lubricants
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• v.32 no.3
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• pp.101-105
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• 2016

Trap effect of groove is evaluated in a lubricating system using computational fluid dynamics (CFD) analysis. The simulation is based on the standard k-ε turbulence model and the discrete phase model (DPM) using a commercial CFD code FLUENT. The simulation results are also capable of showing the particle trajectories in flow field. Computational domain is meshed using the GAMBIT pre-processor. The various grooves are applied in order to improve lubrication characteristics such as reduction of friction loss, increase in load carrying capacity, and trapping of the wear particles. Trap effect of groove is investigated with variations in cross-sectional shape and Reynolds number in this research. Various cross-sectional shapes of groove (rectangular, triangle, U shaped, trapezoid, elliptical shapes) are considered to evaluate the trap effect in simplified two-dimensional sliding bearing. The particles are assumed to steel, and defined a single particle injection condition in various positions. The “reflect” boundary condition for discrete phase is applied to the wall boundary, and the “escape” boundary condition to “pressure inlet” and “pressure outlet” conditions. The streamlines are compared with particles trajectories in the groove. From the results of numerical analysis in the study, it is found that the cross-sectional shapes favorable to the creation of vortex and small eddy current are effective in terms of particle trapping effect. Moreover, it is found that the Reynolds number has a strong influence on the pattern of vortex or small eddy current in the groove, and that the pattern of the vortex or small eddy current affects the trap effect of the groove.

• Journal of Biomedical Engineering Research
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• v.41 no.6
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• pp.219-227
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• 2020

In this study, we tried to quantify the actual cross-sectional area inside the bore when scanning by the MRI system with various bore sizes. To this end, a comparative analysis was conducted by both of blueprint of each MRI equipment and actual measurement in the field. As a result of analysis, ACSA(Actual Cross-Sectional Area) in Ingenia CX, Elition X, uMR 780, Omega, Vida, Lumina, Architect, Premier is recorded as 171230, 232150, 242100, 309332, 230760, 230760, 229380 and 235990 ㎟, respectively ACSA% was 60.6, 60.3, 73.0, 70.0, 60.0, 60.0, 59.6, and 61,3%. In addition, DTB (Distance from Table top to Bore top) recorded 400, 407, 445, 495, 405, 405, 405, 403, and 412 mm. Through this study, it was confirmed that there is a difference between the bore size according to each MRI system and the actual cross-sectional area during MRI scanning. Accordingly, if we consider the internal actual area just not bore size at the clinical site, useful diagnostic images can be obtained in the end with better convenience.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.4
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• pp.396-408
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• 2023

The purpose of this study was to compare the proximal surface contour, size of contact area, and volume difference before and after restoration in artificial teeth of primary molars during proximal composite resin restoration using different matrix systems. Four types of artificial teeth were restored with composite resin using sectional matrix systems-Palodent V3 Sectional Matrix System and myJunior Kitand a circumferential matrix system-Tofflemire Matrix System-and modeled threedimensionally for analysis. When sectional matrix systems were used, there was a higher probability of concave proximal surface contour and simultaneously greater contact area and volume. This is attributed to the dead soft properties of the matrix band used in sectional matrix systems, which can lead to deformation of the band and hence an excessive amount of resin applied around the contact point. Additionally, the rubber wedge in the sectional matrix system may not help the matrix band fit into the cavity. Therefore, based on the findings of this study, morphological aspects need to be carefully considered for proximal composite resin restoration of primary molars using sectional matrix systems.

• Journal of the Semiconductor & Display Technology
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• v.11 no.4
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• pp.43-48
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• 2012

The screen printing method is much used in the flat panel display field including the LCD, PDP, FED, organic EL, and etc. for forming the high precision micro-pattern. Also A number of studies of screen printing method has been conducted as the method for the cost down through the improvement of productivity. Because of being the dot printing method of the cylindrical shape not being the line printing method like the existing PDP barrier rib and phosphor, the pillar arrays using the screen printing method is deposited in the hemispherical type not being cylindrical shape in the existing printing process conditions. In this paper, the parameters were set on the screen printing device in order to deposit the cross-sectional shape with the cone or trapezoid shape of the pillar in depositing the pillars used the screen printing device for vacuum glazing. The cross-sectional shape slope of the pillar according to the parameters was measured. And analysis the effect of the screen printing process conditions on the cross-sectional shape slope of pillars based upon the result of being measured. The processing conditions were drawn to minimize the cross-sectional shape slope of pillar.