• Journal of the Korea Concrete Institute
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• v.23 no.3
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• pp.365-376
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• 2011

The current Concrete Structural Design Code (2007) prescribe the equivalent rectangular stress block of the ACI 318 Building Code as concrete compressive stress distribution for design of concrete structures. The rectangular stress block may be enough for flexural strength calculation, but realistic stress-strain relationship is required for performance verification at selected limit state in performance-based design. Moreover, the ACI rectangular stress block provides non-conservative flexural strength for high strength concrete columns. Therefore a new stress distribution model is required for development of performance-based design code. This paper proposes a concrete compressive stress-strain distribution model for design and performance verification. The proposed model has a parabolic-rectangular shape, which is adopted by Eurocode 2 and Japanese Code (JSCE). It was developed by investigation of experimental test results conducted by the authors and other researchers. The test results cover high strength concrete as well as normal strength concrete. The stress distribution parameters of the proposed models are compared to those of the ACI 318 Building Code, Eurocode 2, Japanese Code (JSCE) and Canadian Code (CSA) as well as the test results.

• Structural Engineering and Mechanics
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• v.26 no.2
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• pp.151-162
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• 2007

Rigorous analytical solutions are obtained for the plane stress problem of a rectangular plate subjected to non-linearly distributed bending loads on two opposite edges. They are then used in a Galerkin type solution to obtain the corresponding convergent buckling loads. It is shown that the critical bending moment depends significantly on the actual edge load distribution and further the number of nodal lines of the buckled configuration can also be different from that corresponding to a linear antisymmetric distribution of the bending stresses. Results are tabulated for future use while judging approximate numerical solutions.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.10a
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• pp.111-118
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• 1995

A method of determining an optimum blank shape for the non circular deep drawing process is more investigated and applied to the balnk design for multi-stage deep drawn product. The forming procedure of two-stage deep drawing process is looked over and the method of determining a blank shape is proposed. In experimental research, a optimum blank and a optional rectangular blank were considered and we measured thickness strain distributions. We could predict a strain distribution and compare with a experimental strain distribution. Also, the strain distributions for the blank shapes, optimum and rectangular, were compared.

• Journal of Welding and Joining
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• v.25 no.3
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• pp.85-91
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• 2007

The conventional study on the laser surface transformation hardening has been carried out with a beam of the specified shape and uniform power-intensity distribution in order to ensure the uniformity of the hardening depth. Two types of beams - the circular gaussian beam and rectangular beam of the uniform power-intensity distribution were used in this study. we were supposed to optimize the process parameters and to compare the hardening results with two optics respectively. As a result, the hardness distribution of the hardened zone was similar in both cases and the hardened phase by the rectangular beam was denser than that by the circular gaussian beam.

• Design & Manufacturing
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• v.16 no.2
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• pp.60-65
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• 2022

In the pultrusion process for the CFRP (Carbon fiber reinforced plastic) rectangular pipe, the drawing device is eseential which can continuously produces products and draws the carbon fiber tow. In addition, since the degree of cure changes depending on the temperature and the temperature ditribution of the curing mold changes depending on the pultrusion speed, the temperature distribution of the curing mold under certain conditions must be studied before processing. In this study, in the pultrusion process using a closed impregnation method, which has several advantages compared to the general pultrusion process using a open bath impregnation method, the drawing force required to pull the carbon fiber tows and the temperature distribution of the curing mold was analyzed to design the drawing device and the curing mold efficiently.

• Wind and Structures
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• v.23 no.5
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• pp.465-483
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• 2016

This study aims to enhance the understanding of the surface pressure distribution around rectangular bodies, by considering aspects such as the suction pressure at the leading edge on the top and side faces when the body aspect ratio and wind direction are changed. We carried out wind tunnel measurements and numerical simulations of flow around a series of rectangular bodies (a cube and two rectangular bodies) that were placed in a deep turbulent boundary layer. Based on a modern numerical platform, the Navier-Stokes equations with the typical two-equation model (i.e., the standard $k-{\varepsilon}$ model) were solved, and the results were compared with the wind tunnel measurement data. Regarding the turbulence model, the results of the $k-{\varepsilon}$ model are in overall agreement with the experimental results, including the existing data. However, because of the blockage effects in the computational domain, the pressure recovery region is underpredicted compared to the experimental data. In addition, the $k-{\varepsilon}$ model sometimes will fail to capture the exact flow features. The primary emphasis in this study is on the flow characteristics around rectangular bodies with various aspect ratios and approaching wind directions. The aspect ratio and wind direction influence the type of wake that is generated and ultimately the structural loading and pressure, and in particular, the structural excitation. The results show that the surface pressure variation is highly dependent upon the approaching wind direction, especially on the top and side faces of the cube. In addition, the transverse width has a substantial effect on the variations in surface pressure around the bodies, while the longitudinal length has less influence compared to the transverse width.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.4
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• pp.57-62
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• 2011

In this study, a experimental work to investigate the influence of a turbulent wake flow on the velocity distribution of a diffuser with PIV method. The turbulent wake is generated by a rectangular prism, which is installed at the inlet of a diffuser. The results show that the velocity recovery of the subsonic diffuser is dependent on the height and location of rectangular prism. It is found that a certain height of the rectangular prism to generate the turbulent wake give a better velocity recovery, compared with no rectangular prism.

• The Journal of the Acoustical Society of Korea
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• v.23 no.1
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• pp.40-46
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• 2004

The equivalent source method (ESM) uses two groups of equivalent source positions. One group includes the first order images of the sound source inside the enclosure. The positions of the other group are usually on a spherical surface some distance outside the enclosure. A proper selection of the positions for the far field sources could greatly improve the performance of the modeling accuracy and reduce the number of the sources to achieve the required accuracy. This study uses optimally distributed far field source positions on the surface of enlarged version of the rectangular enclosure instead of using typical spherical distribution. Simulations using various sizes of the box shaped distribution are executed and optimal positions are searched using an optimization technique from the larger number of candidate positions. The results of using these far field source positions are compared and analyzed.

• Communications for Statistical Applications and Methods
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• v.8 no.1
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• pp.117-126
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• 2001

We provide a simple chi-squared test of multivariate normality based on rectangular cells on the spherical data. This test is simple since it is a direct extension of the univariate chi-squared test to multivariate case and the expected cell counts are easily computed. We derive the limiting distribution of the chi-squared statistic via the conditional limit theorems. We study the accuracy in finite samples of the limiting distribution and then compare the poser of our test with those of other popular tests in an application to a real data.

• Journal of architectural history
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• v.19 no.5
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• pp.7-23
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• 2010

The aim of this study is to analyze the planar composition of rectangular formation houses in 8 areas, both cities and counties, in the sphere of Andong and to reveal the characteristics of these houses in each region. This study of the rectangular formation of houses and their characteristics will facilitate an understanding of the general trends of housing in Andong cultural area.. In this study, the subject houses are composed of three parts: Bonchae, Anchae, and Sarangchae, and the author classified the planar types of the houses. The differences in the regional planar types were analyzed through visual and statistical methods. The analyzed results reveal the regional characteristics of the rectangular formation houses in terms of their planar aspects in the Andong region. The distribution showed the greatest preference toward one type out of two types of distribution of Bonchae, Anchae, and Sarangchae. The ratio for the higher distribution was approximately 70%, whereas the ratio for the lower distribution was around 20%. For convenience, the type with a higher distribution rate is referred to as the "major type," and the type with a lower distribution rate is termed the "minor type." The complete-type houses (73%) in Bonchae were a major type there, and the symmetric-type houses (73%) in Anchae were the major type in that location. In addition, the corner-type houses (72%) in Sarangchae were the major type. In the regional distribution of major types and minor types in the 8 regional cities and counties, regional differences were noted. The three regional groups can be divided into A, B, and C according to the distribution ratio. Andong, Bonghwa, and Yecheon belong to region A. that shows a variety of distribution types and a dispersive trend. Yeongyang and Yeongdeok belong to region C that shows a simplified trend.Yeongju and Cheongsong belong to region B.