• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.952-956
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• 1997

This paper describes the method that can expand the forming limit of T type forging products used in aircraft and automotive forged products. The forming limitis determined by the ratio of web thickness to rib width in T type and the reduction in height of workpiece and especially depends on the ratio of web thickness to rib width. For this method, the geometric condition that consists of triangle type was introduced and FEM simulations and model exoeriments were carried out and compared with each other. The objective of this paper is to give the method not only that sink mark and folding phenomenon are eliminated but also that the forming limit and the structural strength of rib and web is increased.

• Proceedings of the Korean Magnestics Society Conference
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• 2013.12a
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• pp.115-115
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• 2013

In order to pinpoint the different factors responsible for magnetization reversal, we performed simulation using OOMMF micromagnetic package for rectangular shaped permalloy element having length of $1{\mu}m$, width 50-100 nm and thickness 15-80 nm with length to width ratio L/W>4. Interestingly an increase in coercivity with thickness is found for every width below a critical thickness. With increasing width and thickness, the distinct behavior of coercivity, hysteresis loops and reversal mechanism are presented. Vortex end domains are observed during the magnetization reversal beyond particular thickness, where the three dimension reversal mechanism is expected to begin, causing a sudden increase in coercivity.

• Journal of Crop Science and Biotechnology
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• v.11 no.2
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• pp.151-156
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• 2008

The objective of this study is to identify main-effect QTLs, epistatic QTLs, and the interactions between QTL and the environment associated with grain appearances of brown rice. A genetic linkage map was created with 172 DNA markers spanning 12 rice chromosomes based on 120 DH lines, which derived from a cross between 'Samgang'(Tongil) and 'Nagdong'(Japonica). One thousandgrain weight, length, width, length-to-width ratio, and thickness were evaluated regarding the DH population. Twenty independent QTLs and fourteen epistatic QTLs were identified in using CIM by two programs, known as WinQTLcart2.5 and QTLMAPPER. The QTLs of qgw9.1 in an interval of RM434-RM242 on chromosome 9 and qgw11.1 at a peak marker of RM287 on chromosome 11 for one thousand-grain weight, qgwi2.2 for grain width at a peak marker of RM450, qlw2.1 for length-to-width ratio flanked by RM492 and RM324, and qgt2.1 for thickness flanked by 2009 and RM492 on chromosome 2 were detected over two years, which can be considered as stable QTLs. The epistatic effect might be an important component for genetic basis of one thousand-grain weight and width. The main-effect QTLs of grain width and length to width ratio were easily influenced by environments.

• Steel and Composite Structures
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• v.30 no.2
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• pp.123-140
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• 2019

This paper presents experimental study on effects of width-to-thickness ratio and loading history on cyclic rotational capacity of H-shaped steel beams subjected to pure bending. Eight Class 3 and 4 H-shaped beams with large width-to-thickness ratios were tested under four different loading histories. The coupling effect of local buckling and cracking on cyclic rotational capacity of the specimens was investigated. It was found that loss of the load-carrying capacity was mainly induced by local buckling, and ductile cracking was a secondary factor. The width-to-thickness ratio plays a dominant effect on the cyclic rotational capacity, and the loading history also plays an important role. The cyclic rotational capacity can decrease significantly due to premature elasto-plastic local buckling induced by a number of preceding plastic reversals with relative small strain amplitudes. This result is mainly correlated with the decreasing tangent modulus of the structural steel under cyclic plastic loading. In addition, a theoretical approach to evaluate the cyclic rotational capacity of H-shaped beams with different width-to-thickness ratios was also proposed, which compares well with the experimental results.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.429-437
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• 1999

Width variation of the top and bottom ends of steel at finishing rolling in a plate, has been investigated. It was found that width variation after finishing rolling is affected by edging, broadside rolling ratio, longitudinal rolling ratio, width shape after broadside rolling, temperature, width-to-thickness ratio, and so on. A neural network modelling of back propagation has been conducted on the width variation during rolling. Based on these prediction models, a width control system, by which the roll opening and closing of the hydraulic AWC edger can be adjusted during edge rolling in finishing rolling passes, has been developed. Compared to conventional width model, the neural network model is much accurate in a model. The width control system is applied to a newly built production mill.

• Journal of Korean Society of Steel Construction
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• v.26 no.4
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• pp.277-288
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• 2014

In this study, the local displacement and moment characteristics of a plate stiffened with closed ribs are analyzed according to the dimensions of stiffened plates. The analyzed results of various stiffened plates under square distributed load show that the effect of the loading panel width to the local behavior is dominant but that of the next panel width is very small. And the local behavior of reference stiffened plates can be expressed by the angle between the plate and the rib, and that of other stiffened plates can be obtained by multiplying ratio functions of the loading panel width, plate thickness, rib thickness, rib height and next panel width and they give good results. Applying ratio functions to other loading sizes shows that the applicability of ratio functions except for the loading panel width is proved and the modified ratio functions of the loading panel width improve error ratios. Therefore, the local displacement and moments of a plate stiffened with closed ribs can easily achieve proper results regardless of the dimensions using ratio functions proposed in this study.

• Steel and Composite Structures
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• v.8 no.5
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• pp.389-402
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• 2008

In December 2005, one(A) of the two pre-engineered warehouse buildings in the port of K City of Korea was completely destroyed and the other(B) was seriously damaged to be demolished. Over-loaded snow and unexpected blast of wind were the causes of the accident and destructive behavior was brittle fracture caused by web local buckling and lateral torsional buckling at the flange below rafter. However, the architectural design technology of today based on material non-linear method does not consider the tolerances to solve the problem of such brittle fracture. So, geometric non-linear evaluation which includes initial deformation, width-thickness ratio, web stiffener and unbraced length is required. This study evaluates the structural safety of 4 models in terms of width-thickness ratio and unbraced length using ANSYS 9.0 with parameters such as width-thickness ratio of web, existence/non-existence of stiffener and unbraced length. The purpose of this study is to analyze destructive mechanism of the above-mentioned two warehouse buildings and to provide ways to promote the safety of pre-engineered buildings.

• Steel and Composite Structures
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• v.14 no.5
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• pp.473-491
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• 2013

The primary objectives of this paper are to describe the buckling patterns and to determine the squash load of steel plate-concrete (SC) walls. The major variables in this study were the width-thickness (B/t) ratio and yield strength of surface steel plates. Six SC walls were tested, and the results include the maximum strength, buckling pattern of steel plates, strength of headed studs, and behavior of headed studs. Based on the test results, the effects of the B/t ratio on the compressive strength are also discussed. The paper also presents recommended effective length coefficients and discusses the effects of varying the yield strength of the steel plate, and the effects of headed studs on the performance of SC structures based on the test results and analysis.

• Journal of Korean Society of Steel Construction
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• v.17 no.4 s.77
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• pp.491-498
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• 2005

This study involves the development of a computer program to analyze the local buckling stresses for the flange and the web of I-beams under compression at elevated temperatures, and the optimization algorithm to analyze the optimum width-thickness ratios which does not occur their local buckling prior to yield failure. The high-temperature stress-strain relationships of steel used in this study were based on EC3 (Eurocode3) Part1.2 (2000b). In this study, the local buckling stresses and the optimum width-thichness ratios were analyzed considering the influences of the yield stress, local buckling coefficients and width-thickness ratios of the flange and the web. Design examples show the applicability of the computer program developed in this study.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.123-128
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• 2007

Demand for high quality rice has always been a major factor in the international rice marketing. In the present study, doubled haploid (DH) population derived from anther culture of a Tongil/japonica hybrid was used for genetic analysis of rice grain quality. The average values of DH lines for grain weight, grain length and the ratio of grain length to width were near the mid-parent value. More than 40% DH lines showed transgressive segregation for grain weight, length, amylose and lipid content, but less than 10% DH lines observed on ratio of length to width and grain thickness were transgressive segregation. Correlation analysis between appearance qualities and physicochemical characters indicated that grain width and grain thickness both significantly and negatively correlated to protein and lipid content. A highly significant negative correlation between protein content and amylose content was observed.