• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.3
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• pp.483-492
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• 1998

An inverse analysis been applied to obtain the flow stress of the material. In this method, a ring-shaped specimen is compressed between two flat tools. This procedure employs, as the object function of inverse analysis, the balance of measured loads and reaction forces calculated by using rigid-plastic finite element method. The balance is explicit scalar function of flow stress which is a function of some unknown constants. For minimizing the balance, Newton-Raphon scheme is used. The friction factor, m, between flat tools and the specimen is determined by using friction area-divided method. The proposed method allows an accurate identification by avoiding the usual assumptions made in order to convert experimental measures into stress-strain relation. In this paper, the proposed method is numerically tested. A commercial pure aluminum was selected, as an example, to apply the method and the results are compared with stress-strain relation obtained by experiments.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.6
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• pp.907-914
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• 2012

Flexible pipes take advantage of their ability to move, or deflect, under loads without structural damage. Common types of flexible pipes are manufactured from polyethylene (PE), polyvinyl chloride (PVC), steel, glass fiber reinforced thermosetting polymer plastic (GFRP), and aluminum. In this paper, we present the result of an investigation pertaining to the short-term behavior of buried polyethylene pipe. The mechanical properties of the polyethylene pipe produced in the domestic manufacturer are determined and the results are reported in this paper. In addition, vertical ring deflection is measured by the laboratory model test and the finite element analysis (FEA) is also conducted to simulate the short-term behavior of polyethylene pipe buried underground. Based on results from soil-pipe interaction finite element analyses of polyethylene pipe is used to predict the vertical ring deflection and maximum bending strain of polyethylene pipe.

• Journal of the Korean Geotechnical Society
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• v.20 no.6
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• pp.5-10
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• 2004

The earth pressure coefficient at rest for clayey soils in the one-dimensional state, $K_0$ obtained from the triaxial test is not correct in principle because the seepage flow is radial and the displacement of soil elements is three-dimensional. Measurements of the earth pressure and the pore water pressure during one-dimension consolidation in the consolidometer ring are presented. The earth pressure and pore water pressure are measured directly by a circular part of the consolidometer ring of a floating type at its mid height. A plastic clay showed $K_0$=0.5 irrespective of pressure in the consolidometer ring.

• Journal of environmental and Sanitary engineering
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• v.15 no.3
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• pp.94-100
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• 2000

This study was carried out to interpret hydraulic behavior and CO2 gas desorption in counter-current packing tower which packed 50mm plastic Hiflow-ring. The results are as follow : To compare with conventional packing, 50mm Hiflow-ring could save energy because of low pressure drop under high load. As relative error between calculated value and investigated value was less than 6% in the loading point and flooding point we found that we are predict results mathematically which occur in packing tower. The unique magnitude of packing which was used are as follows. $C_L=2.1{\times}10^{-4}$, n=0.787 so we can predict efficiency which occur

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.03a
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• pp.80-91
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• 1994

This study aims detecting forming defects for the forming process of bearing rings, which is designed by an industry expert. The designed process consists of one forming operation for the outer ring and four operations for the inner ring. The thickness of the sheet used is 1.6mm, and is in between of thin sheet and bulk material. Here the rigid-plastic finite element method is applied to the analysis and design of the process without considering anisotropy of thin sheet. Thinning and folding defects are detected if the initially designed process is applied for manufacturing. so a new process is designed by referring the results of the FEM. It is confirmed that the industry expert agree the possibility of defects derived from FEM results.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1680-1682
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• 2007

The integrated circuits such as inverters, ring oscillators, NAND and NOR gates, and rectifiers were fabricated on PEN substrate by using pentacene TFTs. The OTFTs used bottom contact structure and produced the average mobility of $0.26\;cm^2/V.sec$ and on/off current ratio of $10^5$. All circuits worked successfully like the simulation results. Especially, the rectifier was able to operate up to 1 MHz input signals, and ring oscillator exhibited oscillation frequency of 1MHz at-40V.

• Transactions of Materials Processing
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• v.3 no.2
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• pp.189-201
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• 1994

This study aims detecting forming defects for the forming process of bearing rings, which is designed by and industry expert. The designed process consists of one forming operation for the outer ring and four operations for the inner ring. The thickness of the sheet used is 1.6mm, and is in between of thin sheet and bulk material. Here the rigid-plastic finite element method is applied to the analysis and design of the process without considering anisotropy of thin sheet. Thinning and folding defects are detected if the initially designed process is applied for manufacturing. So a new process is designed by referring the results of the FEM. It is confirmed that the industry expert agree the possibility of defects derived from FEM results.

• Steel and Composite Structures
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• v.22 no.1
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• pp.183-201
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• 2016

Perforated steel beams can be optimised by increased beam depth and the moment of inertia combined with a reduced web thickness, favouring the use of original I-section beams. The designers are often confronted with situations where optimisation cannot be carried out effectively, taking account of the buckling risk at web posts, moment-shear transfers and local plastic deformations on the transverse holes of the openings. The purpose of this study is to suggest solutions for reducing these failure risks of tested optimal designed beams under applying loads in a self-reacting frame. The design method for the beams is the hunting search optimisation technique, and the design constraints are implemented from BS 5950 provisions. Therefore, I have aimed to explore the strengthening effects of reinforced openings with ring stiffeners, welded vertical simple plates on the web posts and horizontal plates around the openings on the ultimate load carrying capacities of optimally designed perforated steel beams. Test results have shown that compared to lateral stiffeners, ring and vertical stiffeners significantly increase the loadcarrying capacity of perforated steel beams.

• Land and Housing Review
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• v.7 no.4
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• pp.323-328
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• 2016

There are small box opening for inserting of electric lamp box in the slab of apartment. Around this box opening, we normally use the detailing of WWF or plastic ring strengthening to protect cracks induced by shrinkage. The shrinkage amount of slab box around was measured and analysed in order to consider validity of these strengthening methods and to find out economical alternative. Alternative of strengthening methods are normally used strengthening methods in construction companies, which are WWF strengthening, plastic ring strengthening and no strengthening methods. The shrinkage amount was measured using contact guage at the spot of tip attached around the box on slab of small area unit apartment which have small exclusive area below $59m^2$. Measured data shows that there are no big differences between all the 3 strengthening methods and Measure data range is $-264{\mu}{\varepsilon}{\sim}+216{\mu}{\varepsilon}$. Measured shrinkage is on trend slightly increase till 3~5weeks after removal of forms and then decrease. But amount of shrinkage are very low for all the slabs and there are no probabilities of concrete crack by shrinkage.

• Archives of Plastic Surgery
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• v.34 no.6
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• pp.796-798
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• 2007

Purpose: Giant cell tumor is the second most common benign neoplasm in upper extremity. Unlike usual chief complaint of painless mass, an atypical case with giant cell tumor presented a distinguishing characteristics of which accompany pain and tenderness and is histologically giant-cell free. Methods: A 31-year-old male patient complained of a rapid growing painful mass on the proximal phalanx of the left ring finger. Under microscopic operation, a $1.6{\times}1.3cm$ sized mass was found to be surrounded by areolar tissue and attached to a tendon sheath, encircling the digital nerve and artery. Diagnostic confirmation was assisted by positive finding in histologic immunohistochemical stain-CD68. Characteristic pathologic finding is an atypical distribution of spindle cells & histiocytes without giant cells in fascicular pattern. Results: Giant cell tumor was carefully removed under microscopic approach, while preserving digital nerve & artery. In postoperative 13th month, the patient presented with a 6mm of static two-point discrimination test, similar to that of the adjacent fingers. Conclusion: We report an atypical case with painful mass on tendon sheath, surrounding the digital nerve and artery that was diagnosed of giant cell tumor, but without giant cells on pathology. This case provides broader understanding of the giant cell tumor that should not only rely its typical findings of the painless mass and positive sign on H&E stain.