• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.319-322
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• 2009

Roll bending process has been used for manufacturing the pipes. However, it is not suitable process for the thick pipes. Knife press forming is acceptable process for the thick pipes. Recently, the knife press forming process using brake bending press have been performed. In this study, the estimation on formability of knife press forming process for the thick pipes is carried out. From the results, it is ensured that the thick pipes could be obtained by the knife press forming process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1329-1330
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• 2011

• Transactions of Materials Processing
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• v.25 no.2
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• pp.116-123
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• 2016

Press-brake bending is used to shape flat and thick plates into a targeted circular configuration without excessive localized thinning or thickening. A brake bending press called 'a knife press bending apparatus' has been widely adopted to manufacture thick, large and long pipe from initially thick plate. Submerged Arc Welded (SAW) pipes are also produced by employing press-brake bending. These pipes are mainly used for oil, natural gas and water pipelines. The principal process variables for press-brake bending can be summarized as stroke of the press-brake knife, the distance between both roll in the lower die, and the feeding length of the plate. Many combinations of these process variables are available, thus various pipe diameters can be realized. In the current study, a series of repetitive numerical simulations by feeding a thick plate with initial thickness of 25.4mm were conducted with the consideration of elastic recovery. Furthermore, an index for SAW pipe production is proposed which can be widely used in industry.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.811-812
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• 2010

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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• pp.146-150
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• 2015

Steel is produced through the steel-making process with a desired shape by a rolling press. Scrap is removed according to the sheet edge to improve the quality of the product. This machine is called a side trimmer. This study aimed to develop a side trimmer for automatically changing the width of the trimming knife without line stopping. This machine consists of a housing opening device and a turning device. The measuring technologies of sheet width, trimming knife rotation angle, and knife gap for increasing the control accuracy. This experiment was conducted to evaluate the performance of the developed technologies. It was reduced by 10% compared with the operation time of the conventional method.

• 한국금형공학회:학술대회논문집
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• 2008.06a
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• pp.197-202
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• 2008

With the growth of electrical power needs, demand of the knife-type switches in the distribution boards is increasing. We have developed a knife-type switch which is not currently produced in Korea. The switch was desinged and a comprehensive tooling for it was also accomplished. A total of two sets of injection molds and three sets of press dies were designed and manufactured. The parts for knife switches were produced using the tools. Finally, the parts were assembled together and the switch is now under the test phase.

• Computers and Concrete
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• v.21 no.3
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• pp.321-333
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• 2018

Flat-slabs, being a significant structural component, not only reduce the dead load of the structure but also reduce the amount of concrete required for construction. Moreover the use of recycled aggregates lowers the impact of large scale construction to nearby ecosystems. Recycled aggregate based concrete being a quasi-brittle material shows enormous cracking during failure. Crack growth in flat-slabs is mostly in sliding mode (Mode II). Therefore sufficient sections need to be provided for resistance against such failure modes. The main objective of the paper is to numerically determine the ultimate load carrying capacity of two self-similar flat-slab specimens and validate the results experimentally for the natural aggregate as well as recycled aggregate based concrete. Punching shear experiments are carried out on circular flat-slab specimen on a rigid circular knife-edge support built out of both normal (NAC) and recycled aggregate concrete (RAC, with full replacement). Uniaxial compression and bending tests have been conducted on cubes, cylinders and prisms using both types of concrete (NAC and RAC) for its material characterization and use in the numerical scheme. The numerical simulations have been conducted in ABAQUS (a known finite element software package). Eight noded solid elements have been used to model the flat slab and material properties have been considered from experimental tests. The inbuilt Concrete Damaged Plasticity model of ABAQUS has been used to monitor crack propagation in the specimen during numerical simulations.