• Journal of the Korean Society for Precision Engineering
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• v.17 no.6
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• pp.143-152
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• 2000

The comer filling in shaped drawing process is an important characteristic, unlike the round drawing. It has also influence on the dimensional accuracy of the product. In this study, therefore, the shaped drawing process has been simulated by the three dimensional rigid-plastic finite element method in order to investigate the effect of process variables such as reduction in area and semi-die angle to the corner filling. The artificial neural network has also been introduced to reduce the number of simulations. To verify the results of simulations, experiments have been performed on the real industrial products. According to the results, the main process variable on the corner filling is the combination of semi-die angle in the irregular shaped drawing processes, but in the case of regular shaped drawing processes, reduction in area has great influence on the corner filling.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.05a
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• pp.56-59
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• 1999

In the present study, in order to investigate the effect of the corner filling in the drawing of the rectangular rod from a round bar, the drawing of the square rod from a round bar has been simulated by using rigid-plastic finite element method and artificial neural network has been introduced to reduce the number of simulation. The experimental investigation has been also implemented to verify the efficiency of the application of results of present and previous study. According to the results of present and pervious study, the combination of semi-die angle gives a great effect on the corner filling in case of the irregular shaped drawing process, but, in case of the regular shaped drawing process, the main process variable on the corner filling is reduction in area.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.99-102
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• 1999

In this study, to investigate the effect of process variables such as reduction in area, semi-die angle and the rectangular ratio to the corner filling which influences the dimensional accuracy of the final product in the drawing of the cluadrangle rod from a round bar, it has been simulated by three dimensional rigid-plastic finite element method. In order to reduce the number of simulation artificial neural network has been introduced. Also, through the experimental investigation, the present results have been implemented on the industrial product. In results, the main process variable is the combination of the semi-die angle in case of the irregular shaped drawing process and reduction in area in the event of regular shaped drawing process, respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1410-1413
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• 2003

Drawing is a basic plastic deformation method and productive manufacturing process make wire. rod and variety section geometry bar. Study for the rod drawing process of rod was researched long littles. but non-axisymmetric drawing process is weak. So metal flow is very irregular in non-axisymmetric drawing process and difficult to define about material deformation generally. In this paper, to solve material deformation, use finite element method and then define suitable shape for rod to hexagonal drawing dies. And research corner filling rate and surface roughness for the high strength steel hexagonal bar produced defined dies.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.03a
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• pp.205-209
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• 1998

Unlike the drawing of round section from round bar, the shaped drawing like polygonal section is known to have influence not only drawing stress but also comer filling. Therefore, this study analyze the drawing process of suqare rod from round bar using nonsteady state rigid-plastic FEM. To investigate effects of process variables of the drawing process of square rod from round bar, FE-simulations with variety of reduction in area and semi-die angle for a given frictional condition have been conduction. By this results, it has to suggest optimal process condition on the drawing stress and the comer filling. In addition, it has determined forming limit considering necking and bulging.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.11
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• pp.145-151
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• 1998

Unlike the drawing of round section from round bar, the shaped drawing like polygonal section is known to have influence not only drawing stress but also corner filling. Therefore. this study analyze the drawing process of suqare rod from round bar using nonsteady state rigid-plastic FEM. To investigate effects of process variables of the drawing process of square rod from round bar, FE-simulations with variety of reduction in area and semi-die angle for a given frictional condition have been conducted. By this results, it has to suggest optimal process condition on the drawing stress and the corner filling. In addition, it has determined forming limit considering necking and bulging.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.537-544
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• 2021

In order to describe the fill-up stages of a near-surface disposal facility vault, a mock-up test is performed, and its behavior during the fil l -up stages is investigated. On an in-site concrete foundation with a l ength of 6600mm, a width of 6600mm and a thickness of 400mm, a reinforced concrete disposal vaul t is manufactured with 4 precast (PC) corner wal l s and 8 PC side wal l s. 36 wasted drums are pl aced on the 1st fl oor in 6 by 6, and then the empty space is fil l ed with grout fil l er. These processes are repeated up to the 5th floor, and the verticality and the joint gaps are measured for each fill-up stage. The verticality is measured using a level at 6 positions on each side wall (3 positions on the left and right sides, respectivel y), i.e. a total of 24 positions on the 4 side wal l s. The joint gaps are measured at 9 positions on each side wal l (3 positions on the left, center and right sides, respectively), I.e. a total 36 positions on the 4 side walls. To measure the joint gaps, crack tips are installed on the left and right sides of every joint gap, and vernier calipers are used. The measured verticality obtained through the mock-up test was found to be ±0.1° based on the initial stage (ST0), and the result of the joint gap was up to 0.38mm. This appears to have a negligible effect on the structure.

• Journal of Korean Society of Steel Construction
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• v.23 no.4
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• pp.503-514
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• 2011

In this research, the seismic connection details for two concrete-filled U-shape steel beam-to-H columns were proposed and cyclically tested under a full-scale cruciform configuration. The key connecting components included the U-shape steel section (450 and 550 mm deep for specimens A and B, respectively), a concrete floor slab with a ribbed deck (165 mm deep for both specimens), welded couplers and rebars for negative moment transfer, and shear studs for full composite action and strengthening plates. Considering the unique constructional nature of the proposed connection, the critical limit states, such as the weld fracture, anchorage failure of the welded coupler, local buckling, concrete crushing, and rebar buckling, were carefully addressed in the specimen design. The test results showed that the connection details and design methods proposed in this study can well control the critical limit states mentioned above. Especially, the proposed connection according to the strengthening strategy successfully pushed the plastic hinge to the tip of the strengthened zone, as intended in the design, and was very effective in protecting the more vulnerable beam-to-column welded joint. The maximum story drift capacities of 6.0 and 6.8% radians were achieved in specimens A and B, respectively, thus far exceeding the minimumlimit of 4% radians required of special moment frames. Low-cycle fatigue fracture across the beam bottom flange at a 6% drift level was the final failure mode of specimen A. Specimen B failed through the fracture of the top splice plate of the bolted splice at a very high drift ratio of 8.0% radian.