• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.3
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• pp.273-279
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• 2011

The yield strength of particle-reinforced composites increases as the size of the particle decreases. This kind of length scale has been mainly attributed to the geometrically necessary dislocation punched around the particle as a result of the mismatch of the thermal expansion coefficients of the particle and the matrix when the composites are cooled down after consolidation. In this study, two dislocation-punching theories that can be used in continuum structural modeling are assessed numerically. The two theories, presented by Shibata et al. and Dunand and Mortensen, calculate the size of the dislocationpunched zone. The composite yield strengths predicted by finite element analysis were qualitatively compared with experimental results. When the size of the particle is less than $2{\mu}m$, the patterns of the composite strength are quite different. The results obtained by Shibata et al. are in qualitatively better agreement with the experimental results.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.4
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• pp.696-706
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• 1992

In sheet metal fabrication using NCT(numerically controlled turret), the automatic tool selection for the NCT operation is the major problem to be solved first to improve its production performance. However, the punching tool selection has been done by human experts either manually or semi-automatically. In this paper, we have introduced the shape-index-set to handle the shape of sheet metal parts and developed an algorithm through which one can find easily the successive matching curves between two curve lists, one from the punching tool and the other from the boundaries of the sheet metal part. Based on this algorithm, we have also devised the method that can select automatically the tools to punch out the boundaries of sheet metal parts. The result of several computational experiments shows the successful tool selection without any fail.

• Magazine of the Korea Concrete Institute
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• v.2 no.1
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• pp.101-108
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• 1990

An experimental and analytical invest.igation was conducted regarding the behavior of reinforced concrete skew bridge decb with Ontario-type reinforcement. A full-scale model repmsenting the essential behavior of a full skew bridge was built and tested. The test specimen had details similar to those required by the Ontario Highway Bridge Design Code, modified as recommended by the Texas State Highway Dopartment. The skuw bridge deck performed sati:,factorily under the current AASHTO design load le"els as well as the overload conditions(about :3 times the current AASHTO design wheel load). The skew edges failed by shear ; the center by punching shear. The calculated flexural capacity considering arching action always far exceeded the actual failure load (shear or punching shear) at each test location. To check the experimental results a detailed finite element model of the specimen was developed using a general-purpose structural analysis pmgram. Analytical predictions and exper'imental results agreed c1osuly.