• 소성∙가공
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• 제7권1호
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• pp.23-35
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• 1998

In order to analyze the tensile deformation characteristics of laser welded tailored blanks. laser welded blanks of different thikness and strength combinations were prepared and tensile tests were done. The tensile elongation along the direction perpendicular to weld line of laser welded blanks was reduced as increasing the deformation restraining force (strength X thicknes) ratio between two welded sheets and fracture occurred at weaker side of base sheets if void ration of welded sheets and fracture occurred at weaker side of base sheets if void ratio of weld section was less than 45% The tensile elongation along weld line reached above 90% of the elongation of base material if welding was done perfectly. Total elongation along the direction perpendicular to weld line was able to be predicted by force equilibrium and power law behavior of base sheets and it was related with the deformation of stronger sheet and formability of weaker side.

• 소성∙가공
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• 제7권1호
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• pp.36-48
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• 1998

In order to analyze the stretch flange forming characteristics of tailored blanks. laser welded blanks of different thickness and strength combinations were prepared and hole expansion tests were done. The stretch flange formability of laser welded blanks was reduced as increasing the deformation restraining force($strength{\times}thickness$) ratio between two welded sheets. Simulation of stretch forming mode deformation and comparson with experimental results showed that the stretch flange formabili-ty was influenced not only by the difference of the deformation restraining forces between two base sheets but also by the difference of the deformation restraining forces between base sheet and weld. Therefore the stretch flange formability was reduced more rapidly than tensile elongation as increas-ing the deformation restraining force ration. It was also found that simulation of stretch flange forming was more accurate when material properties of weld was given.

• 한국산업정보학회논문지
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• 제12권3호
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• pp.1-9
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• 2007

본 논문에서는 주화나 메달의 제조 공정에서 극인의 수명을 향상시키는 제조 조건에 대하여 연구하였다. 먼저, 경계요소법을 이용하여 응력의 주요 집중부를 찾아내어 실제 압인 실험에서 극인의 최초 균열 위치가 일치하는지를 검증하여 이를 금형의 수명을 측정하는 기준으로 사용하였다. 주화생산 조건의 요소 중, 완제품인 주화의 정해진 규격과 문양의 심도를 만족하는 범위 내에서 압인 공정의 주요 변수인 압인력과 칼라 및 소전의 크기 변화에 따른 금형의 수명을 비교하였다. 그 결과, 칼라와 소전의 직경을 조절하고 이 조건에 적합한 압인력을 사용하면 실험 대상 주화에서 극인의 수명이 최대 60% 증가하는 효과를 볼 수 있음을 보였다.