Transactions of Materials Processing (소성∙가공)

The Korean Society for Technology of Plasticity and materials processing (한국소성∙가공학회)
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Modeling the Behavior of Trapped Air in Die Cavity During Sheet Metal Forming

판재성형 해석시 금형내의 공기거동 모델링

  • 최광용 (강원대학교 기계의용공학과) ;
  • 김헌영 (강원대학교 기계의용공학과)
  • Received : 2011.07.06
  • Accepted : 2011.07.21
  • Published : 2011.08.01
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Abstract

During stamping processes, the air trapped between sheet metal and the die cavity can be highly compressed and ultimately reduce the shape accuracy of formed panels. To prevent this problem, vent holes and passages are sometimes drilled into the based on expert experience and know-how. CAE can be also used for analyzing the air behavior in die cavity during stamping process, incorporating both elasto-plastic behavior of sheet metal and the fluid dynamic behavior of air. This study presents sheet metal forming simulation combined simultaneously with simulation of air behavior in the die cavity. There are three approaches in modeling of air behavior. One is a simple assumption of the bulk modulus having a constant pressure depending on volume change. The next is the use of the ideal gas law having uniform pressure and temperature in air domain. The third is FPM (Finite point method) having non-uniform pressure in air domain. This approach enables direct coupling of mechanical behavior of solid sheet metal and the fluid behavior of air in sheet metal forming simulation, and its result provides the first-hand idea for the location, size and number of the vent holes. In this study, commercial software, PAM-$STAMP^{TM}$ and PAM-$SAFE^{TM}$, were used.

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References

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