Consideration on Frictional Laws and their Effect on Finite Element Solutions in Bulk Metal Forming

체적소성가공에서 마찰법칙이 유한요소해석 결과에 미치는 영향에 관한 고찰

Effects of frictional laws on finite element solutions in metal forming were investigated in this paper. A rigid-viscoplastic finite element formulation was given with emphasis on the frictional laws. The Coulomb friction and the constant shear friction laws were compared through finite element analyses of compression of rings and cylinders with different aspect ratios, ring-gear forging, multi-stage cold extrusion and hot strip rolling under the isothermal condition. It has been shown that two laws may yield quite different results when the aspect ratio of a process and the fractional contact region are large.