薄壁锥形件拉深成形条件研究

在考虑了薄壁锥形件拉深过程中侧壁压缩失稳和小端拉裂两种破坏方式后，利用薄板在板平面内难以承受压应力，锥壁纬向收缩靠经向拉伸的变形特点，根据薄壁锥形件小端危险面所能提供的最大经向拉应力，求得了锥壁纬向无压缩失稳的最大相对拉深高度；根据薄壁锥形件的最大拉深载荷与毛坯外径的关系，求得了薄壁锥形件小端无破裂的最大相对拉深高度；从而建立了薄壁锥形件拉深的成形条件。针对板材性能的影响，提出了相对锥顶半径特征方程和特征值的概念。以Spcc深拉深钢板和S754铝合金板的试验表明，理论计算与实测结果相近。

STUDY ON THIN WALL TAPERED SHELL DRAWING FORMING CONDITION

Two kinds of failure during tapered shell drawing, the compression buckling of sidewall and the fractures in the smaller end, are investigated. During tapered shell drawing along the sheet it is hard for the sheet to sustain compression and the sheet contracts latitudinally and stretches longitudinally. Taken these into considerations, the maximum relative drawing depth is worked out to get a tapered shell drawpiecewithout latitudinal buckling in the sidewall according to the longitudinally maximum tensile stress the tapered shell draw-piece can endure and acquire the maximum relative drawing depth that can avoid fractures in the dangerous areas of the smaller end. Consequently, the forming condition of tapered shell drawing and the characteristc equation and eigenvalue of relative cone radius is established. Good agreement is found between the theoretical calculations and the results from the experiment that uses SPCC deep drawing sheet and S754 Aluminum alloy sheet as workpieces.