板材冲挤复合成形模拟与裂纹预测

Simulation and fracture prediction of the combined blanking and extrusion process of sheet metal

板材冲挤复合成形是一种厚板近净形成形工艺,在汽车零部件精密成形制造中有着广阔的应用前景。文章采用刚塑性有限元法对板材冲挤成形工艺进行了模拟,确定了板材冲挤变形的速度场、等效应力场和等效应变场,揭示了板材冲挤工艺的成形特点。基于J.W.Hancock与A.C.Mackenzie提出的断裂判剧和数值模拟分析,预测了板材冲挤成形裂纹产生位置和主要影响因素。通过实验测定板材冲挤成形中裂纹产生情况,验证了模拟分析结果,对于板材冲挤复合成形工艺设计有指导意义。

The combined blanking and extrusion process of sheet metal is a way to form near net shape of thick sheet metal,which has a bright applicable future in the manufacture of the automobile components.In this paper,the rigid-plastic finite element method is adopted to simulate the process,through which the distributions of velocity、effective stress and effective strain are obtained and utilized to reveal the deformation features of the process.Based upon the ductile criterion proposed by J.W.Hancock and A.C.Mackenzie and numerical analysis,the location and influencing factors of fracture are predicted.Meanwhile,the fracture was determined through experiments,which verified the analyzing results.Moreover,this paper provides technical basis for the design of the process.