板料粘性介质胀形过程应变速率变化的模拟研究

ANALYSIS OF STRAIN RATE VARIATIONS DURING VISCOUS PRESSURE BULGING OF SHEET METAL

采用半固态、具有应变速率敏感性的粘性介质作为板料软模成形传力介质， 这种粘性传力介质的抗力可随板料发生局部变形而迅速增加， 建立起适应于板料变形的压力， 对提高板料成形性十分有益。本文针对板料粘性介质胀形， 采用有限元模拟方法研究了板料与介质应变速率变化， 模拟结果显示介质应变速率与相接触的板料应变速率是一致的， 解释了粘性传力介质变形抗力 “自适应”于板料变形的原因。

The semi solid and strain rate sensitive viscous medium is adopted as pressure carrying medium of flexible die.Resistance of this viscous medium increases rapidly as the local deformation of the sheet metal occured and it is favorable to increase formability.In this paper,the variations of sheet metal and viscous medium strain rate distribution during viscous pressure bulging has been reseached by FE simulation.The simulation results show that strain rate distribution of viscous medium varies in consistent with it of sheet metal in the contacting surface,and explain that deformation resistance of viscous medium varies adaptively to sheet metal deformation.