抗凹性的应变设计及合理充液预胀量的确定

抗凹性是评价汽车覆盖件性能的重要指标。采用理论分析方法,研究成形件等效应变、变形模式与静态抗凹性载荷的关系,并以双相钢DP的成形极限图为基础,描绘了二维应变图形内的抗凹性极值线;通过分析双相钢平底筒形件充液拉深成形,确定合适的充液预胀量,使得静态抗凹性载荷最大。结果表明,静态抗凹性载荷受变形模式和成形件等效应变综合影响,当主应变比-1β≤1时,静态抗凹性载荷存在极值,即在二维应变图形中存在一抗凹性极值线。抗凹性极值线可作为试件应变设计的一种基准,采用此方法可得到抗凹性最优的试件。

Strain design for a higher static dent resistance and determination of pre-bulging amount on hydrodynamic deep drawing

Dent resistance is an important index of material selection of outer panel.The dent resistance of parts was calculated theoretically.Extreme value line of static dent resistance in 2D strain diagram to DP340/590 was obtained.Based on this result pre-bulging amount on hydrodynamic deep drawing was determined.The results of the investigation show that static dent resistance is influenced by the modes of deformation and equivalent effective strain of the formed part.When the strain ratio β is in the range of-1～1,the static dent resistance load is maximum,so there is a extreme value line of static dent resistance in 2D strain diagram.Therefore extreme value line of static dent resistance can be used for strain designing,corresponding to the best static dent resistance of the formed parts.