轿车后部加强板回弹问题的补偿方法

针对采用DP600高强钢的大众某车型的车后部加强板在进行模具开发时回弹量大、零件形状精度低等问题,开展了零件拉延、修边、翻边、整形的全工艺流程CAE仿真分析,得到了零件的回弹特征,通过采取模具补偿的方案进行回弹控制,最后经试验测量验证改善效果明显.     

Expansion ratio analysis for initial die-face design of panel drawing dies

When the initial die-face of panel drawing dies is designed, the method of expansion ratio analysis (ERA) is usually employed to carry out formability analysis. Traditionally, ERA is performed with the help of geometry and experiential knowledge. Inevitably, design results differ from each other to the extent designers’ experiences vary. This is a rare work in which the authors research ERA by means of numerical simulations and experiments. Some useful rules are found, which can guide engineers in designing the initial die-face of panel drawing dies. ERA is less accurate than numerical simulation. As it locates upriver of panel dies development, its effect is significant. If the initial die-face is found to be acceptable after ERA, the efficiency and accuracy of numerical simulation can be improved greatly in designing the fine die-face and forming process.     

基于Offset技术的汽车覆盖件边界光顺方法

针对模具型面设计过程中处理零件外边界凹入部分的工艺补充的问题,提出一种基于平面多段线Offset技术的零件边界光顺算法。在冲压方向上对零件外边界进行投影,基于滚柱法的原理,给出分段投影轮廓线的距离为R的Offset曲线并以圆弧相连。根据闭合的Offset曲线的自交点判断零件投影轮廓光顺区域,得到的光顺区域端点与空间零件外边界的真实光顺区域端点一一对应。结合零件外边界的几何信息,用NURBS曲线及蒙皮法在已判定的光顺区域构建光顺曲线及光顺曲面。采用Offset技术可以精确找出所有需要光顺的区域,可避免出现细小误差和修正问题,具有一定的鲁棒性。将算法集成到自主开发的冲压成形分析软件KMAS模具型面设计模块,并与Dynaform软件和Pam-Stamp软件的光顺结果相比较,试验表明该算法具有很好的有效性和可靠性。