中文摘要：

针对变截面辊弯成形过程中凸弧受压失稳起皱问题，利用改进后的C-B起皱预测准则和有限元仿真技术，计算起皱因子以评价板料凸弧各处起皱发生的难易程度，生成起皱云图以观察材料各部分的稳定状态并预测可能出现起皱的部位。根据此准则，通过正交实验研究板厚、圆弧半径、边腿高度和圆弧圆心角对起皱的影响规律，为修改辊弯成形工艺和模型提供依据。有限元仿真模拟结果与理论推导数据吻合良好，证明了起皱准则的有效性和精确性。

英文摘要：

In order to research the wrinkling occurred in the sheet＇s convex arc of roll forming with variable cross-sec- tion, the C-B wrinkling criterion used in the prediction of flange wrinkling was changed specially. Based on the new C- B wrinkling criterion, a special wrinkling factor was put forward to evaluate the wrinkling extent and a wrinkling evalu- ation factor fringe was output from the finite element simulation to show the whole sheet＇s steadystate and predict the onset of wrinkling. According to the wrinkling factor, the influences of sheet thickness, arcradius, flange height and centralangle on the wrinkling were researched to give some ideas to the process design. The experimental result of the finite element simulation was exactly the same as the conclusion which was gained from the theoretical derivation. It is proved that the new C-B wrinkling criterion is suitable to predict the roll forming wrinkling.