肋骨冷弯加工时克服“旁弯”的理论计算及应用

The Theory Calculation to Overcome the “Vertical Curve” and Its Application of Frame Cold Bended

船体肋骨通常是通过冷弯加工成形的 ,由于大部分肋骨是不对称型材 ,因此在冷弯加工成形时 ,会出现“旁弯”现象 ,这是有碍成形质量的变形 ,必须加以矫正才能进行安装。本文通过力学分析阐述“旁弯”产生的原因 ,以及消除“旁弯”所需的弯曲力矩 ,并进行了实例计算 ,最后提出了在肋骨冷弯机上解决“旁弯”的垂弯装置。

The hull frame often uses the cold bending process to take shape. Since the section of the hull frame is usually not symmetrical, a phenomenon called as “vertical curve” appears during the cold bending process. “Vertical curve” means that the frame is not only curved in the plane XOY but also curved in the plane XOZ. The deformation in the plane XOZ is harmful and is corrected before fitted. By means of the theory of plasticity, the reasons why the “vertical curve” would take place are found out and the formulas used for calculating the moment M y amd M z are given in this paper. The moment M y and M z can be applied to bend the frame and to balance the moment which leads to the “vertical curve”. Finally, a vertical bending device installed on frame bender is put forward, which is practically used in some dockyards.