不锈钢管件滚弯成形工艺的有限元模拟

Numerical Simulation and Nonlinear Dynamic Analysis of the Roll-Bending Process for the Stainless Steel Tubes

应用ANSYS有限元分析软件中的LS-DYNA求解器,对薄壁不锈钢管件弯曲成形过程进行了弹塑性数值模拟.通过对管件弯曲角度的试验结果与模拟值的对比分析,证明了建立管件有限元模型的正确性.在此基础上对管件滚弯过程的模拟结果进行了应力应变分析,揭示了其成形时的塑性变形流动规律及其对管件质量的影响.研究结果表明:薄壁不锈钢管件弯曲冷成形的主要失效形式是内侧部分的起皱和外侧部分的失稳;管件弯曲内侧等效应变和壁厚变化呈跳跃式条状分布,是管壁起皱变形的前兆,管件弯曲外侧的壁厚减少导致其弯曲刚度降低,是管壁失稳变形的原因;最大等效应变和等效应力的部位出现在管件弯曲区域的、与滚动轮和旋轮接触部位,其弯曲成形后,部位的应力值逐渐减小,且沿两端方向应力逐渐减少.

The elastoplastic numerical simulation was proceeded in the Thin-Wall Stainless Steel Tubes bended forming process using LS-DYNA solver of ANSYS finite element analysis software. The analysis of the simulation value compared with the test results of pipe fittings bended angle proved the validity of the Finite Element Modeling the tubes bended forming process. On this basis, the stress-strain of the tubes bended forming process were studied, meanwhile,the basic law of plastic deformation and its effect on the tubes bended processing quality was posted. The results shows that：the medial surface wrinkling and the lateral surface unstability are the main failure form of the thin-wall stainless steel cold bending forming. The premonition of the tube wall wrinkled is the tube bending media equivalent strain and the wall thickness variying in skip strip distribution. And the reduced tube bended lateral wall thickness led to the bending rigidity decreasing, this may be the cause of tube wall destablizing and deforming. The place of the maximum equivalent strain and stress emerged in the contact site of tube bended area with the rolling wheel and the spinning wheel, in which the stress reduced gradually and toward the tube two terminals.