支管直径大小对T型三通管充液成形的影响

摘要

ABSTRACT:The aim of this work was to study the effect of branch diameter on the hydroforming process of T-shape tube. The finite element model was created in Dynaform. Numerical simulations were executed to analyze the forming process of T-shape tube and compared with the experimental results. With the decrease of branch diameter, the thickness at the end of the main tube increased, and the thickest area of the main tube gradually transferred from back to side. The smaller the branch diameter was, the more upward the thickest area was. The thickness distribution of T-shape tube with smaller branch diameter was more uniform and the thickness variation was more intense. In the first stage of hydroforming, the axial feeding had a more significant influence on the forming of T-shape tube. Increasing the axial feeding of T-shape tube with larger branch diameter could reduce the thinning rate. With the increase of the axial feeding of T-shape tube with smaller branch diameter, the decrease rate of the thinning rate was not obvious, but it could increase the thickening rate. When the branch diameter of T-shape tube was smaller, there was more difficulty in hydroforming, with greater risk of wrinkling and cracking. When the branch diameter was larger, the axial feeding should be increased in the first stage. When the branch diameter was smaller, the axial feeding should be reduced to meet the thinning rate.%目的：研究支管直径大小对T型三通管在充液成形过程中的影响。方法在Dynaform软件中建立了有限元模型，对T型三通管的成形过程进行了数值模拟，并进行了相关实验对比。结果随着支管直径的减小，主管端部的壁厚增大，主管壁厚最厚处逐渐从主管背部转移到主管侧壁处，支管直径越小，壁厚最厚处位置越靠上。支管直径较小的T型三通管的壁厚分布更加不均匀，壁厚变化更为剧烈。充液成形第一阶段的轴向补料量对于T型三通管成形的影响较大，支管直径较大的T型三通管补料量增大有助于减小减薄率；支管直径较小的T型三通管补料量增大，减薄率减小不明显，反而会大幅增加增厚率。结论 T型三通管的支管直径越小，其充液成形的难度越大，起皱和破裂的风险越大。支管直径越大，应增加第一阶段的补料量，支管直径越小，在满足减薄率的条件下需减少补料量。