中文摘要：

法兰起皱、翘曲等失稳缺陷是影响薄壁封头精密旋压制造的重要因素。运用三维有限元软件MSC.MARC模拟大减薄率薄壁半球形封头扩径旋压过程,获得了薄壁半球形封头的壁厚及减薄率对薄壁半球形封头旋压失稳的影响规律。结果表明,壁厚越小、减薄率越大,薄壁半球形封头越容易产生法兰起皱、翘曲等失稳缺陷。提取仿真结果中的周向应力数据,分析了周向应力与法兰失稳之间的关系,得到最大周向压应力为法兰起皱失稳临界应力,并通过旋压实验进行了验证,从而为研究薄壁封头的稳定精密旋压提供理论参考。

英文摘要：

Flange wrinkling and warping or other unstable defects are the important factors affecting the precision spinning of thinwalled heads.The 3D-FE software MSC.Marc is applied to simulate the process of thin-walled semi-spherical head with diameterexpanding spinning at a high thinning rate,and the influence of the thickness and thickness reduction ratio on the spinning instability of thin-walled semi-spherical head is obtained.The result shows that,when the thickness is smaller and the thinning ratio is larger,the thin-walled semi-spherical head is more prone to wrinkling,warping or other unstable defects.In order to further study the instability mechanism,by extracting the circumferential stress of the simulation results,the laws of the circumferential stress are analyzed,and the buckling critical stress is obtained,viz.,the maximum circumferential compressive stress.And it is verified by the spinning experiment,and the results provide theoretical reference for stable precision spinning of the thin-walled head.