Thin-walled bent tubes with small bending radius are one of the key components used in airspace and aerospace launch vehicles and various electrical equipment. Traditional forming technology for such bent tubes is the welding of two stamped half bends, which cannot meet the high reliability demand anymore, so forming technology for the seamless bends becomes an imperative requirement. This paper presents a new push bending method with granular media filler for thin-walled tubes with small relative bending radius. The pressure distribution of the granular system is investigated by discrete element method (DEM). The bending deformation strengthening is the key advantage of the granular system in preventing tube forming defects especially wrinkling. In addition, the effects of the particle diameter, internal friction of the granular system and the counter-pressure on the internal pressure distribution are explored. Tubes with large diameter, thin-wall thickness, and small relative bending radius were formed, which validates the positive role of granular media on improving wrinkle resistance during bending. All these results indicate that granular media as a filler provides new opportunities for bending thin-walled tubes with small relative bending radius.

具有小弯曲半径的薄壁弯曲管是空域和航天运载火箭以及各种电气设备中使用的关键组件之一。这种弯管的传统成型技术是两个冲压半弯头的焊接，这已经不能满足高可靠性的要求，因此无缝弯头的成型技术成为当务之急。本文提出了一种新的带有颗粒介质填料的推弯方法，用于相对弯曲半径较小的薄壁管。采用离散元法（DEM）研究了颗粒体系的压力分布。弯曲变形的强化是粒状系统在防止管形成缺陷（特别是皱纹）方面的关键优势。另外，粒径的影响 研究了颗粒系统的内部摩擦和内部压力分布上的反压。形成了具有大直径，薄壁厚度和较小相对弯曲半径的管，这证实了粒状介质在改善弯曲过程中的抗皱性方面的积极作用。所有这些结果表明，粒状介质作为填料为弯曲相对弯曲半径较小的薄壁管提供了新的机会。