The granular-media-based thin-wall elbow push-bending process involves filling a tube with granular media and pushing the tube into a die to bend a tubular blank into an elbow shape. By means of the mechanical characteristics of granular filler, an elbow tube with t/D < 0.01 (the ratio of wall thickness to outer diameter) and R/D < 1.5 (the ratio of bending radius to outer diameter) can be formed. To investigate the interaction between thin-wall elbow and granular filler, A 3D FEM-DEM coupling numerical model is developed, which takes into account both the deformation behavior of tubular blank (continuum, finite element method FEM) and mechanical characteristics of granular filler (discrete media, discrete element method DEM). By means of the coupling model, the key forming parameters of an elbow tube such as forming force, wall thickness distribution, wrinkling are simulated and compared to experimental results.

基于颗粒介质的薄壁弯头推​​弯工艺包括向管中填充颗粒介质，然后将管推入模具中，以将管状毛坯弯曲成弯头形状。借助于粒状填充物的机械特性，可以形成t / D <0.01（壁厚与外径之比）和R / D <1.5（弯曲半径与外径之比）的肘管。为了研究薄壁弯头与粒状填料之间的相互作用，建立了一个3D FEM-DEM耦合数值模型，该模型同时考虑了管状毛坯的变形行为（连续，有限元方法FEM）和粒状填料的力学特性（离散介质，离散元方法DEM）。通过耦合模型，肘管的关键成形参数，例如成形力，