助推装置对数控绕弯塑性变形作用机理的模拟研究

he push assistant device exerts the axial pushing force to the bending tube to improve the bending flow state of materials, which has been widely used in aviation and aerospace industries for tight requirements of bending tube components. But the effects mechanism of the device on the NC plastic bending behavior and its interactive influence laws on wrinkling instability, thinning degree and cross section distortion degree have not been obtained until now, which has restricted its application potential for thin-walled tube bending process with large diameter and small bending radius and blocked the development of the advanced plastic forming process greatly. In the study, based on the analysis of the forming characteristics and the functions of the push assistant device, four possible matching patterns of pressure push assistant and boost device and five kinds application methods are also proposed, the pushing assistant factor (the ratio of the push assistant speed to the bending speed) are put forward to indicate the pushing assistant level and the quantitative index is also selected to estimate the pushing effectiveness of various pushing assistant level. Then the 3D elastic-plastic FEM model of the process has been established using ABAQUS/Explicit code, including bending process, balls retracting and unloading process, which is used to get the best mode of action of boost device. And the effects mechanism of three different matching patterns on the plastic bending behaviors are deeply investigated.