Numerical Study On Roll-Box Forming Technique Of Square Steel Tubes

As one of most common section steel tubes, square steel tube is widely applied in various industries. Compared with other non- round steel tubes,It have several advantages such as light weight, high strength, material-saving, easiness to installation, etc. It can not only improve capability of resisting nature damage for structures, but also easily standardized in structural industry. So it is used widely in building,medical equipment, top-grade furniture,automobile,plane,subway,ship-building ,etc. Generally, square steel tubes are manufactured by roll forming process by taking round tube as original material, i.e. by a"round to square"forming process.There are some disadvantages in traditional four rolls forming process to produce square steel tubes, such as mode of deformation, flexibility of manufacture, shortage in driving force. After analyzing characteristics and mechanism of square steel tubes roll forming process, a new forming mode, Roll-box, is introduced for square steel tubes forming in this thesis. In Roll-box forming model, the forming horizontal and vertical rollers are set alternately in the longitudinal direction.In this thesis, key technologies of roll-box forming were researched. In order to study the feasibility of the new mode, a large deformation elastic-plastic FEM model is developed by introducing objective constitutive model of rotational formula into the dynamic explicit finite element method.