Eight-roller Straightening Process Simulation Of Thin-walled Tube And Static Analysis Of The Frame

With the rapid development of national economy, thin-walled tube is sharply rising in demand in industrial and high-tech field. Therefore, the manufacturing precision of thin-walled tube parts is very important. The diameter of thin-walled tube is generally more than 20 times the wall thickness.Its straightening process is the process of elastic-plastic deformation of the shell structure. The straightening problem of thick-walled tube can completely refer to the straightening process theory of solid shaft parts, but it is different from the straightening problem of thin-walled tube. Therefore, people have been trying to solve the problem of thin-walled tube straightening.Firstly, basing on elastic-plastic bending theory and drawing on previous experience in the design of the roller shape, the curve of hyperbolic curve roller shape was drawn by using Matlab and AutoCAD. The curve of roller shape is corrected according to the actual situation. Finally, the 3D model of the roller is created in Solidworks. According to straightening theory, the roller bevel is determined and the straightening speed is calculated. The bending amount of rollers is determined in accordance with the principle of small deformation.The eight-roller straightener is equivalent to the synthesis of a six-roller straightener and a three-roller straightener.The straightening force and straightening bending moment are calculated.Secondly, the eight-roller straightening process of thin-walled tube is simulated by using finite element software-AINSYS/LS-DYNA. The simulation results are post-processed by using LS-PREPOST3.2 (Beta).The contact model of thin-walled tube straightening, as well as the equivalent stress strain contours of biting-into stage, stable straightening stage and straightening completion stage of steel pipe, are. The axial straightness of steel pipe is analyzed after straightening and meets precision requirements. It verifies that the calculated straightening parameters are reasonable and it can conduct the actual straightening of thin-walled tube.Finally, The static analysis for preload frame of eight-roller straightener for thin-walled tube is carried out by using ANSYS. At first, the stress value of frame components is analyzed after loading the pretension, and then the straightening force is loaded. The stress changing of frame components is analyzed and meets the strength requirements. It has guiding significance in the design of frame.