Impacts On The Cross Section Deformation From Straightening Technology

Pipes are important parts of mechanical devices, they can save material and cost with light weights. Because pipes may produce axial bending and the cross-section deformation during the machinery manufacturing process, we need the straightening process to ensure the quality of the production.After learning a large number of the existed literature, this thesis uses finite element method to calculate and analyze the thin-walled pipe deformation caused by a simple external force. This method is based on metal elastic-plastic mechanics theory, using equilibrium conditions, boundary conditions, the principle of virtual work, kinematics of the thin shell theory. Depend on this method, this thesis figures out several reasons of the thinly walled pipe section’s flattening and the general influence law of the cross-sectional deformation due to the wall thickness, the fulcrum distance, the shape of the indenter by using experiments and simulations.Based on the mechanical properties of the thin-walled pipe fittings, this thesis researches the cross-section deformation of pipe-in-pipe in deep water under pressure, explores the cross-section deformation of pipe-in-pipe on the influence of inner and outer pipe wall thickness. In addition, through simulation we found that pipe-in-pipe deformation can be divided into the whole bending and local bending when we press the radial pressure on pipe-in pipe.