The meshing method is applied to the placement track planning of S-shaped inlet model. Namely, CAD software model of inlet is meshed by using UG meshing generator and the meshing data is created. Based on these data, the topology relation between meshing element and nodes is set up. The normal vector of placement track and track points are calculated in each meshing element. The simulation test shows that this method has some performances such as high speed program performing, the smooth curve of placement track, no mutation of track and so on. So this method has certain application value in engineering. It is put forward to develop a meshing tool for the track generation by using the secondary development function of UG.

Based on plastic mechanics total strain theory, big diameter thin-walled tube bending forming is researched by assuming that only axial stress and strain in every fiber layer exist during tube bending process. The strain calculation equations of tube bending process are created by assuming the function of neutral layer offset angle and cuneiform angle with the angle coordinate. Then the stresses are gained by the relation of strain and stress, and the contact pressure and friction between die and tube are obtained through the integrating of stress on section and the force equilibrium in differential element. Outside force is calculated through the integrating of inner force on boundary. At last the coefficient of the function of neutral layer offset and cuneiform angle in bending segment are calculated through the force equilibrium equation and energy equilibrium equation. Thereby the springback angle is calculated and the infl uence law some process parameters to springback is analyzed.