Research On Dynamics Simulation Of Cylindrical Power Spinning Process

Power spinning process of cylindrical workpieces which synthesizes characters in forging, extruding and stretching is widely applied in national defense and aerospace field. With the development of spinning processing and material industry, higher demands on modeling quality of spinning products are placed at home and abroad. As more materials with different performance and dimension are applied in power-spinning of cylindrical workpieces, technological parameter needs to be reset in the spinning process of new products. The technological parameter is usually set by researchers depending on their working experiences and the design requirements of products. Spinning experiments are conducted for times to adjust the technological parameter according’to the experiment results. Then the technological parameter ultimately is ascertained and used for production. Therefore, money and production time are wasted. On account of the limitation of technological experiments in times of experiments, the final technological parameter is not always the most appropriate one.Setting technological parameter on computers with dynamics simulation and performing simulation experiments can greatly shorten the time of technological experiments and analyze the effects of each technological parameter on modeling) quality of products. The economic cost and times of experiments are unconstrained. Applying dynamics simulation technique to spinning process is playing a guiding role in setting spinning process parameter and it can improve the production efficiency and modeling quality effectively.Even though dynamics simulation has plenty of advantages, a series of spinning experiments are needed to be designed. The setting of technological parameter in each experiment is based on the spinning force. Therefore, calculating spinning force is the key to design a reasonable experiment. At present, Thamasett algorithm is Usually used to calculate spinning force. However, there is great deviation between the calculated values and measured values. Aiming at the problems of stress and spinning force modeling. Thamasett algorithm is corrected and a new spinning force model is built according to the deviation law between calculated values and measured values so as to make up the shortfall of the ignorance of metal accumulation before spinning wheels. In the part of stress, the author applies Hooke’s law, Saint-Venant principle and elastic-plastic theory in the thesis. The stress of cylindrical workpieces is split in radial, axial and tangential direction, and the corresponding equilibrium equations. compatibility equations, boundary condition equations and constitutive equations are established to build the mathematical model of stress. The new spinning force and stress modelings can control technological parameters at a proper level. which is the base of setting reasonable process plans.ANSYS/LS-DYNA software is chosen as an analysis platform based on the metal plastic forming finite element method, the new algorithm of spinning force and stress and the deformation characteristics of materials in the process of modeling. The hypothesis is tested. The establishment of the geometric model of power spinning process of cylindrical workpieces, the division of the grid, the choice of friction model, the setting-up of connection and constraint, the selection of convergence rule and the iterative solution are all researched and the dynamics simulation model of power spinning process of cylindrical workpieces is established.This thesis studies the deformation of cylindrical workpieces in the power spinning process and changes of the spinning force and stress through simulation model. The spinning process experiments are carried out with the same technological parameters. The change rule of spinning force in the modeling process is obtained by electrometry. And defect analysis is done aiming at the defect of spinning products in different technical programs. The reliability of the results of dynamics simulation model is validated from the perspective of process experiments. The impacts of spindle speed and the feed rate of spinning wheels on spinning force, the influences of feed rate on stress, strain, circular degree, nominal diameter and wall thickness tolerance, and the effects of blank dimension on the modeling quality are analyzed. The analyses give researchers a better perspective on the characteristics of spinning technological parameters and provide guidance to the setting of parameters.