As the development of precise forming, combined with the promotion of the demand on thin-walled net shape parts, the spinning technology is widely applied due to its good forming performance. Ball spinning, as a special spinning process, can be traced to the tube power spinning with rollers. Because of its unique forming characteristics, ball spinning gains more and more attention in aerospace, mechanical and weapon fields. Therefore, research on ball spinning process would be very valuable both in engineering and theory. Based on this background, process optimization and typical defects of ball spinning process of thin tubes were investigated here.
In the dissertation, the principle theory of the Finite Element Method and ball spinning characteristics of thin-walled tubes are systematically studied firstly. A three dimensional rigid-plastic finite element model, which is in accordance with the ball spinning process of thin-walled tube, is established on the platform of DEFORM3D.The contact boundary conditions are discussed to assure the correctness of the key technology of modeling.
Three dimensional rigid-plastic finite element analyses are carried out for forward ball spinning process. The flow rules of the metal as well as the distributions of stress and strain in the deformation zone during the steady deformation of the ball spinning are obtained. In addition, ball spinning simulations under different technical parameters are conducted, and the corresponding influence of process parameters on the formability are also analyzed.
The design of die structure is finished in this dissertation, which lays a basis for the ball spinning experimental research. Comparison and analysis between the results of numerical simulation and experiment date are conducted, which provide theoretical basis for option of the optimal parameters.
Combined with the results of experiment, the reason of some typical defects on tube ball spinning is investigated, and the relevant solutions are also proposed, which are very helpful in design of the production.
修改评论