Research On Accurate Spin-forming Of A U-shaped Cross Section Frame Ring For Launch Vehicle Application

By supporting the longitudinal stringers,the intermediate frame of the launch vehicle improves the stability of the stringers and increases the radial stiffness of the structure,thereby improving the bearing capacity of the cabin structure.The intermediate frame is composed of a cover plate,a U-shaped section frame ring and a Z-shaped frame.In order to ensure the cooperation between the U-shaped section frame ring,the skin and the cover plate,there are strict requirements on its dimensional accuracy.Aiming at the problem of insufficient precision in the traditional forming process of the frame ring,aiming at accurate forming,this paper proposes a new spinning process to form the U-shaped cross-section frame ring,and studies the deformation mechanism and accuracy of the concave and convex flanging spinning.The regulation mechanism provides a certain reference for the precise forming new technology of this type of ring segment components.The main research contents of this paper are as follows:(1)According to the structural characteristics and plastic forming theory of the target workpiece,design a new spinning process plan,theoretically analyze the deformation mechanism of the frame ring during the spinning forming process,and design the blank size according to the geometric mapping relationship between the blank and the workpiece.(2)The MSC.Marc finite element software platform was introduced to establish a frame ring spinning simulation model,and preliminary simulations were carried out for the concave and convex flanging of the frame ring,and the stress and strain distribution and material flow during the forming process were studied.Dimensional error and its forming mechanism,and an improvement strategy is proposed.(3)Design the wheel trajectory from different angles,and explore the influence of different wheel trajectory schemes and key process parameters(rotor fillet radius,feed rate)on the quality of the frame ring spinning.After optimizing the process parameters There is still a small amount of springback,and a general-strong composite spinning forming scheme based on springback control is proposed,and the optimal trace offset δ is determined to ensure that the deviation of the section profile is controlled within the required range.(4)Design the frame ring spinning experiment platform based on the double-column vertical spinning platform,and carry out experiments on the process plan before and after optimization.The results are consistent,which verifies the correctness of the theoretical analysis and the finite element simulation model.