Study On Numerical Simulation Of High-efficient Spinning Based On Multi-point Adjusting Methodology

High- efficient spinning forming is a novel technology for sheet metal high- efficient forming. It's the organically combine with multi-point forming and the traditional spinning forming technology. Its basic principle: Firstly, dispersing the rigid spinning wheel of the spinning machine into a number of small discrete cell rollers. Secondly, adjusting the relative position of the cell rollers by regulating device, then the small rollers composed of different curves with various curvature, so continuous partial forming for different 3-D surfaces of sheet metal can be realized. Products exploitation cycle can be shorter greatly by this surface forming means, and also reduce the production cost, improve the flexility of product renewal. As compared with traditional spinning machine, high- efficient spinning forming still have other excellences, such as: high quality, flexibility, automatization of product lines, low cost, and intelligence. As a novel and applied forming artifice of sheet metal, high- efficient spinning technology will be fulfil the requirements of aviation, spaceflight and shipbuilding industry more effective.Shaped quality of the sheet metal is easily affected by certain facters during the forming process, for instance: plate thickness, metal stuff, forming rate and forming mode etc. Its machining orderliness can be predominate better by doing research on the equations mentioned hereinbefore, and these tasks are important guidance for 3-D surface forming of sheet metal.In this paper, for studying the influence on the part owing to the above parameters, dynamic explicit finite element software is introduced to simulate the high- efficient spinning forming process of dishing surface. Firstly, establish FEA model of dishing surface in the high- efficient spinning process; Secondly, analyse the forming process and forming characteristics; Finally, set different parameters and study forming orderliness. The main contents and results of the research are as follows:1. The brief introduction of high- efficient spinning formingThe high- efficient spinning technology is the organically combine with multi-point forming and the traditional spinning forming technology. Its basic principle is that sheet metal can be formed by continue local way through the curve of changeable curvature which is composed of several short rollers with highly adjustable, revolving and sway ability themselves and then through short roller's press displacement and friction between rollers and sheet metal. In this paper, we make a simple introduction about the forming principle, forming characteristics, forming methods and application prospects.2. Establishment of FEA model of dishing surface in the process of high- efficient spinning formingThe Explicit Dynamics (LS-DYNA) has been applied for numerical simulation of sheet metal formation. Selecting different simulation units for the course that according to the curved surface features, Cell SHELL163 with BT arithmetic is applied for dishing surface forming; Flexible rollers and sheet metal are respectively defined as rigid materials model and nonlinear elastic materials model on the basis of their different conditions in the course of spinning forming; Constraint conditions, contact status as well as friction problems are determined separately; Make certain the virtual rotating speed and local coordinate system for the flexible rollers in the simulation, establish finite element models for dishing surface.3. Numerical simulation on high- efficient spinning forming process of dishing surfaceNumerical simulation on high- efficient spinning forming process of dishing surface, the main research contents are as follows: Forming traits and stress, strain in distribution of dishing surface; The effect of sheet metal's thickness on the shaping process; The influence of spinning times in the process; Effect of material on the forming quality; Analysis of effect to sheet metal forming process considering spinning rate of flexible rolls etc. Finally, the following conclusions are summarized: The dishing workpiece has good forming effect, the stress distribution is not uniform, some regions don't reach the yield limit ; And the strain distribution is like concentric ring, the central area and the edge region have a larger equivalent strain, and the middle region have smaller equivalent strain; In the process of forming the dishing work-piece is easy to form defects, such as wrinkling, indentation, asymmetry; With the increasing of thickness of the plate, wrinkling that emerging in the process are decreasing, quality of sheet forming becoming better and better; In the identical condition, wrinkling phenomenon and non-uniform distribution of stress and strain were gradually decreased, even disappeared with the increasing of rolling times, shaping results are improving obviously. When the rolling times is 15, the dishing work-piece, which has the radius of curvature R = 300mm and the thickness t=0.5mm, has a good forming effect; Forming effect of steel plate is better than aluminum plate's, its forming force of the unit rolls as well as greater than aluminum when using the sheet metal with different material quality. The forming effect of 08Al steel is better than 2024; With the increase of press amount, the deformation is increasing, and the forming force is greater. Press amount has effect on the quantity of the part. When the press amount is 1.0mm, the dishing work-piece, which has the radius of curvature R = 150mm and the thickness t=2.0mm, has a good forming effect; Virtual speed of flexible rolls have little effect on the equivalent stress and equivalent strain of the piece.4. The numerical simulation of the clamping force in the process of spinningTo research the effect of clamping force in the process, we establish finite element models for dishing surface. The results show that: Under the same conditions, the greater the clamping force, the plate is more easily prone to have defects; If the clamping force is too small, the contact between sheet and rolls will break away, and the plate can not deform.5. The numerical simulation of the forming modeTo research the effect of the forming mode, we establish finite element model for dishing surface. The results show that: The mode of dual group and three-roll is better than the mode of single group and three-roll; The mode of single group and three-roll is better than the mode of single group and two-roll; The mode of dual group and two-roll is better than the mode of single group and two-roll. From the side of forming efficiency, the mode of single group and three-roll is more efficient than the mode of single group and two-roll.