Analysis Of Main Drive System And Simulation Of Multi-clamps Stretching Based On120MN Stretcher

Abstract:In the field of aerospace, large size aluminum alloy thick plate is widely applied to the manufacturing of whole structure, which requires high machining accuracy. But processing deformation is one of the outstanding problems in the manufacturing process. However, the quenching process is used to improve the plate mechanical properties, then, residual stress will be produced. The residual stress is a major cause of machining deformation. Pre-stretching process can effectively reduce residual stress.120MN stretcher is the current domestic biggest tonnage equipment, which is developed to stretch large size aluminum alloy thick plate. So it has important practical significance to carry out the system analysis and design of120MN stretcher, and research the characteristics of residual stress in the pre-stretching plate.First, this paper introduced the research background and the research status of the stretching process and stretcher technology at home and abroad, and put forward the research method and research content of the paper.Second, the mechanical structure characteristics of stretcher were summarized. According to the requirements of the120MN stretcher, the main drive hydraulic system was designed and analyzed in principle. And the key components of the main servo tensile system were selected.Third, according to the structure of main stretch drive system, it determined that synchronous control strategy adopts PDFF control combined with PID cross coupling control. The single cylinder and double hydraulic cylinder coupling system mathematical model were established, which helped to obtain the proper control parameters. It used MATLAB/simulink software to simulate and found that the system control accuracy is relatively high, and the displacement synchronous deviation is only related to the partial load, having nothing to do with the stretching speed. At the same time, the maximum safety partial load was gained. Fourth, the FEA model of multi-clamps stretching for aluminum alloy thick plate on120MN stretcher was set up based on MSC.Marc. From the angle of residual stress reduction and the strip shape straightening, it was proved that using13couples of clamps is reasonable; the clamps sliding was explored, which found that the clamps at the edge of the jaw and the end of the moveable head are easier to skid; the influence rule on processing cutting length and jaw load was acquired when clamps were in different failure states.Finally, through the simulation experiment, the distribution of residual stress was analyzed when the plate was quenched and pre-stretched by overall clamps and discrete clamps. It verified the effectiveness of the finite element model of the multi-clamps stretching.