| Hydroforming technology is a whole complex plastic forming technology. T-Tube hydroforming technology offers its several advantages:high accuracy,low quality,low error of the assembly,low cost,etc.and it will be having great application value and development prospects in aerospace, automotive, and other fields. In the actual production, considering some factors of the deformation of tube blank, long design cycle, complex mold design repairing to the person complex factors, Hydraulic forming die special parametric integration system has become a way of convenient, improving the efficiency of design for t-tube. Therefore, this dissertation uses the method of simulation combined with experimental study, with the parameterized design of the die,for the specifications of ?32mm×1mm LF2 M aluminum alloy tube, carry out basic research. The study mainly concentrates in five aspects:(1)For accurate measurement of diameter of 32 mm, wall thickness of 1mm material properties of LF2 M aluminum alloy tube, by means of tensile test of constant speed displacement method. On the one hand dissertation get material plastic strain ratio R value by not breaking tensile test; and on the other and by getting the true stress strain curve graph fitting material strain hardening index n value and intensity coefficient K value.(2)In order to find the law about effect of t-tube hydroforming parameter and rules about the thickness of the forming. Dissertation study the t-tube hydroforming by the finite element software. It is showed that with the continuous increase of friction coefficient, branch height is reduced and the pipe thickness difference is rising; with the continuous increase of fillet radius, branch height is increased and the branch pipe wall thickness difference is reduced.The reasult of the distribution of the branch pipe thickness is:In the center top branch angle, down along branch pipe the thickness decreases gradually,and the thickness of fillet area reach the maximum.(3)In order to find suitable internal pressure loading path, dissertation also has coMPared different methods of internal pressure load to single linear loading paths.It is showed that in that internal pressure loading paths when the maximum displacement of left, right is 20 mm, dissertation designs internal pressure loading path through coMParison and analysis of different internal pressure loading path after simulation. In the loading path, dissertation simulated successfully meet the effective branch height is 25 mm, the minimum thinning rate of no more than 25% of T-tube hydroforming. It is also showed that when the feed rate is determined, given suitable initial internal pressure is beneficial to avoid wrinkles forming process; too large the pressure inside the terminal value is will lead the break of the top branch; internal pressure is the important role of branch height controlling in the late forming.(4)In order to find a way to improving design efficiency, shorten design cycle and convenient for the researchers studying other diameter t-tube hydroforming, dissertation uses the method of parametric design in the CAA and VC++ as the development tool to achieve the creation of t-tube hydroforming die design system.(5)Dissertation uses special tube hydroforming equipment for experimental verification. It is showed that t-tube pipe single linear internal pressure loading path in the initial inner pressure forming, not only with the simulation results are consistent, and high forming efficiency, good forming quality, meet the standards of the T-tube forming. |
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