بررسي تجربي و عددي هيدروفرمينگ لوله هاي دو پله اي مسي با مقطع مربعي در قالب هاي متحرك

چكيده انگليسي :

68 Experimental and Numerical Study of two Step Copper Tubes Hydroforming with a Square Cross Section in the Moving Die Hossein Ghorbani Menghari h ghorbanimenghari@me iut ac ir Date of Submission 2013 01 16 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Hassan khademizadeh hkhademyza@cc iut ac ir Abstract predicting and preventing defects like wrinkles and ruptures from happening are such a important issue in hydroforming area these flaws depend on initial and final pressure and also longitudinal feeding during process therefore it is so important to select an appropriate direction to apply the pressure proportional to the longitudinal feeding manufacturing specimen with its corners completely filled along side uniform thickness distribution is considered as another crucial issue in tube hydroforming process in order to manufacture tubes with their corners filled an increase on pressure imposed to the tubes is needed in conventional dies which results in tear at the corner regions of the tube sample the new die designed can be used for manufacturing two steps box shaped tubes using four moving bush to create completely filled steps can be regarded as an advantage of the new die in comparison with the conventional dies the movement of the bushes causes the specimen to move while being fed which eliminates the effect of friction between the sample and the die and also the gap between the two is diminished to almost zero which ultimately results in manufacturing of a two steps box shaped tube with its corners completely filled in order to produce the tube using new die set firstly after putting the specimen in the die it is sealed by the O Rings installed at the bottom of the punches subsequently oil is injected with high pressure via the central hole of the top punch thereafter when the tube is barrel shaped the top punch comes down using a press set to get close to the bottom punch the movement of the top punch causes the two small top and bottom punches get closer simultaneously until the fist step is formed the next stage is reducing the pressure to zero and moving the two box shaped bushes out regarding the final feeding and then the pressure is heightened to its final level then the four defined bushes move toward each other as the top punch is getting closer to the bottom punch until the second step is formed In this research corner filling in two stepped tubes is studied using a new multistage hydroforming die The proposed die was simulated and filling of the die cavity was investigated The finite element software ABAQUS 6 11 has been used for simulation In order to verify the simulation results the new die of two stepped tube was manufactured and then experiments have been performed on it The results of the experiments verified the simulation results It was shown that by using the new die parts with sharp corners could be produced The simplicity of the die and the low internal pressure are among the advantages of this die Thickness distribution was also examined by FE simulation and via experiments and it is shown that a better distribution could be obtained by the proposed die set Keywords Tube Hydroforming Several Steps Tube Finite element simulation Wrinkling PDF created with pdfFactory trial version www pdffactory com

قرباني منقاري، حسين

بررسي تجربي و عددي هيدروفرمينگ لوله هاي دو پله اي مسي با مقطع مربعي در قالب هاي متحرك

هيدروفرمينگ لوله , لوله هاي پله اي , شبيه سازي اجزاي محدود , چروكيدگي