مطالعه تجربي و شبيه سازي المان محدود شكل دهي بيلوزهاي دو جداره فلزي به روش هيدروفرمينگ

چكيده انگليسي :

Numerical and Experimental Investigation on Forming of Two ply Metal Bellows by Hydroforming Mehdi Ebad Sichani m ebad@me iut ac ir Date of Submission 21 September 2014 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Mahmoud Farzin farzin@cc iut ac irAbstractExpansion joints are the most basic parts of piping systems that are used in various industries such aspowerhouses petrochemical and aerospace industries The expansion joint is used for absorption ofmechanical and thermal displacements in piping systems Bellows is the main part of an expansion joint Bellows are essentially flexible elements of expansion joints These are usually made from austeniticstainless steels that show good weldability formability creep and corrosion resistance strength and fracturetoughness The bellows can be made by various methods such as hydroforming punch and roll formingmethods In hydroforming a tube is placed in a hydrolic press or bellows forming machine Circularexternal die ring of suitable countour are placed outside the tube at longitudinal intervals approximatelyequal to the developed length of the completed convolutins The tube is filled with a medium such as waterand pressurized until circumferential yielding occurs this forming operation continues with a simultaneascircumferential yielding and controlled longitudinal shortening of the tube until the proper configuration isobtained Individual or multiple convolutions may be formed by this method Depending on the bellownconfiguration several partial forming steps with intermediate heat treatment may be required Reinforcedbellows may be formed by utilizing external reinforcing rings that act as part of the forming dies Aftercompletion when the dies are removed the rings remain as an integral part of the bellows In this thesisfirst explains various types of expansion joints and their application Then past research on bellows arereviewed In the next chapters of this thesis various forming method of bellows are described Thenattention is paid on hydroforming method of metal bellows and effective parameters on this method arefocused In the present work the latter half processes including the tube bulging folding and springback areanalyzed consistently using the FEM The main objective of this study is to find the effect of processparameters on the one layer and two layer metal bellows properties Parameters such as the geometry anddimensions of bellows die course and pressure of forming For this purpose two samples of single layerand double layer Bellows were made The finite element model has been used to simulate hydroforming ofbellows with ABAQUS Explicit 6 10 and at the end the results were compared with those made Themodel has been confirmed by experimental The simulation results showed good agreement withexperimental test Keywords Bellows Expansion Joint Hydroforming Finite Element Method

عباد، مهدي

مطالعه تجربي و شبيه سازي المان محدود شكل دهي بيلوزهاي دو جداره فلزي به روش هيدروفرمينگ

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