شبيه سازي فرايند درزجوش مقاومتي در ورق هاي فولادي و تحليل شكست آن

چكيده انگليسي :

Simulation of resistance seam welding process and that fracture analysis Kazem malekipour k malikipour@me iut ac ir Date of Submission 05 07 2012 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Dr Mohammad Reza Forouzan forouzan@cc iut ac irAbstractDevelopment of technology has to offer several connection methods such as welding sewing sheets solder tothe owners of great industries Each of these methods have advantages and disadvantages and their specificapplications Mobarakeh Steel Company has used resistance welding to connect the coils of yarn sheet to maintaincontinuity of its production line Although welding is one of the easy ways to connect the two sheets but also hasdisadvantages For example hot and cold cracks created during the welding process the sheets are prone to rupture In addition residual stresses from resistance welding reduces the load carrying capacity of sheet and Accelerate thegrowth of cracks generated during resistance welding In this project in order to investigate effect of resistancewelding on the failure of sheet resistance seam welding has been simulated in the analytical software This processis an electrical thermal mechanical metallurgical process so failure Investigation is difficult by experiment Inthis process simultaneously applying heat and pressure cause the connection between the two sheets Resistancewelding is often done As spot welding therefore most researchers have focused on resistance spot welding Andsimulation of resistance seam welding hasnot been done To correct modeling of this process resistance weldingshould be fully investigated Contact surfaces treatment must be considered in order to correct modeling ofresistance welding process To simulate resistance seam welding process the element with temperature displacement and electric potential degrees of freedom is required because analytical software havnt element withtemperature displacement and electric potential degrees of freedom process simulation program has written inpython language in abaquse This program is doing thermomechanical and electrothermal analysis at time intervals0 0007 sec In each step of the simulation Electrode moves forward 0 5 mm In electrothermal analysis weldedsurfaces and contact surfaces can be found and these surfaces are introduced to model Another task of this programis to apply the temperature field obtained from electrothermal analysis to the thermomechanical model No similarwork in resistance seam welding simulation has been done so validation of above program has been done bysimulation of resistance spot welding and compare its results with results of other researchers Simulation ofresistance seam welding results showed that transverse residual stresses generated within the sheet is negligible incomparison with longitudinal residual stress Finally effect of deformation of sheet due to resistance seam weldingon propagation of crack in the sheet has been studied by extended finite element method Also to closer look onpropagation of crack in resistance seam welded sheet crack growth phenomena has been evaluated by simple tensiletest In order to observe the effect of resistance seam welding on crack growth in specimens the initial cracks invarious areas of the samples was created Key wordsResistance welding Electrothermal Thermomechanical Residual stress Fracture Crack

مالكي پور، كاظم

شبيه سازي فرايند درزجوش مقاومتي در ورق هاي فولادي و تحليل شكست آن

جوشكاري مقاومتي , مقاومت تماسي , تنش پسماند , ترك