6751

6293

كارشناسي ارشد

طراحي كاربردي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1390

نه، 97ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

محمدرضا فروزان

احمد كرمانپور

17/3/91

محمود فرزين، احسان فروزمهر

1396/10/06

كتابنامه

مكانيك

مهندسي مكانيك

ID6293

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Investigation into Welding Process and Residual Stress Relieve in Fabrication of Oil Storage Tanks Hamzeh Almokdad hamzehmokdad@gmail com Department of Mechanical Engineering Isfahan University of Technology Isfahan Iran Degree M Sc Language PersianAssoc Prof M R Forouzan forouzan@cc iut ac irAbstract Large capacity storage tanks are widely used in many industries particularly in theprocessing plants such as oil refinery and petrochemical industry They are used to store amultitude of different products such as raw material and finished products Prediction ofthe residual stresses is of the most important problems in the tanks manufacturing One ofthe most pronounced effects of residual stress is to accelerate or in some cases retard crack growth in structures subject to cyclic loading This dissertation presents numerical study of multi pass welding and thermal stressrelief treatment of an oil storage tank plate specimen the welding phase contains twoparts heating up part and cooling part In the first part the material is heated to its liquidstemperature In the cooling part it is cooled down to the ambient temperature This leadsto develop high residual stresses in weld zone i e fusion zone and heat affected zone Thethermal stress relief treatment phase for a finite time interval the weld zone is heated upto such a high temperature that activates creep mechanism in the material This is one ofthe most effective ways to relief welding residual stresses Finite element method is employed to model and analyze both the welding andthermal stress relief processes for multi pass butt welded AISI low carbon steel of anoil storage tank plate specimen The main goal of this dissertation is to investigate theeffect of welding parameters such as heat input welding speed wall thickness andpreheating In the second part the effect of thermal stress relief treatment parameters including holding time and temperature on the distribution of welding residual stressesare investigated In this simulation sequential coupled thermal mechanical model isdeveloped in welding simulation and thermo physical and mechanical properties ofmaterial used for welding and thermal stress relief treatment simulation are depending onthe temperature In the thermal analysis of welding phase the weld heat source modelbased on the Goldak s double ellipsoid power density distribution was applied After thethermal analysis the mechanical analysis is performed Then the stress distribution of thespecimen has been transferred to a second analysis for stress relaxation modeling Nortonlaw is used to investigate creep in stress relief process Whole the processes are simulatedon ANSYS commercial software developing related ANSYS codes Keywords Welding simulation Residual stresses Heat source model Thermal stressrelief Stress relaxation Creep Holding time and temperature

محمدرضا فروزان

احمد كرمانپور

محمود فرزين، احسان فروزمهر