پديد آورنده :
وزيري سرشك، محمد رضا
عنوان :
ارزيابي مدلهاي رفتاري و توسعه مدل آسيب در فرآيند براده برداري متعامد
گرايش تحصيلي :
طراحي كاربردي
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك
صفحه شمار :
يازده، 170 ص.: مصور، جدول، نمودار
يادداشت :
ص. ع. به فارسي و انگليسي
استاد راهنما :
محمود سليمي، محمد مشايخي
استاد مشاور :
محمد رضا فروزان
توصيفگر ها :
مدل ماده , شكل گيري , جدايش براده , رفتار پلاستيك ماده , تاريخچه و مسير كرنش
تاريخ نمايه سازي :
15/2/1389
استاد داور :
محمد رضا موحدي، فخرالدين اشرفي زاده، مهران مرادي
كد ايرانداك :
ID299 دكتري
چكيده فارسي :
به فارسي و انگليسي: قابل رؤيت در نسخه ديجيتال
چكيده انگليسي :
Evaluation of Material Constitutive Models and Development of Damage Model in Orthogonal Machining Process Mohammad Reza Vaziri Sereshk mrvaziri2000@yahoo com March 9 2010 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran 1st Supervisor Mahmoud Salimi1 salimi@cc iut ac ir 2nd Supervisor Mohammad Mashayekhi mashayekhi@cc iut ac ir Advisor Mohammad Reza Forouzan Department Graduate Program Coordinator Mahdi Keshmiri Abstract Machining operations involve extremely high rates of plastic deformation This study presents some insight to this subject by systematic evaluation of the relative performance of six fracture models to identify the most suitable fracture criterion for chip separation In addition a new algorithm is developed to calculate constants of the damage models It is demonstrated that due to different failure mechanism a unique fracture model cannot be the representative of crack generation in all machining zone It is found that predictions of FE approaches without implementing damage models for strains and temperatures within the deformation zones are not satisfactory and the predicted resistance of workpiece material to cutting is unrealistically high It is demonstrated that the first predominant factor governing the material flow stress is strain hardening and strain rate and temperature do not counterbalance the effects of each other Therefore suitable mathematical equation for material model in machining should include their effects separately to implement the effect of velocity of process and external heat source friction It is demonstrated that for b c c metals loading path history plays no significant role in changing the flow stress In addition extrapolation of these material model equations is possible Key Words Cumulative damage fracture model Material constitutive model Chip separation formation Finite element simulation Introduction Many aspects of machining such as chip formation cutting forces temperatures and surface integrity of machined products are significantly affected by the mechanical properties of materials On other hand machining operations involve intense physical conditions including extremely high rates of plastic deformation up to 106 S 1 generating high temperature up to 1200 C in machining of steel The resulting complex and highly nonlinear phenomena make them relatively difficult to model Several leading commercial codes offer a number of different and sophisticated fracture options At same time no guidance is given for the users to identify suitable fracture criterion for a particular application and to determine the fracture parameters for different materials Rosa et al 1 evaluated normalized Cockcroft Latham C L ductile fracture model 2 as a tensile cracking criterion and shear work per volume specific distortional energy criterion as shear cracking criterion in the updated Lagrangian UL approach They concluded that the specific distortional energy is an appropriate criterion for evaluating the ductile damage and the onset of separation ahead of the cutting 1 Department of Mechanical Engineering Isfahan University of Technology Isfahan Iran
استاد راهنما :
محمود سليمي، محمد مشايخي
استاد مشاور :
محمد رضا فروزان
استاد داور :
محمد رضا موحدي، فخرالدين اشرفي زاده، مهران مرادي
