پديد آورنده :
مشايخي، محمد
عنوان :
گسترش سه بعدي آسيب در مواد شكل پذير
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك
صفحه شمار :
شانزده، 165، [II]ص.: جدول، نمودار
يادداشت :
ص. ع. به فارسي و انگليسي
استاد راهنما :
سعيد ضيايي راد، جمشيد پرويزيان
استاد مشاور :
محمود سليمي
توصيفگر ها :
آسيب نرم , پتانسيل ترموديناميكي , آلگوريتم حل , فرآيند كله زني
استاد داور :
محمود فرزين، محمدرضا فروزان، حسين حسيني تودشكي، اميررضا شاهاني
كد ايرانداك :
ID155 دكتري
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتال
چكيده انگليسي :
AbstractIn this thesis the continuum damage mechanics framework for ductile materialsdeveloped by Lemaitre is validated experimentally and numerically A fullycoupled constitutive elastic plastic damage model is developed and implementedinside the finite element commercial code ABAQUS The main advantage ofdeveloping a user subroutine inside a commercial FE code is the access to a widerange of element types material models and other facilities such as efficientequation solvers The model is based on a simplified Lemaitre ductile damagemodel in which the return mapping requires the solution of only one scalar non linear equation The present model is verified by solving various numericalexamples in two and three dimensional solid elements An experimental procedure to identify the damage parameters under triaxial stressconditions is proposed A local crack growth criterion based on the criticaldamage parameter is proposed the validity of this criterion is examined bycomparing the result of the simulation with the experimental results on standardthree point bending and compact tension tests The critical load at the initiation ofthe crack growth and the fracture toughness JIc are predicted These numericallypredicted values comply favourably with the experimental results Crack closure effects have a strong influence on damage evolution The efficientimplementation of a modified Lemaitre model is described The accuracy of thecomputational model developed for the analysis of the material degradation isverified for bulk metal forming processes The central burst defects inaxisymmetric cold extrusion are predicted numerically and the effects of variousprocess parameters e g diameter reduction ratio die angle friction coefficientand material ductility on the central bursts occurrence are investigated
استاد راهنما :
سعيد ضيايي راد، جمشيد پرويزيان
استاد مشاور :
محمود سليمي
استاد داور :
محمود فرزين، محمدرضا فروزان، حسين حسيني تودشكي، اميررضا شاهاني
