پديد آورنده :
بادنوا، حجت اله
عنوان :
مدل سازي غير محلي رفتار ترمو - مكانيكي آلياژهاي حافظه دار به روش گراديان ضمني
گرايش تحصيلي :
طراحي كاربردي
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده مهندسي مكانيك
صفحه شمار :
سيزده، 165ص.: مصور
استاد راهنما :
محمود كدخدايي، محمد مشايخي
استاد مشاور :
بيژن برومند
توصيفگر ها :
رفتارهاي ناپايدار , اجزاي محدود , كوپلينگ دمايي
استاد داور :
غلامحسين لياقت، جمال ارغواني، حميد هاشم الحسيني، عباس قايي
تاريخ ورود اطلاعات :
1395/04/26
كد ايرانداك :
ID899 دكتري
چكيده انگليسي :
A non local implicit gradient enhanced model for thermo mechanical behavior of shape memory alloys Hojjatollah Badnava Ha badnava@me iut ac ir Jan 28 2016 Department of Mechanical EngineeringIsfahan University of Technology Isfahan 84156 83111 IranMahmoud Kadkhodaei kadkhodaei@cc iut ac irMohammad Mashayekhi mashayekhi@cc iut ac irBijan Boroumand boromand@cc iut ac irDepartment Graduate Program Coordinator Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 IranAbstractIn this thesis a gradient enhanced 3 D phenomenological model for shape memory alloys using the non local theory is developed based on a 1 D constitutive model The method utilizes a non local fieldvariable in its constitutive framework with an implicit gradient formulation in order to achieve resultsindependent of the finite element discretization An efficient numerical approach to implement the non local gradient enhanced model in finite element codes is proposed Based on the implicit radial returnscheme a robust integration scheme is proposed using which the model is implemented in ABAQUScommercial finite element code through a user element subroutine UEL The model is used to simulatestress drop at the onset of transformation and its performance is evaluated using different experimentaldata Potential of the presented numerical approach in eliminating mesh dependent simulations isvalidated by investigating various localization problems The numerical results show that the developedmodel can simulate the observed unstable behaviors such as stress drop and deviation of local strain fromglobal strain during nucleation and propagation of martensitic phase Furthermore various materialinstabilities of SMAs such as softening and divergence of local global strain are simulated using theproposed non local model Rate dependency and temperature variations are also taken into account byextending the model to include the thermo mechanical coupling of the material with its environment Finally based on the multiplicative decomposition of the deformation gradient into elastic and inelasticparts the proposed small strain model is extended to finite deformations Keywords Shape memory alloys Non local model Unstable behavior Thermo mechanicalcoupling Finite element 1 IntroductionShape memory alloys SMAs are a group of smart materials which can recover theirshape even after severe deformations Hence they are extensively used in various areassuch as medical appliances automotive engineering robotics and aerospace Themechanism of the shape recovery ability is based on the phase transformation betweenmartensite and austenite phases Due to their unique biocompatibility andsuperelasticity NiTi based SMAs are the most frequently used materials 1
استاد راهنما :
محمود كدخدايي، محمد مشايخي
استاد مشاور :
بيژن برومند
استاد داور :
غلامحسين لياقت، جمال ارغواني، حميد هاشم الحسيني، عباس قايي
