6099

5708

كارشناسي ارشد

مكانيك

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1390

چهارده،131ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

محمد مشايخي

سعيد ضيايي راد

3/5/90

حميد هاشم الحسيني، محمود كدخدايي

مهندسي مكانيك

ID5708

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Continuum Damage Mechanics Analysis using Extended Finite Element Method Reza Pourmodheji r pourmodheji@me iut ac ir May 1 2011 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Mashayekhi Mohammad Assistant Professor Email mashayekhi@cc iut ac irAbstractFinite element method FEM one of the most practical numerical methods in mechanical engineering problems has some limitations to model crack growth within the fracture mechanic analysis In spite of all achievements thecontinuum basis of FEM has remained as a source of relative disadvantage for discontinuous fracture mechanics High dependency of crack to finite element mesh re meshing requirement and need to singular element in particularcases are some defects of FEM in modeling crack growth In recent years the Extended Finite Element Method XFEM based on mesh based partition of unity method has emerged as an efficient numerical method to modeldiscontinuities specially crack as a strong discontinuity in fracture mechanic analysis In the XFEM extrinsicenrichment of displacement field is applied to extend the standard displacement based approximation space whichleads to improve the accuracy of discontinuous problems The idea is to embedding discontinuous functions in FEapproximation through the partition of unity concept Therefore the crack path is independent of finite elementmesh and as a result no re meshing or utilizing singular elements is needed It is now well known that the applicability of the J based single parameter fracture mechanics is restricted to highconstraint crack geometries and materials of low ductility For highly ductile materials the fracture process zone islarge and the crack tip fields are no longer adequately characterized by the J integral alone Micro mechanicallybased damage models which simulate the physical process of void nucleation growth and coalescence usingcontinuum mechanics equations are among the most promising methods to investigate fracture behavior in ductilematerials The advantage of a micromechanical damage model compared with conventional fracture mechanics isthat in general the model parameters are only material dependent and not geometry dependent The damage modelallows damage assessments at every point of a structure for any geometry or loading as long as the damage

محمد مشايخي

سعيد ضيايي راد

حميد هاشم الحسيني، محمود كدخدايي