z n . i r c . n o i c s @ s u q a b A z n . i r c . n o i c s @ s u q a h b c A r a z e n s . i e r c R . n n o o i c i c s S @ y s b u e q s a u b A l a z n n o . s i r r c e . p n o r o i c F s Modeling Fracture and Failure with Abaqus @ . h c s r u a q e a s b e sem R A © | mtluaèstssayDS ion ri.nz oc.sd3.ww Sc n.c w y o b i c e s s @ u s al u n q o a s b r A R 6.12 e p z n r o i. r F c About this Course . . n h o c i Course objectives r c a Upon completion of this course you will be able to: s e @ Use proper modeling techniques for capturing crack-tip singularities in fracture mechanics problems s Use Abaqus/CAE to create meshes appropriate for fracture studies e s Calculate stress intensity factors and contour integrals around a crack tip R u Simulate material damage and failure q n Simulate crack growth using cohesive behavior, VCCT, and XFEM a o ©stelumaèstssayDS TarS giemtueladt ea luowd-iceynclce efa tigue crack growth y Sci nz Ab | m Simulation Analysts b . oc.sd3.www Prerequisites se .cri This course is recommended for engineers with experience using Abaqus n u o l i a c n s o @ s s r e u p q 3 days a r o b F A 1 z n . i r c . n o i c s @ s u q a b A z n . i r c . n o i c s @ s u q a h b c A r a z e n s . i e r c R . n n o o i c i c s S @ y s b u e q s a u b A l a z n n o . s i r r c e . p n Day 1 o r o i c Lecture 1 Basic Concepts of Fracture Mechanics F s @ . h Lecture 2 Modeling Cracks c s r u Lecture 3 Fracture Analysis a q e a Workshop 1 Crack in a Three-point Bend Specimen s b e sem R A © | mtluaèstssayDS Workshop 2 Crack in a Helicopter Airframe Component ion ri.nz oc.sd3.ww Sc n.c w y o b i c e s s @ u s al u n q o a s b r A e p z n r o i. r F c Day 2 . . n h o c i Lecture 4 Material Failure and Wear r c a s e @ Lecture 5 Element-based Cohesive Behavior s e s Workshop 3 Crack Growth in a Three-point Bend Specimen using Cohesive Connections (Part 1) R u q n Workshop 4 Crack Growth in a Helicopter Airframe Component using Cohesive Elements a o ©stelumaèstssayDS Lectur We 6o rkshop 3 SCurarfcakc Ge-rboawstehd i nC ao hTehsrievee- pBoeihnat vBioern d Specimen using Cohesive Connections (Part 2) y Sci nz Ab | m b . oc.sd3.w e cri ww s . n u o l i a c n s o @ s s r e u p q a r o b F A 2 z n . i r c . n o i c s @ s u q a b A z n . i r c . n o i c s @ s u q a h b c A r a z e n s . i e r c R . n n o o i c i c s S @ y s b u e q s a u b A l a z n n o . s i r r c e . p n Day 3 o r o i c Lecture 7 Virtual Crack Closure Technology (VCCT) F s @ . h Workshop 5 Crack Growth in a Three-point Bend Specimen using VCCT c s r u Lecture 8 Low-cycle Fatigue a q e a Lecture 9 Mesh-independent Fracture Modeling (XFEM) s b e sem R A © | mtluaèstssayDS W Woorrkksshhoopp 67 CMroadcekl iGngro Cwrtahc ikn Par oTpharegea-tpioonin itn B ae Pndre Ssspuerceim Veens suesl inwgit hX AFEbaMq us using XFEM ion ri.nz oc.sd3.ww Sc n.c w y o b i c e s s @ u s al u n q o a s b r A e p z n r o i. r F c Legal Notices . . n h o c i The Abaqus Software described in this documentation is available only under license from Dassault r c a Systèmes and its subsidiary and may be used or reproduced only in accordance with the terms of such s e @ license. s This documentation and the software described in this documentation are subject to change without e s prior notice. R u Dassault Systèmes and its subsidiaries shall not be responsible for the consequences of any errors or q n omissions that may appear in this documentation. a o ©stelumaèstssayDS Np©Pero iDrn mpateaissdrsts aiionouf n lttth hoSeifsy U Dsdtnaoèisctmesudaem usSe,lt tn2 aSt0taye1tssi2ot è.on mf mAeamsy eo brri ecit asr e spurbosdiudciaerdy. o r distributed in any form without prior written y Sci nz Ab | moc.sd3.w ASbysatqèumse, sth oer 3itDs Ss ulobgsoid,i aSrIiMesU iLnI Ath aen UdS C aAnTdIA/o ar roeth treard ceomunatrrkiess o. r registered trademarks of Dassault e b cri. ww Other company, product, and service names may be trademarks or service marks of their respective s . n owners. For additional information concerning trademarks, copyrights, and licenses, see the Legal u o Notices in the Abaqus 6.12 Release Notes and the notices at: l i http://www.3ds.com/products/simulia/portfolio/product-os-commercial-programs. a c n s o @ s s r e u p q a r o b F A 3 z n . i r c . n o i c s @ s u q a b A z n . i r c . n o i c s @ s u q a h b c A r a z e n s . i e r c R . n n o o i c i c s S @ y s b u e q s a u b A l a z n n o . s i r r c e . p n Revision Status o r o i c F s @ . h Lecture 1 5/12 Updated for 6.12 c s Lecture 2 5/12 Updated for 6.12 r u Lecture 3 5/12 Updated for 6.12 a q Lecture 4 5/12 Updated for 6.12 e a s b Lecture 5 5/12 Updated for 6.12 e sem Lecture 6 5/12 Updated for 6.12 R A © | mtluaèstssayDS LLLeeeccctttuuurrreee 789 555///111222 UUUpppdddaaattteeeddd fffooorrr 666...111222 ion ri.nz oc.sd3.ww WWoorrkksshhoopp 12 55//1122 UUppddaatteedd ffoorr 66..1122 Sc n.c w Workshop 3 5/12 Updated for 6.12 y o Workshop 4 5/12 Updated for 6.12 b i c Workshop 5 5/12 Updated for 6.12 e s Workshop 6 5/12 Updated for 6.12 s @ Workshop 7 5/12 Updated for 6.12 u s al u n q o a s b r A e p z n r o i. r F c . . n h o c i r c a s e @ s e s R u q n a o b i c A S z y n b . i r e c s . n u o l i a c n s o @ s s r e u p q a r o b F A 4 z n . i r c . n o i c s @ s u q a b A z n . i r c . n o i c s @ s u q a h b c A r a z e n s . i e r c R . n n o o i c i c s S @ y s b u e q s a u b A l a z n n o . s i r r c e . p n o r o i Notes c F s @ . h c s r u a q e a s b e A R z n n o . i i r c c S . n y o b i c e s s @ u s al u n q o a s b r A e p z n r o i. r F c . . n h o c i r c a s e @ s e s R u q n a o b i c A S z y n b . i r e c s . n u o l i a c n s o @ s s r e u p q a r o b F A 5 z n . i r c . n o i c s @ s u q a b A z n . i r c . n o i c s @ s u q a h b c A r a z e n s . i e r c R . n n o o i c i c s S @ y s b u e q s a u b A l a z n n o . s i r r c e . p n o r o i Notes c F s @ . h c s r u a q e a s b e A R z n n o . i i r c c S . n y o b i c e s s @ u s al u n q o a s b r A e p z n r o i. r F c . . n h o c i r c a s e @ s e s R u q n a o b i c A S z y n b . i r e c s . n u o l i a c n s o @ s s r e u p q a r o b F A 6 z n . i r c . n o i c s @ s u q a b A z n . i r c . n o i c s @ s u q a h b c A r a z e n s . i e r c R . n n o o i c i c s S @ y s b u e q s a u b A l a z n n o . s i r r c e L1.1 . Lesson 1: Basic Concepts of Fracture Mechanics p n o r o i c Lesson content: F s @ . h Overview c s Introduction r u a q Fracture Mechanisms e a Linear Elastic Fracture Mechanics s b Small Scale Yielding e © | mstelumaèstssayDS ETNMhnoixeene rlJidgn--yieMn aCtoero dgFnerrsaa Fildc rteaurcraettu ioMrene sc hanics ion R ri.nz A oc.sd3.ww Interfacial Fracture Sc n.c w Creep Fracture y o Fatigue b i c e s s @ u s al u n q o a 90 minutes s b r A e p z n r o i. r L1.2 F c Overview . . n h o c i This lecture is optional. r c a s e @ It aims to introduce the necessary fracture mechanics concepts and quantities that are relevant to the Abaqus s functionality that is presented in the subsequent lectures. e s R u If you are already familiar with these concepts, this lecture may be omitted. q n a o ©stelumaèstssayDS y Sci nz Ab | m b . oc.sd3.w e cri ww s . n u o l i a c n s o @ s s r e u p q a r o b F A 7 z n . i r c . n o i c s @ s u q a b A z n . i r c . n o i c s @ s u q a h b c A r a z e n s . i e r c R . n n o o i c i c s S @ y s b u e q s a u b A l a z n n o . s i r r c e L1.3 . p n Introduction o r o i c Fracture mechanics is the field of solid mechanics that deals with the behavior of cracked bodies subjected to F s stresses and strains. @ . h These can arise from primary applied loads or secondary self-equilibrating stress fields (e.g., residual c s stresses). r u a q e a s b e © | mstelumaèstssayDS ion R ri.nz A oc.sd3.ww Sc n.c w y o b i c e s s @ u The objective of fracture mechanics is to characterize the local deformation around a crack tip in terms s of the asymptotic field around the crack tip scaled by parameters that are a function of the loading and al u global geometry. n q o a s b r A e p z n r o i. r L1.4 F c Fracture Mechanisms (1/4) . . n h o c i For engineering materials, such as metals, r c a there are two primary modes of fracture: brittle s and ductile. e @ s e s Brittle fracture R u q Cracks spread very rapidly with little or n a no plastic deformation. o ©stelumaèstssayDS Ctsceirrzanaedcc k pkt orsgo rctvohoiwdanettt hidinn. uittheiae tt eolo iganrd oainw bg ra iwtntildlel icmnacauretseaers iael in y Sci nz Ab | m b . oc.sd3.w Ductile fracture e cri ww s . n Three stages: void nucleation, growth, u o and coalescence. l i The crack moves slowly and is a c accompanied by a large amount of n s plastic deformation. o @ The crack typically will not grow unless s the applied load is increased. r s e u p q a r o b F A 8 z n . i r c . n o i c s @ s u q a b A z n . i r c . n o i c s @ s u q a h b c A r a z e n s . i e r c R . n n o o i c i c s S @ y s b u e q s a u b A l a z n n o . s i r r c e L1.5 . p n Fracture Mechanisms (2/4) o r o i c Brittle fracture in polycrystalline materials displays either cleavage (transgranular) or intergranular F s fracture. @ . h This depends upon whether the grain boundaries are stronger or weaker than the grains . c s r u a q e a s b e sem R A © | mtluaèstssayDS ion ri.nz oc.sd3.ww Sc n.c w y o b i c Cleavage fracture e s s @ u s al u n q o a s b r A e p z n r o i. r L1.6 F c Fracture Mechanisms (3/4) . . n h o c i Ductile fracture has a dimpled, cup-and-cone fracture appearance . r c a s e @ Ductile fracture surfaces have larger necking regions and an overall rougher appearance than a s brittle fracture surface. e s R u q n a o ©stelumaèstssayDS y Sci nz Ab | m b . oc.sd3.w e cri ww s . n u o l i a c n s o @ s s r e u p q a r o b F A 9 z n . i r c . n o i c s @ s u q a b A z n . i r c . n o i c s @ s u q a h b c A r a z e n s . i e r c R . n n o o i c i c s S @ y s b u e q s a u b A l a z n n o . s i r r c e L1.7 . p n Fracture Mechanisms (4/4) o r o i c Fracture process zone F s @ . h The fracture process zone is the region around the crack tip where dislocation motions, material damage, etc. occur. c s r u a q It is a region of nonlinear deformation. e a s b sem The fracture process zone size is characterized by Re A © | mtluaèstssayDS ae itnhuemr binecrl uosfi ognra oinr ssiezceosn fdo rp bhraitstlee pfraarctitculere s opra cings for ductile fracture. ion ri.nz oc.sd3.ww Dcaifpfearbeinlitti ethse ories have been advanced to describe the fracture process in order to develop predictive Sc n.c w y o LEFM b i c Cohesive zone models e s EPFM s @ Etc. u s al u n q o a s b r A e p z n r o i. r L1.8 F c Linear Elastic Fracture Mechanics (1/10) . . n h o c i Fracture modes r c a s e @ Linear Elastic Fracture Mechanics (LEFM) s considers three distinct fracture modes: Modes e s I, II, and III R u q These encompass all possible ways a crack tip n a can deform. o ©stelumaèstssayDS Mode I : y Sci nz Ab | m The forces are perpendicular to the b . oc.sd3.w crack, pulling the crack open. e cri ww This is referred to as the opening mode. s . n u o l i a c n s o @ s s r e u p q a r o b F A 10