ISDMM 2007 Defect and Material Mechanics Proceedings of the International Symposium on Defect and Material Mechanics (ISDMM), held in Aussois, France, March 25–29, 2007 Edited by CRISTIAN DASCALU University J. Fourier, Grenoble, France GE´ RARD A. MAUGIN University Pierre etMarieCurie, Paris,France and CLAUDE STOLZ EcolePolytechnique, Palaiseau, France Reprinted from International Journal of Fracture Volume 147, Nos. 1–4 (2007) PublishedbySpringer, P.O. Box17, 3300AADordrecht, The Netherlands Soldand distributed in North, CentralandSouth America BySpringer, 101PhilipDrive, Norwell, MA02061, USA Inallother countries, soldanddistributed BySpringer P.O. Box322, 3300AH Dordrecht,The Netherlands Libraryof Congress Control Number:2008924449 ISBN-13: 978-1-4020-6928-4 e-ISBN-13: 978-1-4020-6929-1 Printed onacid-freepaper (cid:1)2008Springer AllRights Reserved. Nopart of thematerial protectedbythis copyrightnotice maybereproducedor utilized in anyform orbyanymeans, electronic ormechanical, includingphotocopying, recording orbyany information storage andretrieval system,without written permissionfrom the copyrightowner. Springer.com Table of Contents Preface 1 C. Dascalu and G.A. Maugin Reciprocity in fracture and defect mechanics 3–11 R. Kienzler Configurational forces and gauge conditions in electromagnetic bodies 13–19 C. Trimarco The anti-symmetry principle for quasi-static crack propagation in Mode III 21–33 G.E. Oleaga Configurational balance and entropy sinks 35–43 M. Epstein Application of invariant integrals to the problems of defect identification 45–54 R.V. Goldstein, E.I. Shifrin and P.S. Shushpannikov On application of classical Eshelby approach to calculating effective elastic moduli of 55–66 dispersed composites K.B. Ustinov and R.V. Goldstein Material forces in finite elasto-plasticity with continuously distributed dislocations 67–81 S. Cleja-T¸igoiu Distributed dislocation approach for cracks in couple-stress elasticity: shear modes 83–102 P.A. Gourgiotis and H.G. Georgiadis Bifurcation of equilibrium solutions and defects nucleation 103–107 C. Stolz Theoretical and numerical aspects of the material and spatial settings in nonlinear 109–116 electro-elastostatics D.K. Vu and P. Steinmann Energy-based r-adaptivity: a solution strategy and applications to fracture mechanics 117–132 M. Scherer, R. Denzer and P. Steinmann Variational design sensitivity analysis in the context of structural optimization and 133–155 configurational mechanics D. Materna and F.-J. Barthold An anisotropic elastic formulation for configurational forces in stress space 157–161 A. Gupta and X. Markenscoff Conservation laws, duality and symmetry loss in solid mechanics 163–172 H.D. Bui Phase field simulation of domain structures in ferroelectric materials within the context of 173–180 inhomogeneity evolution R. Müller, D. Gross, D. Schrade and B.X. Xu An adaptive singular finite element in nonlinear fracture mechanics 181–190 R. Denzer, M. Scherer and P. Steinmann Moving singularities in thermoelastic solids 191–198 A. Berezovski and G.A. Maugin Dislocation tri-material solution in the analysis of bridged crack in anisotropic bimaterial 199–217 half-space T. Profant, O. Ševe9cek, M. Kotoul and T. Vysloužil Study of the simple extension tear test sample for rubber with Configurational Mechanics 219–225 E. Verron Stress-driven diffusion in a deforming and evolving elastic circular tube of single 227–234 component solid with vacancies C.H. Wu Mode II intersonic crack propagation in poroelastic media 235–267 E. Radi and B. Loret Material forces for crack analysis of functionally graded materials in adaptively refined 269–283 FE-meshes R. Mahnken A multiscale approach to damage configurational forces 285–294 C. Dascalu and G. Bilbie Preface C.Dascalu · G.A.Maugin The volume presents recent developments in the This special issue aims at bringing together recent theoryofdefectsandthemechanicsofmaterialforces. developmentsinMaterialMechanicsandthemoreclas- MostofthecontributionswerepresentedattheInter- sicalDefectMechanicsapproaches.Thecontributions national Symposium on Defect and Material Forces arehighlightingrecentresearchontopicslike:fracture (ISDMM2007), held in Aussois, France, March 25– and damage, electromagnetoelasticity, plasticity, dis- 29,2007. tributed dislocations, thermodynamics, poroelasticity, OriginatedintheworksofEshelby,theMaterialor generalized continua, structural optimization, conser- Configurational Mechanics experienced a remarkable vationlawsandsymmetries,multiscaleapproachesand revivaloverthelasttwodecades.Whenthemechanics numericalsolutionstrategies. ofcontinuaisfullyexpressedonthematerialmanifold, We expect the present volume to be a valuable it captures the material inhomogeneities. The driving resource for researchers in the field of Mechanics of (material)forcesoninhomogeneitiesappearnaturally DefectsinSolids. in this framework and are requesting for constitutive We dedicate this special issue to the memory of modelingoftheevolutionofinhomogeneitiesthrough the late Professor George Herrmann (1921–2007). kineticlaws. G. Herrmann was a prestigious scientist, well-known Inthisway,ageneralschemefordescribingstruc- in the international mechanics community. In the last tural changes in continua is obtained. The Eshelbian years,hewasanactiveresearcherinthefieldofMate- mechanicsformulationcomesupwithaunifyingtreat- rialMechanics.GeorgeHerrmannsupportedtheorga- mentofdifferentphenomenalikefractureanddamage nizationandregisteredforattendingtheISDMM2007 evolution,phasetransitions,plasticityanddislocation Symposium in Aussois, before his sudden dead on motion,etc. January7,2007.Noneofuswillforgethispassionfor mechanicalsciences,hisenthusiasmandgenerosity. B C.Dascalu( ) LaboratoireSolsSolidesStructures,UniversitéJoseph Fourier,Grenoble,DomaineUniversitaire,B.P.53, 38041 Grenoblecedex9,France e-mail:[email protected] G.A.Maugin UniversitéPierreetMarieCurie,InstitutJeanLeRond d’Alembert,Case152,4placeJussieu, 75252Pariscedex05,France e-mail:[email protected] DefectandMaterialMechanics.C.Dascalu,G.A.Maugin&C.Stolz(eds.), 1 doi:10.1007/978-1-4020-6929-1_1,©SpringerScience+BusinessMediaB.V.2008 Reciprocity in fracture and defect mechanics R.Kienzler Abstract Fordefectsinsolids,whendisplacedwithin The dot marks the scalar product between the two thematerial,reciprocityrelationshavebeenestablished vectors. In double-indexed terms, the first index indi- recentlysimilartothetheoremsattributedtoBettiand cates the position at which the quantity is measured Maxwell. These theorems are applied to crack- and (effect),andthesecondindexindicatesthecausedue defect-interactionproblems. towhichthisquantityoccurs. ToreachascalarversionofBetti’stheoremthedis- Keywords Reciprocity·Fracture·Defect placementcomponentof u inthedirectionof F is 12 1 interaction·Materialforces introducedasuP andthecomponentofu inthedirec- 12 21 tion of F as uP (cf. Fig. 1). With the magnitude F 2 21 1 and F of F and F ,respectively,itis 2 1 2 1 Introduction F uP = F uP. (2) 1 12 2 21 Whentreatingproblemsoflinearelasticsystems,such SinceuP isproportionalto F anduP isproportional 12 2 21 asbeams,framesortwo-andthree-dimensionalcontin- to F influencecoefficientmaybedefinedas 1 uouselasticsolids,thereciprocitytheoremsassociated with the names of Betti and Maxwell have proven to u1P2 =δ12F2, (3a) bequitevaluable.Initssimplestform,Betti’stheorem uP =δ F , (3b) 21 21 1 statesthatifalinearelasticbodyissupportedproperly and according to Marguerre (1962), Maxwell’s theo- such that rigid body displacements are precluded and remstates ifanexternalforce F atpoint1whichproducesadis- 1 placement u21 at some other point 2, then a force F2 δ12 =δ21. (4) at2wouldproduceadisplacementu at1where(cf. 12 Thereciprocityrelationsarebasedontheresultthatthe e.g.,Marguerre1962) energystoredinanelasticbodyafterapplicationoftwo F1·u12 = F2·u21. (1) forcesisindependentoftheirsequenceofapplication, andequalstheexternalworkdoneonthebody.Various Thecontentsofthepresentpaperhasbeendevelopedtogether applicationsofthesetheoremsaretobefoundin,e.g., withProf.Dr.Dr.h.c.GeorgeHerrmann,StanfordUniversity, California,whopassedawayonJanuary7,2007. TimoshenkoandGoodier(1970),Barber(2002). Duringtherecentdecadesanewtopichasemerged B R.Kienzler( ) in mechanics of elastically deformable media which DepartmentofProductionEngineering, is variously described as Defect Mechanics, Fracture UniversityofBremen,Bremen,Germany e-mail:[email protected] Mechanics,ConfigurationalMechanics,Mechanicsin DefectandMaterialMechanics.C.Dascalu,G.A.Maugin&C.Stolz(eds.), 3 doi:10.1007/978-1-4020-6929-1_2,©SpringerScience+BusinessMediaB.V.2007 4 R.Kienzler qqq FFF 111 FFF FFF 1 222 uuu1111 uuu111PPP222 2222 BBB1111 BBB1P2 2222 2 111222 uuuPPP uuu 12 BBBP BBB 222111 222111 21 21 Fig.2 Stressedelasticbodycontainingtwopointdefects Fig.1 Elasticbodysubjectedtotwoforces Basedonthesimilarargument(asappliedinPhysi- calSpace)thatthechangeofenergystoredinthebody afterapplicationoftwomaterialdisplacementsisinde- Material Space or Eshelbian Mechanics (cf. Maugin pendentoftheirsequenceofapplication,andequalsthe 1993;Gurtin2000;KienzlerandHerrmann2000).The work done of the material forces in the material dis- importance of this topic is based on the necessity of placements, a material, Betti-like reciprocity theorem improvedmaterialmodelingofdefectsofvarioustypes isestablished(HerrmannandKienzler2007a)as andscalesindeformablesolids.Andthisnecessityin turn is the result of developing new technologies in a λ2· B21 =λ1· B12, (5) varietyofappliedfieldssuchasdevicesinIT,aerospace statingthattheworkinthematerialtranslationat2of andenergysectors. thechangeofthematerialforceduetoamaterialtrans- In approaching configurational mechanics one can lationat1equalstheworkinthematerialtranslationat saythatamaterialforceisassociatedwithadefectin 1ofthechangeofthematerialforceduetoamaterial astressedelasticbody,becauseifthisdefectweredis- translationat2. placedwithinthebody,thetotalenergyofthesystem NotethedifferencebetweenPhysicalandMaterial wouldbechangedandthenegativeratioofthischange Space: in Physical Space, the applied physical forces andthedisplacement,inthelimitasthedisplacement arethecausesof(thechangeof)physicaldisplacements ismadetoapproachzero,isthematerialforceonthe (effects) whereas in Material Space the material dis- defect. placementcause(changesof)materialforces(effects). Let us consider a linearly elastic body of arbitrary Inanalogy,ascalarversionofEq.5isreachedbyintro- geometryproperlysupportedandsubjectedtosurface ducingthecomponentof B inthedirectionofλ as 21 2 tractionsand/orbodyforces.Andletusassumethatthe BP,thecomponentofB inthedirectionofλ asBP 21 12 1 12 bodycontainsanarbitrarynumberandtypeofdistrib- (cf.Fig.2)andthemagnitudesofλ andλ asλ and 1 2 1 utedorlocalized(point)defects,suchasdislocations, λ ,respectively,andiffollows 2 cracks,inclusions,cavities,etc.Letusfocusattention on two localized defects placed at positions 1 and 2 λ2B2P1 =λ1B1P2. (6) and let the associated material forces be the vectors Since linearity is implied, material influence coeffi- B and B respectively. Now, defect 1 will be dis- 10 20 cientsmaybedefinedas placed by an amount λ relatively to the material in 1 BP =β λ , (7a) whichthedefectispositioned(materialdisplacement). 21 21 1 In turn the material force at 1 will be changed by an BP =β λ , (7b) amountB andthematerialforce2willbechangedby 12 12 2 11 B21.Thematerialdisplacementisassumedtobesmall and a material, Maxwell-like reciprocity theorem is inthesensethatlinearityisimpliedbetweenmaterial obtained(HerrmannandKienzler2007a) displacements and material forces, e.g., B ∝ λ . If 21 1 β =β . (8) defect2wouldbemateriallydisplacedbyλ themate- 21 12 2 rialforceat1and2wouldbechangedby B and B , It states that the change of the material force at 2 in 12 22 respectively. thedirectionofthematerialdisplacementλ duetoa 2 Reciprocityinfractureanddefectmechanics 5 Fig.3 Crackconfiguration bb withinabarintension aa aa 22 11 NN NN aa 11 aa 22 bb unit-materialtranslationat1equalsthechangeofthe (a) materialforceat1inthedirectionofλ duetoaunit- 1 materialtranslationat2. Theimplicationsofanon-linearformulationofthe reciprocityrelation(5)havebeendealtwithinKienzler andHerrmann(2007).Byconsideringastressedelastic bodysubjectedsequentiallytoamaterialdisplacement aa of a defect and the application of a physical force a novel type of coupling of Physical and Material Mechanicsbymeansofareciprocitytheoremhasbeen aa aa establishedinHerrmannandKienzler(2007b). It is the intention of the present contribution to (b) exploresomeapplicationsofthetwotheorems(5)and (8)infractureanddefectmechanics. 111 222 2 Interactingcracks aa aa 11 22 Interactingcrackshavebeentheobjectofresearchover severalyears(cf.,e.g.,Erdogan1962;Panasyuketal. aa bb aa 1977;Gross1982).Thematerialforcesatcracktipsare 11 22 usually calculated from the path-independent J inte- gral (Rice 1968). Reciprocity relations are, therefore, Fig.4 Singlecrack(a),twoneighbouredcracks(b) concernedwiththechangeofthe J integralduetothe translation of some other defect, e.g., the change of andloadedbyanaxialforceintensionasdepictedin lengthofacrack2intheneighbourhoodoftheorigi- Fig.3. nal crack 1. Usually, the solution of crack-interaction If a single crack is considered first, the key idea is problemsinvolveeithersomeadvancesanalyticaltools thattheenergy-releaserateisproportionaltothelength or an extended numerical investigation. Based on the oftheshadedstripinFig.4a,i.e., √ √ strength-of-materials theories, a simple first estimate G = J ∝2a 2; J =C2a 2. (9) forinteractingedgecracksinanelasticbarunderten- sionhavebeengivenrecentlybyRohdeandKienzler TheconstantC,say,wouldbeproportionaltothesquare (2005)andRohdeetal.(2005),andthereciprocityrela- of the applied load, inverse proportional to Young’s tionsareappliedwithinthissimplifiedproblemsetting. modulus,andwouldcombinesomeinformationabout InRohdeandKienzler(2005)andRohdeetal.(2005) thegeometryofthebar. bars are investigated with a set of 2×2 edge cracks Inthepresenceofasecondcrack,cf.Fig.4b,both symmetricallypositionedwithrespecttoitslengthaxis stripscannotdevelopcompletelyduetoshieldingsuch 6 R.Kienzler that the energy-release rate of crack 1 is proportional (a) tothelengthofthedarklyshadedareaontheleftand theenergyreleaserateofcrack2isproportionaltothe 11 lightlyshadedareaontheright,i.e., √ 1 G = J = B = 2C(3a −a +b), (10a) 1 1 10 1 2 2 111 222 √ 1 G = J = B = 2C(3a −a +b), (10b) 2 2 20 2 1 2 where a and a are the crack lengths of crack 1 and 1 2 (b) crack 2, respectively, and b is the distance of both cracks.Eq.10isvalidaslongas 22 |a −a |<b<a +a . (11) 1 2 1 2 It is observed, of course, that the crack configuration 111 222 represents a mixed-mode problem and the vector J doesnotpointinthedirectionofapotentialself-similar crack extension. It is sufficient, however, to consider Fig.5 Changeofenergy-releaseratesduetocrackextensionλ1 only the component of J in the direction of (cid:4)a1 or ofcrack1(a)andλ2ofcrack2(b) (cid:4)a ,correspondingto BP or BP.Detailsoftheanal- 2 12 21 ysisandthevalidationoftheresultsaregiveninRohde andKienzler(2005)andRohdeetal.(2005). reciprocity relations in Material Space. In words: the With the simple relations (10) at hand it is easy to changeofthe J integralatcrack1duetoachangeof check the reciprocity theorems. A crack extension of thecracklengthofcrack2equalsthechangeofthe J crack1,(cid:4)a ,correspondstoamaterialtranslationλ . integralatcrack2duetothechangeofthecracklength 1 1 Duetoλ ,thematerialforces B and B changeto ofcrack1.Thisrelationmayalsobeverifiedwithina 1 10 20 morerigorousapproacheitheranalyticallyornumeri- B11 = B1λ1 −B10 cally and may be used to establish influence surfaces √ 1 = 2C[3(a +λ )−a +b−3a +a −b] for defects within the stress state of a crack tip. This 1 1 2 1 2 2 problemwillbefurthertreatedinthenextsection. √ 3 =+ 2Cλ , (12a) 1 2 B21 = B2λ1 −B10 √ 1 = 2C[3a2−(a1+λ1)+b−3a2+a1−b] 3 Interactionofanedgedislocationwithacircular 2 √ hole 1 =− 2Cλ , 1 2 =β λ . (12b) Asafurtherexamplefortheapplicationofthematerial 21 1 reciprocityrelationsletusconsiderthefollowingdefect Ifcrack2isextendedbyanamountλ2thechangeofthe configuration.Withinaninfinitelyextendedplaneelas- materialforcesatcrack1and2iscalculatedsimilarly tic sheet an edge dislocation is situated in the origin as of a plane Cartesian coordinate system (x ,x ) with 1 2 √ B =−1 2Cλ =β λ , (12c) Burgersvectorpointing(withoutlossofgenerality)in 12 2 2 12 2 x -direction.Atx = ξ (i = 1,2)acircularholewith √ 2 i i B =+3 2Cλ . (12d) radiusr0iscentred,or,inpolarcoordinates,atdistance 22 2 2 d > r (ε = d/r > 1) under the angle ϕ measured 0 0 The changes of the various energy-release rates have fromthex -axisasdepictedinFig.6. 1 beenmadegraphicinFig.5 Duetoamaterialtranslationξ →ξ +λ thetotal i i i Substitution of (12b) and (12c) into relations (5) energy(cid:8)ofthesystemchangesandtheenergy-release or (6) and (8) confirms and illustrates the validity of rateisdefinedas