Microsoft Word - numero 14 articolo 1 T in M Sch Dep mja M Sch Es AB bu En ho het for the cir cre wh ass me KE fra IN bod ass hom situ An exa the def pla H he inter n materi . N. James hool of Marine epartment of M ames@plymou . Newby hool of Marine skom Research BSTRACT. Th t which is a ngineering c mogeneous terogeneous rm of a genu e differing cumstances eep, environ here welding sociated with etallurgical fa EYWORDS. C acture; enviro NTRODUCTIO istoric analys of unc dies) have be sessments fo mogeneous, uations arise. nalytical comp ample, the in e presence o formation) an asticity and f H rface be ial perfo s e Science & E Mechanical Eng uth.ac.uk e Science & E h and Innovati his paper co a determinin components and gener s and often n uine interfac philosophie where envir nmentally-ass g is used to j h cracking a actors in me Continuum onment. ON cally, the educ sing the beha cracked bodie een very powe r engineering isotropic co plexity is also crease in rigo of a crack. nd hydrostat fracture are f etween m ormance Engineering, U ngineering, Nel Engineering, U ion Centre, Ro nsiders an im ng factor in m and struct rally continu non-continu ce between m es of desig ronmental in sisted cracki oin compon and uses case echanical per mechanics; cation of mec aviour of stru es subject to e erful in advan g artefacts. ontinuum, an o introduced a our necessitat Three dime tic (which re fundamentall M. N. James e metallu e University of Ply lson Mandela University of Ply osherville, Joha mportant top many aspect tures must, uum aspects uum reality o material and gn have to nfluences ha ing, or corro nents, or wh e study exam rformance o non-continu chanical engin uctures and m external load ncing our abil The key a nd considerab as the applied ted by a mov ensional stres esist plastic d ly controlled et alii, Frattura e urgy and lymouth, Plym Metropolitan lymouth, Plym annesburg, Sou pic, and one ts of the ser of necessi s of applied of material s d environme be merged ave a key ro osion), where here tribology mples drawn of materials. uum materia neers has had materials. In p or deformati lity to calcula assumptions ble complexi d loading or d ve from unidi ss states can deformation by inhomog ed Integrità Strut d mecha mouth (UK) University, P mouth (UK) uth Africa e that is ofte rvice perform ity, provide d load and structure an ent, e.g. at a d. The in ole in determ e performan y plays a rol n from engin als; metallur d a strong fo particular, so ion fields) an ate internal st in solid me ity is introd deformation irectional loa n be resolved and promote geneous, non tturale, 14 (2010 anics Port Elizabeth n poorly und mance of m a bridge b d displaceme d behaviour surface, or nterface has mining perfo nce is domin le. The pape neering prac rgical param cus on contin olid mechanic d fracture me resses and str echanics are uced into an field become ading to triaxi d into devia e fracture) s n-isotropic a 0) 5-16; DOI: 10 (South Africa derstood or metals (and o between the ent, and th r. This brid can be a vir particular ormance cha nated by fati er focuses o ctice to illust meters; case nuum mechan cs (dealing wi echanics (deal rains and to m usually that nalysis when es more realis ial constraint atoric (which tress compo and non-cont 0.3221/IGF-ESIS. a) misinterpre other materi e macrosco he microsco dge can take rtual one wh importance aracteristics ( igue or fract on the proble trate the role studies; fatig nics as a tool ith the behav ling with crac make realistic t the body n more com stic; consider, t which occur h promote sh nents. As b tinuum mate 14.01 5 eted, als). opic, opic, the here e in (e.g. ture, ems e of gue; l for viour cked c life is a plex , for rs in hear both erials http://www.gruppofrattura.it http://dx.medra.org/10.3221/IGF-ESIS.14.01&auth=true mailto: mjames@plymouth.ac.uk M.N 6 beh Sev pro stre pro An pla sim sca dis me the Th pre Ass gui of Th the def sur of ser Th tem me am cre to onc pos CR fati mo the It con dur frac cra pro of Th in t wa elem K’ spe T N. James et alii, haviour it mi veral factors ocess in which ess concentra omote 3D str nother import asticity is very mplified. Whe ale yielding, m tribution and echanics, dislo e concepts of he fundament edicting fract sessment of idance for en a component hus, in consid e fact that the fect populatio rface conditio the applied rvice cracking his paper will mperature. A echanical engi mbient temper eep mechanism be properly s ce a critical c sition that is d RACK TIP STR he first crack gr in many igue crack gr ore accurate K e elastic mode was noted b nsiderations, ring crack gro cture (with a acking of stru ovides the beg the 20th centu hese stress and the 1950’s on s governed b ment from th with fracture ecimen. The T Frattura ed Inte ight be antic serve to mitig h Poisson’s r ation factors ress states and tant factor is y extensive th ere plasticity metallurgical d size; heat tr ocation mech f uncertainty, tal role of pla ture using a the Integrity ngineering crit t or structure dering the beh eir macroscop on), the envir on (roughness field (e.g. pr g in materials l focus on th Although no ineering prac ratures is ofte ms is time-de scheduled. S crack size is difficult to in RESS FIELD issue worth rowth by the y circumstanc rowth. An in K-solutions o el for crack tip by Griffith [4 and that frac owth. This a a magnitude e uctures becau ginning of a s ury was the an d energy stran n crack tip str by the first te he crack tip. e occurring a e stress inten egrità Strutturale cipated that p gate these pe ratio is 0.5 an that arises fr d increase pla the relative s he design crite is limited frac factors (e.g. reatment and hanics and pl statistics and asticity in crac Failure Ana of Structures tical assessme to fracture an haviour of m pic behaviour ronment in w s, chemical c roportional o is truly a cutt he metallurgi n-metallic m ctice is concer en experience ependent and Sub-critical cr reached (whi nspect) fast fra S IN THE PR briefing con presence of a ces but under ncreasing em or improved f p stresses can 4] in a classi cture occurred approach expl equal to the v use of the co sound unders nalysis of crac nds were bro ress fields [7] rm in a serie This led to d at a critical m sity factor is e, 14 (2010) 5-1 prediction of erturbations; o d this tends t from plastic f astic constrain size of critica erion is likely cture will dom crystal struc hardness; su lasticity theor reliability hav cking of met alysis Diagra s containing ent of defects nd to plastic aterials under r reflects their which they op omposition, or non-propo ting edge inte cal-mechanic materials are b rned with the ed as a sudden d the damage racks may gro ich may be e acture occurs RESENCE OF nsidering con a plastic encla rpin the cont mphasis on m fatigue life pr n be improved ic paper that d when the e licitly links cr value of the c omplexity in standing of th ck tip stress f ought togethe . He recogni es expansion, defining the n material cons used in situa 16; DOI: 10.3221/ f structural b one is the fac to promote 2 flow. Howev nt (the move f al defects at f to be plastic minate and m cture; slip be urface conditi ry. Many ana ve to be facto tallic alloys ha am (FAD), w Defects [1], s [e.g. 2]. Th collapse and r applied load r microscopic erate (temper residual stres ortional multi rface between cs interface in both interest e behaviour o n and unfore can often be ow very slow either relative s in metals at F PLASTICIT cerns the pe ave surround tinuing contr multi-paramete rediction mod d to include i t the phenom nergy release rack size, app critical strain quantifying he driving for fields perform er to lay the f ised that the i through a 1/ numerator in stant value K ations where /IGF-ESIS.14.01 behaviour wo ct that plastic D stress state ver, increase from plane st fracture comp collapse of th material behav ehaviour; grai ion; residual alytical and n ored into the as led to the which was d and has been he FAD appro plots this stat d or deforma c composition rature, chemi ss state) as we iaxial loading n metallurgy, n relation to ting and imp of metals. It eseen phenom e monitored wly via fatigue ely small in te speeds which TY rturbations im ding the crack roversy surro er characteris dels, brings in influences ari menon of ru ed by crack ex plied stress an energy relea and measurin rce for crackin med by Inglis foundations o intensity of th /√r dependen this first stre KC appropriat the overall ould generall c deformation es, whilst a se in compone tress to plane pared with zo he structure a viour will refle in and phase stress state). numerical app analysis. adoption of developed for n adopted in oach conjoint te on a failure ation, full con n and conditi ical species, c ell as the mo g). The pred materials scie cracking pr portant, it re is also the c menon, whilst in service allo e or environm erms of the s h can reach ar mposed on t k. These pert unding plasti sation of cra nto sharper f sing from pla upture in sol xtension was nd the concep ase rate GC), b ng the work ng. Other im [5] and West of fracture me he applied str ncy where r i ess term (σ√a) te to the par stress-strain ly be difficul n is largely a econd is the l ent or structu strain situati ones of local and the analy ect interaction e dimensions This is the r proaches are a two param r the CEGB similar Britis tly considers e locus diagra nsideration ha ion (heat trea contact with o de, frequency diction and u ence and mec oblems in m emains true t ase that failu t failure by co owing repair mentally-assis scale of the s round Mach 0 the elastic str turbations are icity-induced ck tip stresse focus the que asticity. lids was gov equal to the pt of a materi but was diffic to fracture. mportant work tergaard [6]. echanics in th ress field nea is the distanc ) to be the ‘st rticular state constitutive b lt and imprec constant volu local reductio ural size tend ons). plasticity. W ysis can be gre ns between sm s; inclusion t realm of frac approximate meter approach B R6 docum sh and Europ the susceptib am. as to be given atment, hardn other parts), t y and comple understanding chanics. metals at amb that the bulk ure by crackin orrosion, wea and replacem ted cracking, structure, or 0.4 [3]. ress field driv e relatively m shielding du es, to give ei estion of whe verned by en energy absor ial’s resistanc cult to extend Nonetheles k in the early he work by Ir ar the tip of c ce of the stre tress intensity fa of stress in behaviour of cise. ume on in ds to When eatly mall type, cture and h to ment, pean bility n to ness, their exity g of bient k of ng at ar or ment but in a ving minor uring ither ether ergy rbed ce to d to ss, it part rwin rack ssed factor, the f the http://www.gruppofrattura.it http://dx.medra.org/10.3221/IGF-ESIS.14.01&auth=true cra stre as pla Lin in c eve (via lev the gov of are inte Ex abl Sat wit wo pla pla con stre driv cra dif T-s Th the wh pla wh wh cra inte pla com Co fun Dis acked body is ess concentra recognised in ane strain this near elastic fr cracked and s ents from the a the Irwin pl vels should be e K concept verned by the the applied st ea of fatigue ensity approa xtremely inter le to provide tisfactory ans th plasticity-in ork on this is astic ‘inclusion asticity-induce nstant volum esses must ex ving crack gr ack tip, and a fference in pri stress) or four he stress varia e Williams sol Nf h  here the two u ane. The 4-te Nf h  here the four u Nf h  here the four u ack growth K ensity acting astic interface mparable with onsidering dis nction is given 2 u  splacement fi linear and ela ation at the cr n the case of s relationship racture mecha stressed struc e bulk applied lastic zone co e a relatively to fatigue c e stress inten tress intensity crack growth aches. resting (and la e an adequat wers to these nduced shield ssue [12-14] c n’ representin ed closure) a me process wi xist at the in rowth forwar a shear-induce incipal stresse r-term solutio ant of the equ lution. The W 2y x   unknown coe rm solution i 2y x   unknowns are 2y x   unknowns ar KF, T-stress, a to retard crac (leading to a h photoelastic splacement fi n by:  iv z  ields can be s astic, i.e. whe rack tip). Cri f plane stress becomes G = anics and the ctures with an d elastic field. orrection to a low fraction crack growth nsity factor, th y, ΔK = Kmax h and life pre argely ignored te characteris e questions w ding of the cr considers the ng the plastic and compatib th Poisson’s nterface. The rds KF, a reta ed stress inte es [14], using ons to the We uation represe Williams solut 1 2 xyi Az   efficients are is: xyi A z     e A, B, C and 1 2 xyi Az   re A, B, C and a crack flank ck growth KR a KS term). T c data. ields, both p   'z z z  ubstituted int M. N. James e ere there is a l itical values o by the equat = K2/(1 – ν2)E stress intens n associated d Plasticity is apparent crack (perhaps < 0 rate on the hen sub-critic – Kmin. With ediction und d) questions sation of phe would seem li rack tip durin e boundary c c enclave surr bility-induced ratio ν = 0.5 e CJP model arding stress ensity KS. An g full-field pho estergaard or enting the CJ tion for 2-term 3 2Bz z C    A (A+B = 0 1 3 2 2z z z       d D, while the 1 3 2 2Bz z    d D and D+E contact stre R) and a comp This provides perpendicular  ' z to Eq. 4 to gi et alii, Frattura e limited extent of stress inten tion G = K2/ E. sity approach decoupling of primarily con k length), stre 0.6) of the yie basis that if cal crack grow the developm er cyclic load remain as to enomena tha ikely to assist g fatigue crac conditions tha rounding the d stresses at 5, whilst in el l [12, 14] for intensity KR nalysis of its otoelastic dat Williams [15] P model is gi ms, K and T- 0Cz 0) and C and 1 1 2 2(B z z    e CJP model i 1 0 2Cz Dz l   E = 0. This m ess with a 1/ patibility-indu fringe pattern and parallel ive: ed Integrità Strut t of crack tip nsity factor an /E where E have proven f local crack t nsidered throu ess state and eld strength o f critical crac wth under cyc ment of fractu ding has beco why, and ho at explicitly a t in resolving ck growth [10 at would be crack. Thes the elastic-pl lastic deform r crack tip str which captu capability in ta, indicate a l ] equations. iven below al stress is: z is the coo 1 02 )z Cz D  is given as: 3 2lnz Ez zln   model allows √r distributio uced shear str ns for differe to the crack tturale, 14 (2010 plasticity (wh nd strain ener is the elastic n very useful i tip microstru ugh its influe through the s of the alloy. ck growth un clic loading m ure mechanic ome the prim ow, an elastic arise from pl g a number o 0, 11]. The ex imposed on e arise from lastic interfac mation ν ≈ 0.3 resses leads t ures wake con characterisin lower fitting long with 2-t rdinate of a s ( )D z z nz for calculatio on behind th ress as a boun ence in princi k face, the M 0) 5-16; DOI: 10 hich arises fro rgy release ra modulus of in characteris cture and pla nces on speci stipulation th Paris [8] ext nder monoto may be gover cs into a matu me applicatio c approach to lastic deform of controversi xplanation ad the applied crack wake c ce. Plastic d 3 and plastici to a modified ntact influenc ng near-tip fri error than eit erm and 4-te stressed poin on of a stress he crack tip ( ndary conditi ipal stresses w Muskhelishvil 0.3221/IGF-ESIS. om the high l te are equival the material. sing critical st asticity contro imen complia hat nominal st ended the us onic loading ned by the ra ure discipline, on area for st o crack growt mation proces ies [9] associ dvanced in re elastic field b contact (so-ca deformation ity-induced sh d stress inten ces ahead of ringe patterns ther two- (K erm equations (1) nt in the com (2) (3) s intensity driv (leading to st ion at the ela which are dire li complex st (4) 14.01 7 local lent, . In tates olled ance tress se of was ange , the tress th is sses. ated cent by a alled is a hear nsity f the s for plus s for plex ving tress stic- ectly tress http://www.gruppofrattura.it http://dx.medra.org/10.3221/IGF-ESIS.14.01&auth=true M.N 8 wh   u,v  z A, Cas exa KS, fou It i pla N. James et alii, 2 u  z    Az  here:    ,z z B, C, D, E, F sting the CJP ample, using , KR and the T und as compo Figure 1: full-fiel l l l I r S r R r X y K K K T T        is not yet clea asticity-induce Frattura ed Inte iv        2B E z  1/2 1/2Dz ln = s = f = h = a = c F = u P model in th digital image T-stress as fo onents Tx in x Displacement ld fitting betwe a crack 29.3    0 0 0 im 2 lim 2 lim 2 r r r r r r C F                 ar whether the ed growth rat egrità Strutturale  2 2B E z  1/2 1/2Ez ln 1/22nz Dz  shear modulu function of Po horizontal and auxiliary funct complex coor unknown coe hese terms allo correlation t ollows (note t x-direction an t field around a een model and mm long und    3 2 2 y xy y Eln r         e CJP model, te perturbatio e, 14 (2010) 5-1 1 1 2 24z Ez  4 C F nz    2 C F z     us, MPa oisson’s ratio d vertical disp tions in Musk rdinate in the fficients and ows direct co techniques (F that when usi nd Ty in y-dire a crack tip mea d experimental er a load of 12       3 2 2 3 r A B D E       , based on the ons, or lead to 16; DOI: 10.3221/ 1 22 C Ez lnz     o ν placements khelishvili‘s m plane z=x+iy D+E = 0 omparison wi Fig. 1). Expr ing displacem ection): asured using D data. A 2 mm 20 N. The mea 3 8A B E  e plastic inclu o a reconciliat /IGF-ESIS.14.01 4 C F z    model y ith full field c ressions can b ment data rath DIC techniques m thick alumini asurement regi E usion concept tion of conflic crack tip disp be directly ob her than stres s. The pattern ium specimen i ion is 17.7 mm t, will provide cting views o placement fiel btained from ss data, the T of points is us is used which c m by 13.2 mm. e a means of c f plasticity-in (5) lds measured, Eq. 5 giving T-stress has to sed for the contains characterising nduced crack t , for g KF, o be g tip http://www.gruppofrattura.it http://dx.medra.org/10.3221/IGF-ESIS.14.01&auth=true shi fitt IN dep dis stru thr Th sam Th and [19 asy can gro sus An of allo ligh inc bor fati me lev inc In par I ielding. It do ting error whe NTERGRANU ntergranula alloys, e.g. consequen pendent on t locations, wh ucture of a ½ ree 1/6[1 1 1] his leads to sl me as that req Figur period he motion of s d {1 1 2} slip 9] and ultra-lo ymmetry give n then form a owth along ex sceptible alloy n interesting e bcc steels us oys have to b ht weight and creased forma ron and nitro igue loading, echanism outl vels of P and creased P and the case of IF rticularly duri I es, however, en compared ULAR FATIGU ar faceting du certain α-iron nce of crystal temperature, hich are less ½[111] screw fractional dis lip asymmetry quired to mov re 2: Core of a dically repeating The arrows ar screw disloca p planes. Int ow interstitial s rise to shap along grain b xtended crack ys subjected t example of th sed in the au balance severa d are likely to ability and dee ogen, typically , however, l lined above. Mn in solid d lower interst F steels, desp ing crack init capture influ with photoel UE uring fatigue ns and ultra-l l structure a strain rate an mobile than dislocation in locations whi y whereby th ve it in the op ½[111] screw g the three (11 re the relative ( ations hence d terstitial atom l atom conten pe changes of boundaries w k paths plasti to fully revers his phenomen utomotive ind al conflicting o be subject t ep-drawing c y 10-200 wt p low interstitia IG cracking solution. Su titial C, B or N ite plastic def tiation and lo M. N. James e uences of plas lastic full-field is a second low carbon st and dislocatio nd interstitial n non-screw n a bcc alloy ich also sprea he shear stres pposite directi dislocation pa 1) layers (distin (screw) displac depends on st ms present in nt (e.g. C, B, N f bcc grains u which favours ic deformatio sed loading in non occurs in dustry for for requirements to reversed cy apability are a ppm (0.001 w al content ( g may also be usceptibility t N [16]. formation bei ong life fatig et alii, Frattura e ticity that hav d fringe data. plasticity-ind teels with a b on movemen l atom conte dislocations is non-planar ad asymmetri ss to move a ion on the sa arallel to the pl nguished by di cements of neig tress-assisted the cores of N) would the undergoing fu the nucleatio on may be str n high cycle fa n interstitial-fr rming thin ga s, i.e. deep-dr yclic loading assisted by ve wt % to 0.02 w < 40 ppm) e promoted w to brittle frac ing strongly l gue, the fatigu ed Integrità Strut ve, up to now duced phenom ody-centred c nt [16]. Slip ent and are g and which m r, lying in thr ically on three dislocation i ame plane. ane of the figu ifferent colour ghbouring atom d thermally ac f screw disloc erefore prom ully reversed on of intergr rongly localis atigue where l ree (IF) steels auge sheet b rawing capabi in service. T ery low amou wt %). At th promotes IG with high stre cture has bee localised at gr ue performan tturale, 14 (2010 w, largely been menon that o cubic (bcc) cr p mechanism governed by make cross-sl ree {1 1 1} p e {1 1 2} plan in one directi ure. The atomic ed atoms) alon ms along the disl tivated gener cations appare mote slip asym cyclic deform ranular fatigu sed within gra levels of plas s which const ody panels. ility, fatigue r The conflict in unts of interst he small plast G cracking ength IF stee en shown to rain boundari nce is little d 0) 5-16; DOI: 10 n ignored and occurs infrequ rystal structur ms in bcc all the behaviou lip more diff lanes (Fig. 2) nes in the twi ion on a slip c block is form ng the dislocati location line [17] ration of kink ently make th mmetry in bcc mation. Stres e cracks. Du ain boundarie tic strain rang titute one of t In performa resistance, ten n requiremen titial elements tic strains typ through the el grades con be higher in ies, which lea different to o 0.3221/IGF-ESIS. d gives a lowe uently in spe re, and is a di loys are stro ur of long sc ficult. The c ). It spreads inning sense plane is not med by ion line. ]. k pairs on {1 his process ea c alloys. This ss concentrati uring subsequ es, particularl ge are low. the major gro ance terms, th nsile strength nts arises beca s such as carb ical of high c slip asymm ntaining increa n the presenc ds to IG face other compar 14.01 9 er cific irect ngly crew core into [18]. t the 1 0} asier slip ions uent ly in oups hese and ause bon, cycle metry ased e of eting rable http://www.gruppofrattura.it http://dx.medra.org/10.3221/IGF-ESIS.14.01&auth=true M.N 10 allo IG to e RE dif the num stre of wa wel Th stru par res per fati suc fro slip cyc loa We ass to eng sur of Fro A s R N. James et alii, oys which do G facets on a f either critical ESIDUAL STR esidual consequ of the y fferent distanc erefore also v mber of ways ess and fatigu structural par ke effects, lo lding), mecha Figure 3: IG heir magnitud uctures produ rticularly in th idual stress rformance thr igue ‘quality’ ch as the initi om interface c p processes. clic loading, t ad. elding is the sessment for w propose very gineering crit rface measure measurement om the 1970s synchrotron l R Frattura ed Inte o not exhibit fracture surfa or sub-critica RESSES AND stresses aris uence of man yield or proo ces over whic varies with typ s, including c ue crack grow rts. They als ocal phase tra anical propert faceting near t des can be hig uced under n he presence o profiles dur rough, for ex of the comp iation of fatig coherency, e.g Despite the there is still a most comm welded joints y conservativ ticality of def ements, e.g. u ts, alongside a s onwards, th light source i egrità Strutturale such IG face ace are usually al cracking w D WELDS e as a conse nufacturing an of strength. ch the residu pe, nature and changes to lo wth. These st o occur as a ansformation ties, microstru the crack initiat and 0. ghly variable; nominally sim of stress conc ring service xample, peeni ponent [23]. gue cracks and g. of intermet widespread e a lack of accu monly used st s often has a ve ways of de fects. A larg using low ener an ‘innate’ co e available X- s a form of p e, 14 (2010) 5-1 eting during c y an indicatio would be lowe equence of m nd fabrication These region al stresses sel d origin [20]. ad eccentricit tresses often a consequence ns), and are p ucture and ge tion site in an .013Ti. The st ; both from p milar condition entrators suc [21]. Comp ng [22] or co Type II stres d corrosion p tallic particles existence and urate 3D info tructural joini deciding influ ealing with re ge contributio rgy X-ray sou ontribution to -ray intensity particle accele 16; DOI: 10.3221/ crack initiatio on that some ered. Fig. 3 sh misfit betwee n processes, w ns of misfit c lf-equilibrate. Type I mac ty and failure arise from no e of the crack particularly in eometry of th IF steel contai teel has a yield place-to-plac ns. The exter h as weld toe pressive resid ld-working te sses are interg processes. Ty s and regions, d frequent us ormation on t ing process a uence on the esidual stress on to this un urces, impreci o scatter from y increased dr erator in whic /IGF-ESIS.14.01 n and growth form of emb hows typical I en various re with magnitud can occur wi . Their influe rostresses can e stress durin on-uniform pl k growth proc nfluenced by he componen ining 0.001C, 0 strength of 17 e within the rnal applicatio es, defects and dual stresses echniques, wh granular in sc ype III stresse , and from di e of residual the magnitud and the resid analysis outc in fracture m ncertainty ari ision in hole d m the welding amatically as ch particles (u h [16]. This rittlement ha IG faceting o egions [20] an des that local ith several di ence on mech n affect the p ng buckling, a lastic deform cess itself (cra thermal proc t or part. 0.380Mn, 0.004 74 MPa. component, on of cycles o d cracks, lead s are routine hich are often cale and influ es are of the slocation stre stresses in e de and re-dist dual stress di come [24]. T mechanics ass ises from dat drilling param process [24]. synchrotron usually electro is unusual, as as occurred an observed in th nd are hence lly are often a ifferent size s hanical perfo performance o and influence mation or from ack tip plastic cesses (e.g. h 4Si, 0.008P, 0.0 and between of load, displ ds to significan ely used to n considered uence aspects order of atom ess fields, and enhancing per tribution (or r istribution as Thus fatigue d sessments of ta limitations meters and rel light sources ons) are initia s the presenc nd that resista hese alloys. e an inescap a high propor scales and he ormance of al of structures s on the frac m assembly m c zone and c heat treatmen 005S, 0.018Nb n component lacement or h nt changes in enhance ser as improving s of performa mic size and a d influence pla rformance un relaxation) un ssumed in de design codes t remanent lif s associated w latively small were develop ally accelerate ce of ance pable rtion ence lloys in a cture misfit rack nt or b ts or heat, n the rvice g the ance arise astic nder nder efect tend fe or with sets ped. ed in http://www.gruppofrattura.it http://dx.medra.org/10.3221/IGF-ESIS.14.01&auth=true a l acc car mu elec see Syn Its Th loc a ty Ne of par wh em 0.1 spe ma it w dif Ne Pa In un Sc hy De Le linear acceler celerated (to refully synchr ulti-magnet in ctron beam a e Fig. 4 – with nchrotron rad advantages d  High br  High co  Low em  Wide tu  High br hese attributes cation ~ 10µm ypical experim eutron diffrac steel). The r rticularly whe hen waves en manating from Å to 1000 Å ecies or comp aterial. Such a will scatter u ffraction. Neu eutrons article beam (n teractions wit npaired electro attered by all ydrogen isotop eep penetratio ess intense be rator and the about 0.6x t ronized with t nsertion devi and convert s h energies in t diation is very derive from: rightness and ollimation, i.e mittance, i.e. t unability in en rilliance (pho Fi s, coupled wit m) capable of ment extendin ction is the ot required free en fission occ ncounter an m a reactor can Å, making th plex biopolym a neutron bea under a limite utron and syn neutral subato th the nuclei ons (in the sa elements, als pes on depth (bul eam measurin en injected in the speed of the travelling ices (‘‘undula some of its en the range of 2 y suitable for d high intensit e. small angula the product o nergy/wavele ton flux) igure 4: Electro th greatly imp f accommoda ng over sever ther widely u neutrons can curs. All qua array of obs n be slowed hem an ideal mers. One Å am can then b ed number o nchrotron dif omic particle) and the magn ample) so the light on lk studies of ng larger samp M. N. James e nto a storag light, equiva particle beam ators’’ and ‘‘w nergy into hi 20-400 keV). fast, accurate ty, many orde ar divergence of source cros ength omagnetic spe proved data a ating large and ral days. sed technique n be obtained antum particl stacles whose down and sel probe of ato Ångström (0. be used to pe of well-define ffraction tech ) netic moment nes like the samples) ples et alii, Frattura e e ring where alent to an en m. Third-gen wigglers’’) in igh energy ele e residual stre ers of magnitu e of the beam ss section and ctrum showing analysis softw d heavy comp e capable of d in a nuclea les can exhib e size is com lected by thei omic and mo 1 nm) is the erform a diffr ed angles acc niques can pr t of Synch Ligh Inter the s Main Smal Very ed Integrità Strut e they are m nergy of 6 G neration synch straight sect ectromagnetic ess measurem ude greater th m d solid angle o g the region of ware and auto ponents, allow yielding data ar reactor whe bit wave phen mparable with ir speed such olecular struc typical separ raction experi cording to th rovide compl hrotron radiatio ht beam (elect ractions with sample) nly scattered b ll penetration y intense beam tturale, 14 (2010 made to circu GeV) in an e hrotron X-ray tions of the c radiation (‘h ments through han with conv of emission is f visible light [2 omated 3D st w large sets o through thic ere they are s nomena such h the wavele h that their w ctures, either ration betwee iment; in imp he same Brag lementary info on tromagnetic w the electrons by heavy elem n depth (surfa m measuring 0) 5-16; DOI: 10 ulate via mag electric field. y sources are storage ring hard’ or high h up to about ventional X-r s small 25]. ages (with pr of strain data ck specimens set free throu h as diffractio ength. A be avelength lies in the form en atoms in a pinging on a c gg's law that formation: wave) s surrounding ments ace studies of small or ultra 0.3221/IGF-ESIS. gnetic fields Both fields designed aro which bend h energy X-ra t 10 mm of s rays X-ray tub recision of sp to be acquire (up to ≈ 50 ugh nuclei de on, which oc eam of neutr s in a range f of single ato a solid crystal crystalline sam t describes X g the nuclei (i f samples) a-dilute sampl 14.01 11 and s are ound the ays – steel. bes patial ed in mm ecay, curs rons from omic lline mple X-ray n les http://www.gruppofrattura.it http://dx.medra.org/10.3221/IGF-ESIS.14.01&auth=true M.N 12 Ap     Sim ana sca the Th wel Lau wel Th sup tha pro stre stre of dif N. James et alii, pplications: Magnetic st Organic stru Bulk studies Low-energy milar improve alysis for high ales for most e neutron or s he utility of n lds on the so ue-Langevin lding using a hese repair w perimposed o an the parent ocesses, simu ess corrosion ess, and it is c these various ffraction inten Figur Frattura ed Inte ructures and uctures using s (strains, exc y spectroscop ements to th h intensity ne metallic alloy synchrotron i neutron diffra ophisticated 6 in Grenoble utogenous fr welds were m on convention t plate. The ulating the or n cracking (SC clearly import s welds are sh nsities, requiri Figure 5 re 6: Illustratio egrità Strutturale excitations g the H-D iso citations) py, e.g. molecu hose found w eutron source ys. It is now instrument. action is easily 6-axis hexapo e, France. T riction stir we ade in annea nal V-prepara e original but riginal constru CC) during se tant to know hown in Fig. ing long coun 5: Measuremen on of repair we e, 14 (2010) 5-1 tope effect ular vibration with synchrot es, mean that w also possibl y demonstrat od Stewart pla This experime elding and las aled SA240 G ation butt we tt welds wer uction metho ervice in the p how repair w . 6. It is wor nt times for e nt of residual st eld procedures of fusion w 16; DOI: 10.3221/ ns App  P  F  S  H e tron radiation residual strai le to apply in ted; Fig. 5 sh atform of the ent was conc ser beam weld Grade 304L elds. They wo re made usin ods used in t power genera welding proce rth noting th ach measurem tresses in 16 m superimposed welds in 304L st /IGF-ESIS.14.01 lications: Protein-crysta Fast chemical Surface studie High-energy s electron energ n sources, in in and stress n-situ loading hows residual e SALSA neu cerned with a ding with 316 austenitic sta ould be expe ng either subm the stainless s ation industry edures will aff at texturing i ment [26]. mm thick plates d on SCC crack tainless steel. al structures l reactions es (defects, co spectroscopy gy-levels n automated data can be o to specimen l stresses bein utron diffract assessing the 6L and nicke ainless steel p ected to displ merged arc o steel tanks. y, which is dri fect the residu in austenitic w s of 304L stain ks in the heat-a orrosion) , e.g. measure sample posit obtained over s whilst they ng measured tion instrume e influences o el-based powd plate 10 mm lay better cor or manual m Stainless stee iven by high ual stress dist weld metals c nless steel. affected zone ( ements of tioning and r a wide rang are mounted in stainless s ent at the Ins of overlay re der consumab m thick and w rrosion resista metal arc weld el can experie levels of resi tribution. De can lead to w (HAZ) data ge of d on steel titut epair bles. were ance ding ence dual etails weak http://www.gruppofrattura.it http://dx.medra.org/10.3221/IGF-ESIS.14.01&auth=true Ne ver for Th spa ove stre hig but site 304 trea spe Fig eutron diffra rtical and ho r measuring he 3D stress s acing of 4 mm erlay weld sup ess profiles in ghest tensile r tt weld, wher e welds made 4L. The pos atment of the ecimen. gure 8a: Residu action data w orizontal slit strains in th tate was mea m at depths perimposed o n the three c residual stress e the FS weld e in the stainl ssibility of SC e weld region Figure 7: ual stress conto were measur t sizes of 1.1 he direction t asured with a of 2 mm, 5 on a friction coordinate di ses in the ove d was located less steel plat CC should th n would furth : Two 304L sta dete our maps for F M. N. James e ed using the 1 mm, and a transverse to spacing of 2 mm and 8 m stir weld) are irections mea erlay sample o . Peak stress te (Fig. 9), wh herefore be g her reduce re ainless steel we ermination of t FSW and laser b et alii, Frattura e e {3 1 1} pla a neutron w o the weld is mm from the mm into the p e shown as co asured at a de occur at abou es in the repa hilst the corr greatly reduce esidual stresse elds shown in p the strains tran beam weld ove ed Integrità Strut anes in the al wavelength o s shown in F e centre-line plate. Residu ontour maps epth of 1 mm ut 5 mm to th air overlay are rosion resistan ed after this es and these position on the nsverse to the w erlay on a V-bu tturale, 14 (2010 lloy giving a of 1.5488 Å. Fig. 7. of the weld a ual stress dat in Fig. 8a, wh m below the he side of the e lower than t nce of the ov repair proced can be re-me e SALSA instru weld. utt weld in 10 m 0) 5-16; DOI: 10 a diffraction The typica at a depth of a for specim hilst Fig. 8b g surface of t e centre-line o those occurri verlay alloy is dure has bee easured after ument for mm plate of 30 0.3221/IGF-ESIS. angle of 91. al sample set 1 mm and wi en 3 (laser b gives the resi the overlay. of the origina ng in the orig s higher than en applied. H heat treating 04L stainless s 14.01 13 35º, t-up ith a eam dual The al V- ginal n the Heat g the steel. http://www.gruppofrattura.it http://dx.medra.org/10.3221/IGF-ESIS.14.01&auth=true M.N 14 It i ser cali In latt reg me fro Th inte equ phe N. James et alii, is clear that n rvice welds a ibration of th measuring re tice spacing d gion. An im easurements o om a number his brief discu erface betwee ually require enomena. Fi Frattura ed Inte Figure 8b: neutron and s and other com he accuracy of esidual stresse d0, which is a mportant aspe on toothcomb of relevant p ussion has, h en metallurgy an understa igure 9: Residu egrità Strutturale : Residual stres synchrotron d mponents, p f the predictiv es using diffr ffected by fac ect of diffrac b specimens c ositions in th hopefully, ind y and mechan anding of th ual stress conto e, 14 (2010) 5-1 ss profiles at a diffraction ar particularly if ve model. raction techni ctors such as ction-based m cut across the he plate. dicated that n nics in materi he effect of ours for an orig 16; DOI: 10.3221/ depth of 1 mm e very power the results a iques, crystal s composition measurement e weld region not only are ials performan crystal struc ginal site weld /IGF-ESIS.14.01 m below the su rful technique are linked to lattice spacin n and micros ts is therefor n [27] or via u residual stre nce, but also cture and mi made in the 10 urface of the w es for assessin o finite eleme ng is determi tructure and re determina use of small c esses an inter that their me icrostructure 0 mm 304L sta weld overlay. ng 3D residu ent modellin ined relative t hence can va ation of d0, o ubes (perhap resting demo easurement a on continu ainless steel pla ual stress field g and used to the strain- ary across a w often by mak ps 2x2x2 mm) onstration of nd interpreta uum and phy ate. ds in as a -free weld king ) cut f the ation ysics http://www.gruppofrattura.it http://dx.medra.org/10.3221/IGF-ESIS.14.01&auth=true CO und exp und wh me AC RE [1] [2] [3] [4] [5] [6] [7] [8] [9] [10 [11 [12 [13 [14 [15 [16 [17 [18 [19 [20 [21 [22 [23 [24 [25 T T ONCLUSION his pape dominat plasticity derstanding o perience of th derstanding o hilst others ar esoscopic mat CKNOWLEDG he awar assistanc Danie H EFERENCES CEGB R6, Gloucester, BS 7910:20 Institution ( J. G. A. de G A. Griffith, E. Inglis, Tr H. M. West G. R. Irwin P. C. Paris, M. N. Jame 2403. 0] R. H. Chris 1] W. Elber, E 2] C. J. Christo 3] M. N. Jam Developme 4] M. N. Jam Micromech 5] M. L. Willia 6] M. N. Jame 7] http://cnls. 8] D. Hull, D. 9] A. Seeger, P 0] P. J. Wither 1] M. N. Jame Failure Ana 2] M. N. Jame 3] M. Ofsthun 4] P. J. Boucha 5] Wikipedia, 2010. T T NS er has presen ted or compr y and its in of the interfa he author, ov of this interfa re glaringly ob terial perform GEMENTS rd of beam ce from the b Hattingh and D S Revision 4, A , England, (A 005, Guide to (2005). ISBN Graaf, Applie The phenom rans. Instituti tergaard, Proc n, J. App. Mec R. E. Gomez es, In: Procs 9 tensen, Appl. Engng Fract. M opher, M. N. mes, C. J. Chr ent and Reliab mes, C. J. Ch hanics of Frac ams, J. Appl. M es, Engng Fra .lanl.gov/~gr J. Bacon, , In Phil. Mag. Let rs, H. K. D. H es, D. J. Hug al., 14 (2007) 3 es, M. Newby n, Int. J. Fatig ard, Int. J. 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Fract., 148 on, In: Procs 2010); Advan rson, In: Pr o be publishe ssed on 5 Sep n, Pergamon (2000) 355. attingh, D. A a Engng, 2 (1) 52. /wiki/Electro tturale, 14 (2010 the mechani allurgical fact ing structura engineering a e, most servi s that occur a nsequences if anics analysis s gratefully a ble assistance cknowledged ng defects, Br s in metallic es, A 221 (192 y of Washingt o et al), Austra 8 (2007) 361. s 2nd Int. Co nced Mats Res ocs 6th Int. ed in Key Eng ptember 2009 Press, Oxfor Asquith, J. R. ) (2010) 441. omagnetic_ra 0) 5-16; DOI: 10 ical performa tors, focussin al integrity re and materials ice failures ar at this interfac f the reality o of structures acknowledged e of Philip D d. ritish Energy structures, B 20)163. ton, 13(1) (19 alia, Pergamo onf. on Adva s., 118-120 (2 Conf. on M gng Mats. 9. d (1984) . Yates, P. J. adiation, acce 0.3221/IGF-ESIS. ance of meta ng particularly equires a so s science. In rise from a p ce are very su of microscopi s. d, together w oubell, Profe Generation British Stand 61) 9. on Press, 5 (19 ances in Prod 2010) 1. Mats Struct. Webster, En essed on 24 J 14.01 15 als is y on ound n the poor ubtle ic or with essor Ltd, ards 997) duct and ngng June http://www.gruppofrattura.it http://dx.medra.org/10.3221/IGF-ESIS.14.01&auth=true M.N 16 [26 [27 N. James et alii, 6] S. Okido, K 7] D. J. Hughe Frattura ed Inte K. Saito, H. Su es, M. N. Jam egrità Strutturale uzuki, Mats S mes, D. G. Ha e, 14 (2010) 5-1 Sci. Forum, 52 attingh, P. J. W 16; DOI: 10.3221/ 24-25 (2006) Webster, J. N /IGF-ESIS.14.01 697. eutron Res., 11 (2003) 289 9. http://www.gruppofrattura.it http://dx.medra.org/10.3221/IGF-ESIS.14.01&auth=true << /ASCII85EncodePages false /AllowTransparency false /AutoPositionEPSFiles true /AutoRotatePages /None /Binding /Left /CalGrayProfile (Dot Gain 20%) /CalRGBProfile (sRGB IEC61966-2.1) /CalCMYKProfile (U.S. Web Coated \050SWOP\051 v2) /sRGBProfile (sRGB IEC61966-2.1) /CannotEmbedFontPolicy /Error /CompatibilityLevel 1.4 /CompressObjects /Tags /CompressPages true /ConvertImagesToIndexed true /PassThroughJPEGImages true /CreateJobTicket false /DefaultRenderingIntent /Default /DetectBlends true /DetectCurves 0.0000 /ColorConversionStrategy /CMYK /DoThumbnails false /EmbedAllFonts true /EmbedOpenType false /ParseICCProfilesInComments true /EmbedJobOptions true /DSCReportingLevel 0 /EmitDSCWarnings false /EndPage -1 /ImageMemory 1048576 /LockDistillerParams false /MaxSubsetPct 100 /Optimize true /OPM 1 /ParseDSCComments true /ParseDSCCommentsForDocInfo true /PreserveCopyPage true /PreserveDICMYKValues true /PreserveEPSInfo true /PreserveFlatness true /PreserveHalftoneInfo false /PreserveOPIComments true /PreserveOverprintSettings true /StartPage 1 /SubsetFonts true /TransferFunctionInfo /Apply /UCRandBGInfo /Preserve /UsePrologue false /ColorSettingsFile () /AlwaysEmbed [ true ] /NeverEmbed [ true ] /AntiAliasColorImages false /CropColorImages true /ColorImageMinResolution 300 /ColorImageMinResolutionPolicy /OK /DownsampleColorImages true /ColorImageDownsampleType /Bicubic /ColorImageResolution 300 /ColorImageDepth -1 /ColorImageMinDownsampleDepth 1 /ColorImageDownsampleThreshold 1.50000 /EncodeColorImages true /ColorImageFilter /DCTEncode /AutoFilterColorImages true /ColorImageAutoFilterStrategy /JPEG /ColorACSImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /ColorImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /JPEG2000ColorACSImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /JPEG2000ColorImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /AntiAliasGrayImages false /CropGrayImages true /GrayImageMinResolution 300 /GrayImageMinResolutionPolicy /OK /DownsampleGrayImages true /GrayImageDownsampleType /Bicubic /GrayImageResolution 300 /GrayImageDepth -1 /GrayImageMinDownsampleDepth 2 /GrayImageDownsampleThreshold 1.50000 /EncodeGrayImages true /GrayImageFilter /DCTEncode /AutoFilterGrayImages true /GrayImageAutoFilterStrategy /JPEG /GrayACSImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /GrayImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /JPEG2000GrayACSImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /JPEG2000GrayImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /AntiAliasMonoImages false /CropMonoImages true /MonoImageMinResolution 1200 /MonoImageMinResolutionPolicy /OK /DownsampleMonoImages true /MonoImageDownsampleType /Bicubic /MonoImageResolution 1200 /MonoImageDepth -1 /MonoImageDownsampleThreshold 1.50000 /EncodeMonoImages true /MonoImageFilter /CCITTFaxEncode /MonoImageDict << /K -1 >> /AllowPSXObjects false /CheckCompliance [ /None ] /PDFX1aCheck false /PDFX3Check false /PDFXCompliantPDFOnly false /PDFXNoTrimBoxError true /PDFXTrimBoxToMediaBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXSetBleedBoxToMediaBox true /PDFXBleedBoxToTrimBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXOutputIntentProfile () /PDFXOutputConditionIdentifier () /PDFXOutputCondition () /PDFXRegistryName () /PDFXTrapped /False /CreateJDFFile false /Description << /ARA /BGR /CHS /CHT /CZE /DAN /DEU /ESP /ETI /FRA /GRE /HEB /HRV (Za stvaranje Adobe PDF dokumenata najpogodnijih za visokokvalitetni ispis prije tiskanja koristite ove postavke. 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