CRACK RESISTANCE DETERMINATION FROM THE CHARPY IMPACT TEST

Transcription

1 CACK ESISTANCE DETEMINATION FOM THE CHAPY IMPACT TEST. Choudi nd J.L. Puzzolnte SCK CEN Boeretng 4 Mol, Belgium ABSTACT Mny engineers nd scientists investigted the possibility to correlte Chrpy impct energy with the frcture toughness. As result, mny empiricl correltions cn be found in literture. However, most of these correltions hve limited ppliction rnge due primrily to their empiricl bsis. ecently, simple procedure bsed on the proportionlity between crck length nd bsorbed energy ws provided to determine crck length from the lod-displcement test record. This procedure ws vlidted on lrge number of mterils using vrious crcked geometries. The min objective of this pper is to investigte the possibility to pply similr procedure to V-notched geometry, nmely the Chrpy specimen. Such n evlution would led to estimte the mteril crck resistnce from single Chrpy-V impct test. By performing number of well selected experiments, it is demonstrted tht such correltion exists nd cn led to n ccurte determintion of both sttic s well s dynmic crck resistnce from the simple Chrpy impct test. Introduction The Chrpy impct test is one of the most fscinting mechnicl tests s one try to extrct mny properties thn originlly expected. In prticulr, mny engineers nd scientists investigted the possibility to correlte Chrpy impct energy with the frcture toughness. Indeed, the Chrpy impct test is considered s chep nd esy test in comprison to the frcture toughness test which requires precrcking nd more sophisticted instrumenttion to monitor crck extension. As result, mny empiricl correltions were proposed in literture [1-8]. However, most of these correltions re limited in terms of rnge of ppliction due primrily to their empiricl bsis. Indeed, these correltions re estblished on experimentl dt including Chrpy impct energy, sttic frcture toughness nd sttic yield strength, lumping therefore effects relted to loding rte, notch cuity nd crck length-to-width rtio. We hve shown the limittion of such n empiricl tretment in [9], in prticulr the invribility of the Chrpy impct energy t upper shelf while sttic frcture toughness decreses with incresing temperture. ecently, simple procedure ws provided to determine crck length from the lod-displcement test record [1]. The bsic underlying ide is tht crck length is proportionl to the squre of bsorbed energy. This procedure ws vlidted on lrge number of mterils using vrious crcked geometries. It ws lso demonstrted to be pplicble to shllow crck configurtions s well s lrge crck extensions [1-11]. The min objective of this pper is to investigte the possibility to pply similr procedure to V-notched geometry, nmely the Chrpy V-notched specimen, to determine the qusi-sttic crck resistnce. It ws shown, in n ccompnying pper [9], tht there re serious indictions tht re supporting such derivtion. Three effects must be considered Effect of the notch/crck cuity: in the Chrpy impct specimen, the V-notch rdius is.5 mm, which is significntly lrger thn the infinitely smll crck tip rdius ( ); Effect of the notch/crck depth to width rtio: in the Chrpy impct specimen, the notch depth to width rtio is. mm while it is close to.5 for frcture mechnics specimens; Effect of the loding rte: the Chrpy impct test is dynmic while frcture mechnics tests re qusi-sttic. In order to correctly tke these effects into ccount, we performed number of dedicted tests to derive the individul effects. In the following, the energy normliztion procedure will be briefly reclled nd dditionl informtion on how it cn be pplied to the instrumented Chrpy impct test will be given.

2 Crck resistnce determintion procedure The crck resistnce behvior is obtined using the following procedure. The J-integrl clcultion is bsed on the ASTM E- 18 stndrd [1] which, for the single edge bend geometry, gives the following eqution: J = K ( 1 ν ) E + J pl( i 1 ) η + W ( i 1 ) U ( i ) U B n ( i 1 ) ( i ) 1 W ( where U is the re under the lod-displcement curve, W, B, B n nd re the specimen width, thickness, net thickness nd crck length, respectively, nd K is the stress intensity fctor (liner elstic). The fctor η is tken equl to ; E is the Young modulus nd ν is the Poisson rtion. More detils on the J-integrl formultion cn be found in [1]. As it cn be seen, in eqution (1), the J-integrl is incrementlly evluted using the ctul crck length. It ws shown in [1] tht the crck extension cn be estimted from the bsorbed energy (re under the lod-displcement test record). As result, the crck extension cn be determined using eqution (3): finl U U finl U U init init ( i 1 ) i 1 ) () U init is the energy required for crck growth onset. As it will be seen lter, this threshold vlue corresponds to the onset of ductile crck initition. Below this energy, no crck extension occurs, nd therefore, = if U<U init. Once J-vlues re clculted, the ctul crck extension is re-clculted using eqution (3): = finl J J finl J J init init (3) As indicted in [9], this reltion reflects simply the proportionlity between the J vlue with its derivtive with respect to crck extension, nmely the tering resistnce (dj/d). Gioielli et l. [7] lso ssumed such reltion to derive the crck resistnce from Chrpy impct test. This procedure ssumes tht onset of crck initition occurs t lod between the generl yield (liner prt) nd the mximum lod crrying cpcity [9]. F init F gy + F mx = (4) This reltion stems from the correltion between the sher frcture ppernce nd the chrcteristic lods of n instrumented Chrpy impct test [13]. As result, eqution (1) for the J-integrl nd eqution (3) for the crck extension llow to construct the crck resistnce curve (-curve). It cn be shown tht this -curve follows prbolic eqution of the type: J = J + J (5) where J init is the J-vlue t the onset of ductile crcking nd J t mesures the tering resistnce. init This procedure ws extensively verified on number of mterils, geometries nd experimentl conditions [1-11]. Compred to other normliztion procedures, such s the one proposed in the ASTM stndrd [1], this one is more closely bsed on the ctul response of the mteril nd pplicble to specimens fully broken. The sme procedure cn be pplied to the notched rther thn crcked geometry, nmely the Chrpy-V smple under impct loding. Figure 1 shows the lod time test trces of Chrpy impct loded smples of MnMoNi55 t 5 nd 9 C nd A533B t 9 C. The im is to provide, using such test record, n estimtion of both qusi-sttic nd dynmic (impct) crck resistnce curves. However, number of dt mnipultions re needed to be ble to clculte the J-integrl. To determine the re under the lod displcement curve, s specified by eqution (1), the displcement, s(t), should be clculted using the following eqution: t (1)

3 s( t ) = t t v( t ) dt where v(t) is the ctul velocity of the impct hmmer given by: (6) t 1 v ( t ) = v F( t ) dt (7) m v nd m re, respectively, the initil velocity nd the mss of the impct hmmer, F(t) is the lod t time t. The bsorbed energy, U (i), cn then esily be clculted using eqution (8): t s U = F ds (8) For J-integrl clcultion, the sme formultion s eqution (1) is used except tht the fctor η is not constnt (s in deeply notched smples) but chnges with the crck configurtion. Indeed, for shllow crck, this fctor ws found to depend much on the crck length to width rtio nd the following formultion, due to Sumpter [14] ws dopted here: η = η = W 19.5 W W 3 W W <.8.8 Note tht the use of other formultions of the η-fctor tht re found in literture [15-16] do not ffect the conclusions tht will be drwn from the present work. (9) lod (kn) MnMoNi55 ; T test = 5 C MnMoNi55 ; T test = 9 C A533B (JSPS) ; T test = 9 C time (ms) Figure 1. Lod time test records of Chrpy impct tested specimens of MnMoNi55 nd A533B steels. Combining eqution (1) nd (9), the J-integrl vlue cn be evluted t ech dt point. However, in the J-formultion, eqution (1), the crck growth correction is not pplicble for very lrge crck extensions. Indeed, bove certin crck extension, the J-integrl vlue decreses with incresing crck extension. However, s it will be seen lter, good pproximtion cn be obtined by mintining the J-integrl level t its mximum vlue in the region of decresing J. It should be mentioned tht in prctice, frcture toughness tests re performed for limited crck extensions, generlly not exceeding 1% of the ligment.

4 Mterils nd experimentl conditions Two rector pressure vessel steels tht were extensively investigted t SCK CEN [13] were selected for the present investigtion. These mterils nd the test temperture conditions provide wide rnge of crck resistnce behvior. An A533B plte provided by the Jpn Society for the Promotion of Science (JSPS) which ws rtificilly embrittled by S nd P ddition. As result, the upper shelf energy is only 7 J nd the DBTT is round +35 C. The second steel is the Germn MnMoNi55 steel, equivlent to n A58 forging with n upper shelf energy of bout 18 J nd DBTT of -75 C; the DBTT being evluted t 41J impct energy level. The chemicl composition of the steels is given in Tble 1. Most of the tests performed here use the Chrpy geometry. The choice of this geometry ws motivted by three considertions. First, this geometry is used in the stndrdized notched br impct test. Second, it cn esily be tested stticlly s well s dynmiclly (impct). Finlly, this geometry, when deeply precrcked, ws proven to led to similr crck resistnce behvior s lrge compct tension specimens [17]. Other considertions such s its smll size nd its vilbility in rector pressure vessel surveillnce progrms could lso be indicted. Bsiclly, two configurtions were used, the V-notch Chrpy (stndrd Chrpy geometry), nd the precrcked Chrpy geometry with crck depth to width rtio close to.5. The stndrd Chrpy specimen, referred to s CVN, is mm³ three-point bend specimen with 45 V-notch of mm depth. The smples tht were ftigue precrcked refer to s PCCv. For the qusi-sttic tests, the specimens were loded in three-point bending on n electromechniclly-driven Instron mchine with slow displcement rte (few tenths of mm/min). For the dynmic tests, the Chrpy impct test mchine ws used, the vilble impct energy being dpted to produce the desired crck length. The J-rte corresponds to pproximtely 1 kj.m -.s -1 for the qusi-sttic tests nd to 1 5 kj.m -.s -1 for the dynmic tests. Further detils on the experimentl procedure cn be found in [9]. TABLE 1. Chemicl composition Mteril C Si P S Cr Mn Ni Cu Mo MnMoNi A533B (JSPS) As indicted bove, the mterils nd test tempertures were selected such s three very distinct crck resistnce curves could be obtined [9]. As result, the MnMoNi55 forging ws tested t 5 nd 9 C while the A533B (JSPS) plte ws tested t 9 C. This cn be clerly seen on Figure which compres the three crck resistnce curves. The tensile properties re given in Tble for both sttic nd dynmic loding rtes. TABLE. Tensile test results. mteril T test ( C) lod rte σ y (MP) σ u (MP) ε u (%) ε t (%) A (%) MnMoNi55 5 sttic MnMoNi55 5 dynmic MnMoNi55 9 sttic MnMoNi55 9 dynmic A533B (JSPS) 9 sttic A533B (JSPS) 9 dynmic To reduce the test mtrix, the tests were selected such s to provide seprte effects of ech vrible with the ultimte gol to provide the crck resistnce from the CVN impct test. A number of experimentl dt were lredy given in [9]. Here, few dditionl dt relted to the specimen configurtion effect, in prticulr the notch/crck cuity nd depth will be given.

5 1 MnMoNi55 ; T test = 5 C 75 J (kj/m²) 5 5 MnMoNi55 ; T test = 9 C A533B (JSPS) ; T test = 9 C crck extension (mm) 3 Figure. Comprtive crck resistnce behvior of MnMoNi55 nd A533B (JSPS). The min objective being the determintion of the crck resistnce (qusi-sttic nd dynmic) from the stndrd Chrpy impct test, it will be necessry to evlute both the notch versus crck effect nd the shllow versus deep crck configurtion. The tests will be ppropritely selected to evlute both effects. The crck resistnce curves t both sttic nd dynmic loding rtes were tken from [9]. The loding rte effect is ssumed to be similr to wht ws found in [9], nmely the proportionlity constnt α loding rte nd the squre of the yield strength rtio, σ σ dynmic y sttic y. As it will lso be seen here, the experimentl dt obtined here support such n ssumption. Focus of the experimentl work presented here is put on the effect of notch cuity nd notch/crck depth. The following tests were performed (see Figure 3): CVN low blow tests t sttic loding: the stndrd Chrpy specimens were loded in three-point slow bending up to vrious crck extensions, the bsorbed energies vrying between bout 4 to 11 J. PCCv low blow tests t impct loding: the precrcked Chrpy specimens with / /W.5 were impct loded with n vilble energy between bout 5 to 4 J. CVN impct ref. [9] effect of loding rte (sme geometry) CVN sttic [Tble 3] effect of notch/crck configurtion (t dynmic rte) effect of notch/crck configurtion (t sttic rte) PCCv sttic ref. [9] PCCv impct [Tble 4] effect of loding rte Figure 3. Schemtic digrm showing the combined effects of specimen configurtion nd loding rte.

6 esults The results of the vrious tests re given in Tbles 3 to 4. The dt of Tble 3 cn be used to relte the shllow notch (/W=.) of Chrpy specimen to the deep crck (/W=.5) of three-point bend specimen (precrcked Chrpy). The J- clcultion ccording to the procedure described bove led to the results shown in Figure 4. This Figure demonstrtes the possibility to use fully broken single specimen to describe the crck resistnce bsed on V-notch geometry. TABLE 3. Slow bend test results on Chrpy V-notched smples. mteril T W B U J MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi A533B (JSPS) A533B (JSPS) A533B (JSPS) A533B (JSPS) A533B (JSPS) A533B (JSPS) A533B (JSPS) A533B (JSPS) A533B (JSPS) A533B (JSPS) symbols : J- from sttic CVN (/W=.) solid lines : J from single sttic CVN (/W=.) MnMoNi55 T test = 5 C J CVN (kj/m²) MnMoNi55 T test = 9 C JSPS T test = 9 C ductile crck extension, (mm) Figure 4. J- curves from sttic CVN Chrpy V-notched specimens. Apprent high crck resistnce due to notch configurtion (twice higher toughness thn in Figure ).

7 In [9], the dynmic crck resistnce curves were obtined using single precrcked specimen. Most of the dt for which the procedure ws vlidted were qusi-sttic tests. Here, we performed number of tests (multiple specimen method) to demonstrte the pplicbility of the procedure to dynmic loding rte. The results re summrized in Tble 4 nd Figure 5 shows the good greement between the vrious smples.. TABLE 4. Impct test results on precrcked Chrpy smples. mteril T W B U J remrk MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi from [9] MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi MnMoNi from [9] A533B (JSPS) A533B (JSPS) A533B (JSPS) A533B (JSPS) A533B (JSPS) A533B (JSPS) from [9] A533B (JSPS) A533B (JSPS) MnMoNi55 ; 5 C MnMoNi55 ; 9 C A533B (JSPS) ; 9 C symbols : impct PCCv (/W.5) solid lines : J from single impct PCCv MnMoNi55 ; T test = 5 C J dynmic (kj/m²) 1 5 MnMoNi55 ; T test = 9 C A533B (JSPS) ; T test = 9 C ductile crck extension, (mm) 5 Figure 5. Dynmic crck resistnce. The solid lines bsed on single precrcked specimen.

8 Anlysis of the esults In the preceding section, it ws shown tht the procedure for crck resistnce determintion is dequte for both notched smples nd t dynmic loding rtes. It ws lso shown in [9] tht the sttic J -curve cn be derived from the dynmic one using the following eqution: dynmic σ sttic y dynmic J = α loding rte J (1) sttic σ y where the constnt α loding rte pproximtely equl to.46. This eqution, denoting the effect of loding rte on the loss of crck tip constrint, ws obtined with deep crcked smples. For shllow crcks, it is known tht n pprent crck resistnce elevtion is observed s result of loss of constrint [18]. We hve lso seen in [9] tht good correltion seems to exist between the V-notched geometry nd the crcked geometry. So, we cn dopt the sme strtegy s for the loding rte effect by introducing fctor tht ccounts for the crck configurtion effect (deep versus shllow crck). Similrly to eqution (9), one cn write: where α shllow>deep ccounts for the loss of constrint introduced by the shllow crck. deep crck shllow crck J = α shllow> deep J (11) Becuse of the crck blunting phenomenon tht occurs before frcture initition, it is ssumed tht the notch cuity (notch versus crck) will not hve significnt influence on the crck resistnce behvior. As it will be seen lter, this ssumption is resonble. Indeed, consistent results re obtined bsed on this ssumption. Experimentl vlidtion using shllow precrcked specimens is in progress for complete justifiction. Combining equtions (9) nd (1), one obtins the reltion llowing determintion of the sttic crck resistnce using the Chrpy impct test:: To obtin the dynmic crck resistnce, eqution (11) reduces to: dynmic σ sttic y CVN impct J = α rte α shllow deep J (1) loding > sttic σ y dynmic CVN impct J = α shllow> deep J (13) So, equtions (11) nd (1) cn be used to correlte the crck resistnce obtined from the Chrpy impct test with the sttic nd dynmic crck resistnce curves. The crck resistnce curve from Chrpy specimen cn esily be obtined from the instrumented Chrpy impct test. We cn determine the fctor α shllow>deep tht rtionlize the results. A unique fctor, rtionlizing ll experimentl result, ws found, α shllow>deep =.55. At sttic loding rte, Figure 6 shows the good greement between the Chrpy V- notch smple nd the precrcked geometry. As it cn be seen, ignoring the effect of notch cuity nd considering only the specimen configurtion, nmely shllow notch versus deep crck, both geometries led to very similr results. The sme sttic Chrpy V-notched results shown in Figure 6 re compred in Figure 7 to crck resistnce curve obtined using single Chrpy impct test. The greement is very good. For the dynmic crck resistnce, Figure 8 shows the precrcked Chrpy specimens re lso in very good greement with the crck resistnce derived from the Chrpy impct test, the ltter being obtined using eqution (1). Finlly, Figure 9, summrizing ll vilble dt, shows n excellent greement between the vrious geometries. This Figure clerly supports the cpbility determining both the sttic nd dynmic crck resistnce curves from single instrumented Chrpy impct test.

9 15 1 open symbols : unloding complince PCCv sttic (crck /W=.5) full symbols : sttic Chrpy V-notch (/W=.) MnMoNi55 T test = 5 C J sttic (kj/m²) MnMoNi55 T test = 9 C JSPS T test = 9 C ductile crck extension, (mm) Figure 6. Sttic Chrpy V-notch versus precrcked Chrpy (obtined using the unloding complince method). Crck configurtion effect is ccounted for through α deep>shllow symbols : CVN (/W=.) sttic solid lines : J from CVN impct MnMoNi55 T test = 5 C J sttic (kj/m²) MnMoNi55 T test = 9 C JSPS T test = 9 C ductile crck extension, (mm) Figure 7. Crck resistnce curve s derived from the sttic Chrpy V-notch geometry, ccounting for the crck configurtion effect through α deep>shllow.

10 J dynmic (kj/m²) symbols : PCCv (/W.5) impct solid lines : J from CVN impct MnMoNi55 T test = 9 C MnMoNi55 T test = 5 C JSPS T test = 9 C 1 3 ductile crck extension, (mm) 4 Figure 8. Dynmic crck resistnce behvior of MnMoNi55 nd A533B (JSPS). Solid lines re obtined from single Chrpy impct test while symbols designte the multiple PCCv specimen method closed symbols : CVN (/W=.) sttic open symbols : PCCv (/W.5) dynmic thick curves : J from CVN (/W=.) sttic thin curves : J from CVN (/W=.) impct dshed curves : J from sttic PCCv (/W.5) MnMoNi55 T test = 5 C J sttic (kj/m²) MnMoNi55 T test = 9 C JSPS T test = 9 C 1 3 ductile crck extension, (mm) Figure 9. Summry of the vrious crck resistnce curves of MnMoNi55 nd A533B (JSPS). Discussion A number of frcture toughness Chrpy upper shelf energy correltions were proposed in literture. A review of the different correltions cn be found in [4,8]. As lredy indicted in [9], the min drwbck of such correltions is their inbility to ccount for the decrese of sttic frcture toughness with incresing upper shelf temperture. Indeed, in the upper shelf regime, both dynmic frcture toughness nd Chrpy impct energy remin little or unffected by incresing test temperture, By contrst, t qusi-sttic loding rtes, both frcture toughness nd Chrpy energy decrese with incresing temperture. Nevertheless, it is interesting to compre our procedure with those proposed in literture, in prticulr Schindler [6], Gioielli et l. [7] nd Wllin [8] for which full J curve cn be drwn. To illustrte these comprisons, two J-prmeters were selected, J. nd J corresponding to. mm nd mm crck extension, respectively. The former corresponds to crck initition nd the second roughly to the tering cpcity. These prmeters were determined using frcture mechnics tests, nmely the deeply precrcked Chrpy specimens. These reference vlues re then compred to the vlues determined from single Chrpy impct test. As it cn be seen from Figure 1 for dynmic loding nd Figure 11 for qusi-sttic loding, the procedure

11 presented in this pper is clerly leds to better greement with the vlues determined with frcture toughness specimens. Note tht the uncertinty bounds shown on Figure 11 re equl to those given in [7] nd [8], nd they correspond to bout 3%-reltive uncertinty. It is importnt to emphsize tht these three correltions re bsed only on the totl bsorbed energy to fully frcture n 8 mm ligment. By contrst, our procedure is bsed on the full lod displcement curve. J dynmic from impct CVN (kj/m²) Schindler [6] this work closed symbols : J. mm open symbols : J mm 1: J dynmic bsed on frcture mechnics (kj/m²) Figure 1. Comprison with other correltions determining dynmic crck resistnce from the Chrpy impct test. J sttic from impct CVN (kj/m²) Gioielli et l. [7] Wllin [8] this work closed symbols : J. mm open symbols : J mm 1: J sttic bsed on frcture mechnics (kj/m²) Figure 11. Comprison with other correltions determining sttic crck resistnce from the Chrpy impct test. There re limittions of the procedure presented here, in prticulr the ppliction of eqution (13). These re minly relted to the constnts ccounting for notch/crck configurtion nd loding rte. These constnts were empiriclly estblished on the bsis of experimentl results. Therefore, ppliction to other mteril nd experimentl conditions will probbly need reevlution of thse constnts. Becuse these constnts were introduced to ccount for the loss of constrint, it will be very much interesting to relte these them directly to the ctul loss of constrint clcultions using finite element computtions. A number of such clcultions were lredy performed to evlute the loss of constrint induced by crck configurtion nd loding rte, for exmple [19-]. Anlyticl expressions cn then be estblished on the bsis of finite element of the form:

12 loss of constrint σ y = α = >,n, shllow deep α loding rte f, J& W E α (14) where ll importnt prmeters relted to mteril, crck configurtion nd loding rte re tken into ccount. Eqution (14) cn be fitted to the finite element results. For the specific cse of the mteril, specimen configurtion nd loding rte conditions investigted here, this function shoud led to loss of constrint constnt of bout.5. Conclusions This study hs demonstrted the possibility to ccurtely determine the crck resistnce behvior from the instrumented Chrpy impct test. The procedure is solely bsed on the instrumented Chrpy impct test record. Both dynmic nd sttic crck resistnce cn be derived with high ccurcy. Test temperture nd loding rte effects re correctly ccounted for by the constnts introduced to tke the induced loss of constrint into ccount. These constnts were experimentlly determined for the mteril, specimen configurtion nd loding rte conditions investigted here. But to increse the rnge of ppliction, better ccount of these effects would be possible by performing pproprite finite element clcultions tht cn be nlyticlly expressed s function of crck depth to width rtio nd loss of trixility. Acknowledgments The uthors grtefully cknowledge the technicl support of. Mertens, A. Pellettieri nd L. Vn Houdt. The steels, MnMoNi55 nd A533B (JSPS) were kindly provided by J. Heerens (GKSS) nd K. Onizw (JAEI), respectively. eferences 1. olfe S.T. nd Brsom, J.M., Frcture nd Ftigue Control in Structure Appliction of Frcture Mechnics, Prentice-Hll, Inc., Englewood Cliffs, New Jersey, olfe, S.T. nd Novk, S.., Slow-bend K Ic testing of medium-strength high-toughness steels, eview of Development in Plne Strin Frcture Toughness Testing, ASTM STP 463, Americn Society for Testing nd Mterils, , Brsom, J.M. nd olfe, S.T., Correltion between K Ic nd Chrpy V-notch test results in the trnsition temperture rnge, Impct Testing of Metls, ASTM STP 466, Americn Society for Testing nd Mterils, 81-3, Pisrski, H.G., A review of correltions relting Chrpy energy to K Ic, The Welding Institute eserch Bulletin, , December Ngeswr o B. nd Achry, A.., A computer study on evlution of frcture toughness from Chrpy V-notch impct energy nd reduction of re, Engineering Frcture Mechnics, Vol. 41, No. 1, 85-9, Schindler, H.J., Estimtion of the dynmic J- curve from single impct bending specimen, Proceedings of the 11 th Europen Conference on Frcture, ECF-11, Mechnisms nd Mechnics of Dmge nd Filure, J. Petit, Ed., Vol. II, 7-1, Gioielli, P.C., Lndes, J.D., Pris, J.D., Td, H. nd Loushin, L., Method for predicting J- curves from Chrpy impct energy, Ftigue nd Frcture Mechnics: 3 th Volume, ASTM STP 136, P.C. Pris nd K.L. Jerin, Eds., Americn Society for Testing nd Mterils, 61-68,. 8. Wllin, K., Low cost J- curve estimtion bsed on CVN upper shelf energy, Ftigue nd Frcture of Engineering Mterils nd Structures, 4, , Choudi,. nd Puzzolnte, J.L., Loding rte effect on ductile frcture, submitted to ECF-16, (in preprtion). 1. Choudi,., An energy-bsed crck extension formultion for crck resistnce chrcteriztion of ductile mterils, Journl of Testing nd Evlution, Vol. 3, No. 6, , Choudi,., "Crck resistnce determintion from the lod displcement test record", SCK CEN eport, -371, Mrch ASTM, E 18-1, Stndrd Test Method for Mesurement of Frcture Toughness, Annul Book of ASTM Stndrds, Section III, Metls Test Methods nd Anlyticl Procedures, Volume 3.1, Americn Society for Testing nd Mterils,. 13. Choudi,. nd Fbry, A., On the utiliztion of the instrumented Chrpy impct test for chrcterizing the flow nd frcture behvior of rector pressure vessel steels, From Chrpy to Present Impct Testing, edited by D. Frnçois nd A. Pineu, Elsevier, ,. 14. Sumpter, J.D.G., J c determintion for shllow notch welded bend specimens, Ftigue nd Frcture of Engineering Mterils nd Structures, Vol. 1, n 6, , Nevlinen, M. nd Wllin, K., The effect of crck depth nd bsolute thickness on frcture toughness of 3PB specimnes, Proceedings of the 1 th Europen Conference on Frcture, ECF-1, Structurl Integrity: Experiments, Models nd Applictions, K.H. Schwlbe nd C. Berger, Eds., Vol. II, , Sreenivsn, P.. nd Mnnn, S.L., Plstic η-fctor for three-point bend specimens: Anlysis of instrumented Chrpy impct test results for AISI 38 weld nd AISI 316 stinless steels, Interntionl Journl of Frcture, 11, 15-8,.

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