An unsymmetric double cantilever beam test for interfacial fracture toughness determination

Sundararaman, V.; Davidson, Barry D.

doi:10.1016/s0020-7683(96)00055-8

Cited by 64 publications

(23 citation statements)

References 37 publications

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“…(A.14) to zero yields the normalised crosshead displacements [5,6]; b) cracked lap shear (CLS) [7]; c) un-symmetric double cantilever beam (U-DCB) [8]; d) single leg bend (SLB) [9]; e) four point bending (FPB) [10][11][12][13][14]; (f) single leg four point bending (SLFPB) [15]; (g) over-leg bending (OLB) [16]. …”

Section: A2 Limit Rotation Anglementioning

confidence: 99%

A cut-ply specimen for the mixed-mode fracture toughness and fatigue characterisation of FRPs

Charalambous

Allegri

Lander

et al. 2015

Composites Part A: Applied Science and Manufacturing

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The characterization of mixed-mode fracture toughness and fatigue delamination growth in fibrereinforced composites is crucial for assessing the integrity of structural elements in service. An asymmetric cut-ply coupon (ACP) loaded in four-point bending is here proposed to carry out the aforementioned characterisations. Analytical expressions of the energy release rate and mode-mixity for the ACP are derived and validated by means of finite element analysis. A fracture toughness and fatigue characterisation of the carbon/epoxy material IM7/8552 is carried out via ACP specimens. It is proved that the material data obtained from ACP specimens match those generated using ASTM standard mixed-mode bending (MMB) coupons. The main reason for the introduction of the ACP test resides in its applicability to characterisation scenarios where measuring the delamination length with optical means, as required for MMB coupons, is difficult. Such scenarios include the investigation of static and fatigue delamination growth at low and high temperatures, which requires the usage of environmental chambers. This poses significant constraints in terms of volume available for the test rigs, and, most importantly, limitations on visual access to observe delamination propagation.However, the manufacturing of ACP coupons is more complex than for MMB specimens and the testing requires several additional precautions that are here discussed in detail.

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Section: A2 Limit Rotation Anglementioning

confidence: 99%

A cut-ply specimen for the mixed-mode fracture toughness and fatigue characterisation of FRPs

Charalambous

Allegri

Lander

et al. 2015

Composites Part A: Applied Science and Manufacturing

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“…We do not believe this to be the case. The convention of showing the error in phase angle in degrees is also adopted in our other works, where tests that produce very small and very large phase angles are described [12,20,21]. …”

Section: Comparison Of Resultsmentioning

confidence: 99%

“…[9]; the relatively recent mixed-mode bending (MMB) test is perhaps the most widely accepted of these methods [10, 1 1]. However, by comparison with the results of [12], the MMB test will necessitate geometrically nonlinear analyses for most bimaterial specimen geometries.…”

mentioning

confidence: 99%

“…Despite this reasonable amount of prior use, this is the first time, to our knowledge, that a comprehensive study of this test has been performed for bimaterial specimens (Shim and Hong [19] considered homogenous isotropic and orthotropic specimens and performed a similar study to that presented herein). In another work [20], it is shown that the SLB test, along with two other newly proposed test methods, the unsymmetric double cantilever beam [12] and the unsymmetric end-notched flexure test [21 ], provide a means by which the fracture toughness of most bimaterial interfaces may be determined over a complete range of mode mixities. These three tests use relatively simple test specimen geometries, loading fixtures, and data reduction procedures.…”

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confidence: 99%

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A single leg bending test for interfacial fracture toughness determination

1996

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A single leg bending test is described and its suitability for interfacial fracture toughness testing is evaluated. The test specimen consists of a beam-type geometry comprised of two materials, one 'top' and one 'bottom,' with a split at one end along the bimaterial interface. A portion of the bottom material in the cracked section of the beam is removed and the geometry is loaded in three-point bending. Thus, the reaction force of the support at the cracked end is transmitted only into the material comprising the top portion of the beam. The test is analyzed by a crack tip element analysis and the resulting expressions for energy release rate and mode mixity are verified by comparison with finite element results. It is shown that, by varying the thicknesses of the two materials, the single leg bending test can be used to determine the fracture toughness of'most bimaterial interfaces over a reasonably wide range of mode mixities. I n t r o d u c t i o nInterfacial fracture is a problem of significant importance with wide-ranging practical applications. A few examples where interfacial fracture is of concern are delamination of laminated materials, adhesive failure of bonded structural assemblies, decohesion of coated surfaces, and fiber/matrix debonding in advanced composites. However, despite the large body of theoretical work that has been performed on this subject (for example, see the reviews in [1] and [2]), experimental investigations are, in many respects, still in their early stages.For those cases where the singular field is oscillatory, the slow progress of experimental work is likely due to the difficulty of designing a specimen and load fixture that:( 1 ) can accommodate a wide variety of material pairs, (2) can produce a wide range of mode mixities, (3) are both relatively easy and inexpensive to manufacture, and (4) preferably do not involve an excessively laborious analytical or numerical pi'ocedure to extract results.As reviewed in recent papers [1-4], a number of excellent test methods have been developed, however, none of these approaches fully satisfy all of the above 'requirements'. For those cases where the singular field is non-oscillatory, the development of test methods has primarily been driven by the need to characterize the delamination toughness of laminated materials. The double cantilever beam [5,6] and end-notched flexure tests [7,8] are wellestablished for use with these materials under pure mode I and mode II conditions, respectively. A number of mixed-mode tests have been used over the years, e.g. [9]; the relatively recent mixed-mode bending (MMB) test is perhaps the most widely accepted of these methods [10, 1 1]. However, by comparison with the results of [12], the MMB test will necessitate geometrically nonlinear analyses for most bimaterial specimen geometries.

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“…I/II modu mistoko haustura aztertzeko asmoz, beste saiakuntza konfigurazio batzuk proposatu dira. Adibidez, Habe Landatu Bikoitzeko Saiakuntza Ez-simetrikoa (Asymmetric Double-Cantilever Beam, ADCB), non pitzadura planoa laminatuaren erdiko planotik at dagoen eta pitzadura puntan hasten den karga mistoko egoera bat sortzen duen [8]. Szekrenyes-ek, I/II modu mistoa aztertzeko, saiakuntza konfigurazio batzuk proposatu ditu: aurretentsionatutako bi probeta, bata End Notched Flexure test (ENF) saiakuntzan oinarritua [9], eta bestea, End-Loaded Split (ELS) saiakuntzan oinarritua [10].…”

Section: Arloko Egoeraunclassified

Laminarteko hausturaren i/ii modu mistoa aztertzeko saiakuntza konfigurazio berri bat

Boyano

Osa²,

Fernandez-Gamiz³

et al. 2018

EKAIA

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Laburpena: Lan honetan, laminatu konpositeen I/II haustura modu mistoa aztertzeko, saiakuntza konfigurazio berri bat aurkezten da. Konfigurazioa End Notched Flexure saiakuntzan oinarrituta dago. Pitzaduraren bi besoen artean, metalezko arrabola bat sartzen da modu mistoa lortzearren. II modua kanpoko kargaren bidez lortzen da, eta I modua, arrabola bat sartuz pitzadura irekitzean lortzen da. Haustura aztertzeko, energia askatzearen tasa erabiltzen da. Haustura modu bakoitzari dagokion tasa, analitikoki kalkulatu ondoren, elementu finituen bidezko kalkuluetan lortutako emaitzekin erkatzen da. Lan esperimentalean, karbono zuntzez eta epoxi matrizez osatutako norabide bakarreko T300/F593 konpositea erabiltzen da. Pitzadura luzera egoki neurtuta dagoen egiaztatzen da, energia askatzearen tasaren balioak irudikatzen dira, eta haustura irizpide egokia aukeratu da. Gainera, GIc eta GIIc parametroak ere kalkulatzen dira.Hitz gakoak: laminarteko haustura, modu mistoa, energia askatzearen tasa, pitzadura neurketa.Abstract: This study describes a new test configuration, based on an End Notched Flexure test configuration. A metallic roller is inserted between the two arms of the crack in order to get a mixed mode fracture. The external load application gives the mode II, and the opening of the crack is get by means of the inserted roller. Energy release rate is the parameter used for analyzing interlaminar fracture. Each mode energy release rate is determined analytically and the results are compared with the ones obEkaia 34 (ale berezia 2018).indd 37 Ekaia 34 (ale berezia 2018).indd 37

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An unsymmetric double cantilever beam test for interfacial fracture toughness determination

Cited by 64 publications

References 37 publications

A cut-ply specimen for the mixed-mode fracture toughness and fatigue characterisation of FRPs

A cut-ply specimen for the mixed-mode fracture toughness and fatigue characterisation of FRPs

A single leg bending test for interfacial fracture toughness determination

Laminarteko hausturaren i/ii modu mistoa aztertzeko saiakuntza konfigurazio berri bat

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