Size effect on fracture energy of concrete

Wittmann, Folker H.; Mihashi, Hirozo; Nomura, Noriaki

doi:10.1016/0013-7944(90)90188-m

Cited by 125 publications

(54 citation statements)

References 5 publications

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“…A series of experiments with emphasis on the size effect was reported by Wittmann et al [4]. They tested geometrically similar specimens of three different sizes, with relative dimensions shown in Figure 3 medium and large, resp.…”

Section: Experimental Datamentioning

confidence: 96%

“…Wittmann et al [4] fitted their experimental load-displacement curves using a cohesive crack model with bilinear softening, and they determined the values of four parameters specifying the bilinear law. To obtain good fits, they needed to consider these parameters by different values for different sizes.…”

Section: Experimental Datamentioning

confidence: 99%

“…Even for a fixed specimen geometry and type of loading, fracture energy defined in this way depends on the specimen size, as reported e.g. in References [1][2][3][4], and therefore we will sometimes call it the nominal fracture energy. The size effect on nominal fracture energy should not be confused with the size effect on nominal strength [5], which can be satisfactorily reproduced by all models listed in the foregoing.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, Wittmann et al [4] proposed to consider the local dissipation density as a function of the distance from the specimen surface. With the corresponding position-dependent softening law, the size effect on fracture energy can be fitted, but the simplicity and beauty of the original model is lost.…”

Section: Introductionmentioning

confidence: 99%

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Size effect on fracture energy induced by non‐locality

Jirásek

Rolshoven

Grassl

2004

Num Anal Meth Geomechanics

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SUMMARYExperimental results available in the literature indicate that the nominal fracture energy of concrete (defined as total work of fracture divided by the ligament area) depends on the size of the specimen. Theoretical modelling of the size effect on nominal fracture energy based on a non-local constitutive model is attempted in this paper. The influence of various details of the integral-type non-local formulation, e.g. of the specific form of non-local averaging in the vicinity of a physical boundary, is studied and a physical explanation is provided. The numerical results are compared to experimental data for notched compact tension specimens, and conclusions are drawn for individual formulations. It is shown that the best agreement with experimentally observed trends is achieved if the notch is modelled as a layer of completely damaged material. Fitting of the size effects on both strength and fracture energy permits a unique identification of the model parameters.

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Section: Experimental Datamentioning

confidence: 96%

Section: Experimental Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Size effect on fracture energy induced by non‐locality

Jirásek

Rolshoven

Grassl

2004

Num Anal Meth Geomechanics

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“…The test results, obtained under careful laboratory control, were quite systematic, with only a small scatter of the measured failure loads (which was not larger than in compression tests of concrete cylinders). Further extensive studies of the size effect for concretes with normal aggregate size have later also been performed (Iguro et al 1985;Eligehausen et al 1988;Eligehausen and Sawade 1989;Walraven 1990;Marti 1989;Wittman, et al 1990;Bocca et at. 1990;.…”

Section: Nature Of Problemmentioning

confidence: 99%

Fracture Size Effect: Review of Evidence for Concrete Structures

Bažant

Ožbolt²,

Eligehausen³

1994

J. Struct. Eng.

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The paper reviews experimental evidence on the size effect caused by energy release due to fracture growth during brittle failures of concrete structures. The experimental evidence has by now become quite extensive. The size effect is verified for diagonal shear failure and torsional failure of longitudinally reinforced beams without stirrups, punching shear failure of slabs, pull-out failures of deformed bars and of headed anchors, failure of short and slender tied columns, double-punch compression failure and for part of the range also the splitting failure of concrete cylinders in the Brazilian test. Although much of this experimental evidence has been obtained with smaller laboratory specimens and concrete of reduced aggregate size, some significant evidence now also exists for normal-size structures made with normal-size aggregate. There is also extensive and multifaceted theoretical support. A non local finite element code based on the microplane model is shown to be capable of correctly simulating the existing experimental data on the size effect. More experimental data for large structures with normal-size aggregate are needed to strengthen the existing verification and improve the calibration of the theory. NATURE OF PROBLEMAs a result of many important studies, including Humphreys (1957), Rusch et al. (1962), Leonhardt and Walter (1962), Kani (1967), Bhal (1968, Hsu (1968), McMullen and Daniel (1972), Taylor (1972), Hillerborg et al. (1976), Walsh (1976), Walraven (1978,1990), Chana (1981, Petersson (1981), Reinhardt (1981a,b), Hawkins (1985), Iguro et al. (1985), Hillerborg (1985), Ingraffea (1985, Rots (1988Rots ( , 1992 and others, it has been known that failure of concrete structures exhibits a size effect. For a long time the size effect has been explained statistically as a consequence of the randomness of material strength, particularly by the fact that in a larger structure it is more likely to encounter a material point of smaller strength. Various existing test data on the size effect were interpreted in terms of Weibull weakest-link theory [e.g. Mihashi and Zaitsev (1981) and Mihashi (1983)]. Later, however, it was proposed (Bazant 1984(Bazant , 1986) that whenever the failure does not occur at the initiation of cracking, which represents most situations, the size effect should properly be explained by energy release caused by macrocrack growth, and that the randomness of strength plays only a negligible role [in detail see Bazant and Xi (1991)].The size effect, however, does not follow the classical, linear form of fracture mechanics, in which all the fracture process is presumed to be happening at one point-the crack tip. Rather, the size effect in concrete structures must be explained by a nonlinear form of fracture mechanics that takes into account the localization of damage into a fracture process zone lWalter P. Murphy Prof. of Civ. Engrg. and Mat. Sci., Northwestern Univ., Evanston, IL 6020S.2Res. Engr., Institut fUr Werkstoffe im Bauwesen, Stuttgart Univ., Germany. 3Prof., ...

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Scale effects on sea ice fracture

Mulmule

Dempsey

1999

Mech. Cohes.-Frict. Mater.

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A viscoelastic fictitious crack model has been applied in this paper to the analysis of large‐scale in situ sea ice tests. By matching the experimental response, a stress‐separation curve has been derived for the in situ response of sea ice. The importance of including time dependent deformations in sea ice fracture models is illustrated. The limitations of the fictitious crack model in reproducing the ‘stick‐slip’ crack growth typically observed in sea ice are revealed. Copyright © 1999 John Wiley & Sons, Ltd.

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Size effect on fracture energy of concrete

Cited by 125 publications

References 5 publications

Size effect on fracture energy induced by non‐locality

Size effect on fracture energy induced by non‐locality

Fracture Size Effect: Review of Evidence for Concrete Structures

Scale effects on sea ice fracture

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