Discussion: A fractal model for simulating the formation of microcracks in the fracture process zone and a theoretical explanation of the size effect of the fracture energy of concrete

AbstractWe follow the accumulation of microscopic damage ahead the crack tip in paper. The fiber debonding process varies even within each specimen because of large variation in fiber and bond properties. In general, stiff and weakly bonded fibers tend to debond as a rigid body while ductile or well bonded fibers pull out gradually in a process that propagates from the crack line to the fiber ends. Particularly in the latter case the network ruptures coherently rather than through debonding of single fibers. Experimental analysis and simulations show that fracture energy correlates closely with the size of the fracture process zone (FPZ) irrespective the nature of the debonding process. Only the cases of low bonding and stiff fibers seem to make an exception in that FPZ can grow in size without a corresponding increase in fracture energy.

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902 Simulation of fracture process zone by focusing on microscopic tensile strength and fracture energy

The Proceedings of Ibaraki District Conference ◽

10.1299/jsmeibaraki.2011.19.229 ◽

2011 ◽

Vol 2011.19 (0) ◽

pp. 229-230

Author(s):

Shinya KAMINO ◽

Mao KURUMATANI

Keyword(s):

Tensile Strength ◽

Fracture Energy ◽

Fracture Process ◽

Fracture Process Zone ◽

Process Zone

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Effect Of Aggregate Content On Fracture Behavior Of Concrete

MRS Proceedings ◽

10.1557/proc-409-255 ◽

1995 ◽

Vol 409 ◽

Author(s):

Y. Xi ◽

F.E. Amparano ◽

Zongjin Li

Keyword(s):

Fracture Energy ◽

Fracture Process ◽

Fracture Behavior ◽

Fracture Process Zone ◽

Volume Fraction ◽

Process Zone ◽

Aggregate Content ◽

Grain Structures ◽

Point Bend ◽

Two Parameters

AbstractEffect of aggregate content on fracture behaviors of concrete is studied by testing on geometrically similar three-point bend beams. The results are analyzed by using a size effect method in which the fracture behavior of concrete is characterized by two parameters, fracture energy Gf and effective fracture process zone cf. Test results showed that with increasing volume fraction of aggregate in the range 45% - 75%: (1) the modulus of elasticity of concrete decreases slightly, (2) fracture energy Gf increases, but the rate is very small; (3) the size of the fracture process zone, cf, decreases, which may be explained by changes in coarseness of grain structures defined in terms of mosaic patterns.

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Fracture energy and fracture process zone

Matériaux et Constructions ◽

10.1007/bf02472590 ◽

1992 ◽

Vol 25 (6) ◽

pp. 319-326 ◽

Cited By ~ 144

Author(s):

X. -Z. Hu ◽

F. H. Wittmann

Keyword(s):

Fracture Energy ◽

Fracture Process ◽

Fracture Process Zone ◽

Process Zone

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Size effect analysis of quasi-brittle fracture with localizing gradient damage model

International Journal of Damage Mechanics ◽

10.1177/1056789520983872 ◽

2021 ◽

pp. 105678952098387

Author(s):

Yi Zhang ◽

Amit S. Shedbale ◽

Yixiang Gan ◽

Juhyuk Moon ◽

Leong H. Poh

Keyword(s):

Brittle Fracture ◽

Size Effect ◽

Fracture Process ◽

Fracture Process Zone ◽

Concrete Beams ◽

Process Zone ◽

Damage Zone ◽

Damage Model ◽

Lattice Models ◽

Gradient Enhancement

The size effect of a quasi-brittle fracture is associated with the size of fracture process zone relative to the structural characteristic length. In numerical simulations using damage models, the nonlocal enhancement is commonly adopted to regularize the softening response. However, the conventional nonlocal enhancement, both integral and gradient approaches, induces a spurious spreading of damage zone. Since the evolution of fracture process zone cannot be captured well, the conventional nonlocal enhancement cannot predict the size effect phenomenon accurately. In this paper, the localizing gradient enhancement is adopted to avoid the spurious spreading of damage. Considering the three-point bend test of concrete beams, it is demonstrated that the dissipation profiles obtained with the localizing gradient enhancement compare well with those of reference meso-scale lattice models. With the correct damage evolution process, the localizing gradient enhancement is shown to capture the size effect phenomenon accurately for a series of geometrically similar concrete beams, using only a single set of material parameters.

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