Modelling fracture process zone width and length for quasi-brittle fracture of rock, concrete and ceramics

2022 ◽  
Vol 259 ◽  
pp. 108158
Author(s):  
Xiaozhi Hu ◽  
Qingbin Li ◽  
Zhimin Wu ◽  
Shutong Yang
Keyword(s):  
Brittle Fracture ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
Zone Width

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

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.

scholarly journals Nonlocal Criteria for Brittle and Quasi-Brittle Fracture of Geomaterials and Rocks

2018 ◽  
Vol 56 ◽  
pp. 02003 ◽  
Author(s):  
Sergey Suknev
Keyword(s):  
Brittle Fracture ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Common Property ◽  
Process Zone ◽  
Material Structure ◽  
Fracture Criteria ◽  
Stress Concentrations ◽  
Stress Criterion ◽  
Nonlocal Criteria

Nonlocal criteria are used for prediction materials and rock mass failure near stress concentrations (pores, faults, openings, excavations). A common property of nonlocal fracture criteria is the introduction of the intrinsic material length characterizing its microstructure, which allows one to describe the size effect in conditions of stress concentration. At the same time the scope of their application is limited to cases of brittle or quasi-brittle fracture with a small fracture process zone. To expand the scope of the criteria for cases of fracture with a developed fracture process zone, it is proposed to abandon the hypothesis of the size of this zone as a material constant, associated only with the material structure. New fracture criteria are proposed, which are the development of the average stress criterion, and point stress criterion, and which contain a complex parameter that characterizes the size of the fracture process zone and accounts not only for the material structure, but also plastic properties of the material, geometry of the sample, and its loading conditions. Expressions are obtained for the critical pressure in the problem of the formation of tensile cracks under compression in the samples of geomaterials with a circular hole. The calculation results are in good agreement with the experimental data on the fracture of drilled gypsum plates.

Energy Dissipation during Quasi-Brittle Fracture Associated with the Crack and the Fracture Process Zone Progression

2015 ◽  
Vol 665 ◽  
pp. 261-264 ◽  
Author(s):  
Jiří Klon ◽  
Václav Veselý
Keyword(s):  
Energy Dissipation ◽  
Brittle Fracture ◽  
Numerical Simulations ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
Crack Advance ◽  
Fracture Test ◽  
Notched Specimen ◽  
Nonlinear Zone

The paper presents an analysis with an attempt to capture the phenomenon of quasi-brittle fracture based on the record of the fracture test on a notched specimen via separation the energy amounts released for the crack advance and dissipated within the volume of the sizeable nonlinear zone at the crack tip – the fracture process zone (FPZ). The described approach is tested on selected data of published experimental campaigns accompanied with own conducted numerical simulations.

Modelling of Energy Dissipation during Fracture of Concrete Notched Beams: Proportion of the Effective Crack and the Fracture Process Zone Consumption

2016 ◽  
Vol 713 ◽  
pp. 309-312 ◽  
Author(s):  
Jiří Klon ◽  
Václav Veselý
Keyword(s):  
Energy Dissipation ◽  
Brittle Fracture ◽  
Numerical Simulations ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
Crack Advance ◽  
Notched Specimens ◽  
Fracture Tests ◽  
Nonlinear Zone

The paper presents an analysis aiming at capturing the phenomenon of quasi-brittle fracture based on the record of the fracture tests on notched specimens. A method of separation of the energy amounts released for the crack advance and that dissipated within the volume of the sizeable nonlinear zone at the crack tip – the fracture process zone– is introduced. The approach is tested on selected data of published experimental campaigns accompanied with own conducted numerical simulations.

Modelling of fracture process zone and related energy dissipation during quasi-brittle fracture

2012 ◽  
pp. 355-365 ◽  
Author(s):  
Vaclav veselý ◽  
Petr Frantík ◽  
Tomáš Pail ◽  
Zbyněk keršner
Keyword(s):  
Energy Dissipation ◽  
Brittle Fracture ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
Related Energy

scholarly journals Mesoscale modelling of size effect on the evolution of fracture process zone in concrete

2021 ◽  
Vol 245 ◽  
pp. 107559 ◽  
Author(s):  
Rongxin Zhou ◽  
Yong Lu ◽  
Li-Ge Wang ◽  
Han-Mei Chen
Keyword(s):  
Size Effect ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
Mesoscale Modelling

Analysis of Energy Balance When Using Cohesive Zone Models to Simulate Fracture Processes

2002 ◽  
Vol 124 (4) ◽  
pp. 440-450 ◽  
Author(s):  
C. Shet ◽  
N. Chandra
Keyword(s):  
Cohesive Energy ◽  
Cohesive Zone ◽  
Strain Energy ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
Elastic Strain Energy ◽  
Inelastic Strain ◽  
External Work ◽  
Cohesive Zone Models

Cohesive Zone Models (CZMs) are being increasingly used to simulate fracture and fragmentation processes in metallic, polymeric, and ceramic materials and their composites. Instead of an infinitely sharp crack envisaged in fracture mechanics, CZM presupposes the presence of a fracture process zone where the energy is transferred from external work both in the forward and the wake regions of the propagating crack. In this paper, we examine how the external work flows as recoverable elastic strain energy, inelastic strain energy, and cohesive energy, the latter encompassing the work of fracture and other energy consuming mechanisms within the fracture process zone. It is clearly shown that the plastic energy in the material surrounding the crack is not accounted in the cohesive energy. Thus cohesive zone energy encompasses all the inelastic energy e.g., energy required for grainbridging, cavitation, internal sliding, surface energy but excludes any form of inelastic strain energy in the bounding material.

Fiber Debonding Along a Crack Front in Paper

1998 ◽  
Vol 539 ◽  
Author(s):  
H. Kettunen ◽  
K. J. Niskanen
Keyword(s):  
Fracture Energy ◽  
Crack Front ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
Bond Properties ◽  
Crack Line ◽  
Pull Out ◽  
Microscopic Damage ◽  
Debonding Process

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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