Micromechanical Model and Associated Validation for Dynamic Failure of Brittle Materials Containing Pores and Slit-Like Flaws

Graham‐Brady, Lori; Katcoff, Cynthia Zingale; Mayercsik, Nathan P.; Kurtis, Kimberly E.

doi:10.1061/(asce)em.1943-7889.0000927

Cited by 3 publications

(10 citation statements)

References 25 publications

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“…One of the most important challenges for employing the self-consistent scheme is determination of local stress field acting on the elliptical inclusion containing micro-cracks. In this paper, the method introduced by Graham-Brady et al (2015) was implemented in this paper to calculate the local stress field [13]. It is noteworthy that another method proposed early by Paliwall and Ramesh (2008), complex method, can be implemented to determine the local stress fields around isolated micro-cracks [6].…”

Section: Theory and Backgroundmentioning

confidence: 99%

“…It is noteworthy that another method proposed early by Paliwall and Ramesh (2008), complex method, can be implemented to determine the local stress fields around isolated micro-cracks [6]. To calculate the local stress field acting on the elliptical inclusion containing the individual micro-crack, the method proposed by Graham-Brady et al (2015) is used as following [13]:…”

Section: Theory and Backgroundmentioning

confidence: 99%

“…Where [ ] is the 3 × 3 identity tensor, [ ] and [ ] are undamaged stiffnesstensor for material in the ellipsoidal inclusion and stiffnesstensor for the damaged matrix material respectively and they are determined as follows [13]:…”

Section: Theory and Backgroundmentioning

confidence: 99%

“…Where [ ] is the Eshelby tensor for the problem of an ellipsoidal inclusion in a matrix, defined as [13]: As illustrated in Figure 2, the major axis of the ellipsoidal inclusion is directed parallel to the global applied loading. The other two axes are perpendicular to the major axis.…”

Section: Theory and Backgroundmentioning

confidence: 99%

“…Although Hu et al (2015) proposed a plastic-damage model based on the self-consistent homogenization scheme, matrix plastic strain due to dislocation in crystalline network is only considered in this model and material degradation and inelastic deformation are more popularly characterized separately [12]. The effective homogenized properties of cracked materials are obtained by following an up-scaling method based on the Eshelby inhomogeneous inclusion solution [13]. Ayyagari et al(2018) proposed a three-dimensional generalized anisotropic constitutive model for brittle solids contain of the spatial evolution of planar wing-cracks subjected to dynamic compressive loading [14].…”

Section: Introductionmentioning

confidence: 99%

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Rock Failure Analysis under Dynamic Loading Based on a Micromechanical Damage Model

Ahmadi

Molladavoodi

2018

Civ Eng J

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A micromechanical constitutive damage model accounting for micro-crack interactions was developed for brittle failure of rock materials under compressive dynamic loading. The proposed model incorporates pre-existing flaws and microcracks that have same size with specific orientation. Frictional sliding on micro-cracks leading to inelastic deformation is very influential mechanism resulting in damage occurrence due to nucleation of wing-crack from both sides of pre-existing micro-cracks. Several homogenization schemes including dilute, Mori-Tanaka, self-consistence, Ponte-Castandea & Willis are usually implemented for up-scaling of micro-cracks interactions. In this study the Self-Consistent homogenization Scheme (SCS) was used in the developed damage model in which each micro-crack inside the elliptical inclusion surrounded by homogenized matrix experiences a stress field different from that acts on isolated cracks. Therefore, the difference between global stresses acting on rock material and local stresses experienced by micro-crack inside inclusion yields stress intensity factor (SIF) at the cracks tips which are utilized in the formulation of the dynamic crack growth criterion. Also the damage parameter was defined in term of crack density parameter. The developed model was programmed and used as a separate and new constitutive model in the commercial finite difference software (FLAC). The dynamic uniaxial compressive strength test of a brittle rock was simulated numerically and the simulated stress-strain curves under different imposed strain rates were compared each other. The analysis results show a very good strain rate dependency especially in peak and post-elastic region. The proposed model predicts a macroscopic stress-strain relation and a peak stress (compressive strength) with an associated transition strain rate beyond which the compressive strength of the material becomes highly strain rate sensitive. Also the damage growth process was studied by using the proposed micromechanical damage model and scale law was plotted to distinguish the dynamic and quasi-dynamic loading boundary. Results also show that as the applied strain rate increases, the simulated peak strength increases and the damage evolution becomes slower with strain increment.

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Section: Theory and Backgroundmentioning

confidence: 99%

Section: Theory and Backgroundmentioning

confidence: 99%

Section: Theory and Backgroundmentioning

confidence: 99%

Section: Theory and Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Rock Failure Analysis under Dynamic Loading Based on a Micromechanical Damage Model

Ahmadi

Molladavoodi

2018

Civ Eng J

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Analysis of Portland cement mortar under impact: A combined material characterization, micromechanics modeling, and dynamic testing approach

Mayercsik

Shaeffer

Graham‐Brady

et al. 2015

Cement and Concrete Research

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Revisiting Critical Flaws in Cement-Based Composites

Landis

Gangsa

Flanders

2016

J. Nanomech. Micromech.

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In this work, X-ray microtomographic images were analyzed to quantify the influence of void spaces in small mortar specimens, with a particular focus on the porosity of the interfacial transition zone (ITZ). Specimens were nominally 5-mm-diameter, 4-mm-long cylinders with 0.5-mm-diameter glass bead aggregates. Specimens were scanned via synchrotron-based X-ray microtomography while they were positioned in an in situ loading frame in a split cylinder configuration. Scans of undamaged specimens were evaluated for porosity both in the bulk paste and in the ITZ. Specifically, voids in the paste and porosity in the ITZ were superimposed onto a map of the principal tensile stress in the specimen in an attempt to identify critical flaws and to measure their role in split cylinder strength. Results indicate that a stress intensity factor-type approach can be used to identify critical flaws in cement paste specimens. Similarly, a critical ITZ region can be identified based on local principal stress and local ITZ porosity. In mortar specimens, this critical ITZ region could account for most of the splitting failures that were not accounted for by a critical flaw. However, some specimens exhibited neither a critical flaw nor a critical ITZ region, suggesting prepeak microcracking or some other nonlinear fracture phenomena.

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Micromechanical Model and Associated Validation for Dynamic Failure of Brittle Materials Containing Pores and Slit-Like Flaws

Cited by 3 publications

References 25 publications

Rock Failure Analysis under Dynamic Loading Based on a Micromechanical Damage Model

Rock Failure Analysis under Dynamic Loading Based on a Micromechanical Damage Model

Analysis of Portland cement mortar under impact: A combined material characterization, micromechanics modeling, and dynamic testing approach

Revisiting Critical Flaws in Cement-Based Composites

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