A 3D mechanistic model for brittle materials containing evolving flaw distributions under dynamic multiaxial loading

Hu, Guangli; Liu, Junwei; Graham‐Brady, Lori; Ramesh, K.T.

doi:10.1016/j.jmps.2015.02.014

Cited by 52 publications

(36 citation statements)

References 78 publications

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“…The flake‐like inclusions also have an indirect effect on the observed strain‐rate sensitivity of the material. Several theoretical studies have shown that the strain rate dependence of the peak (failure) stress of brittle materials is strongly dependent on the characteristics of such defects . The rate dependence was also observed experimentally in many advanced ceramics, including BC …”

Section: Resultsmentioning

confidence: 70%

Anisotropy of Mechanical Properties in a Hot‐Pressed Boron Carbide

Farbaniec

Hogan

McCauley

et al. 2016

Int J Applied Ceramic Tech

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Effects of microstructure and material properties on the mechanical behavior of hot‐pressed boron carbide are presented. The microstructure and intrinsic microstructural inhomogeneities have been characterized using scanning electron microscopy characterization techniques (SEM/EDS/EBSD). In situ mechanical characterizations of the boron carbide microstructure and its larger inhomogeneities have been performed by nanoindentation. Macroscopic dynamic and quasi‐static compressive responses have been studied in two characteristic orientations (parallel and perpendicular to the hot‐pressing direction) using a modified compression Kolsky bar setup (strain rates of 102−103/s) and standard MTS test machine (strain rates of 10−4−10−3/s). The microstructure characterization showed that boron carbide has a fine‐grained microstructure with a complex superposition of nonmetallic inclusions, such as free carbon, AlN, and BN. Nanoindentation tests conducted in three principal planes of the plate revealed an anisotropy of the mechanical properties. The compression tests revealed that the strength of this hot‐pressed boron carbide is orientation dependent. Detailed SEM analysis indicated transgranular fracture and microcracking originating at large carbon inclusions. Influences of microstructural anisotropy on the mechanical response of the material are discussed.

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Section: Resultsmentioning

confidence: 70%

Anisotropy of Mechanical Properties in a Hot‐Pressed Boron Carbide

Farbaniec

Hogan

McCauley

et al. 2016

Int J Applied Ceramic Tech

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“…1,2,17,18 However, there is another type of crack on the wall of the micro-defects and mode-I crack: the mode-II microcracks (parallel to the axial loading in uniaxial loading case), which has not been well considered in concrete models in present literature as mentioned before. [11][12][13][14][15][16][28][29][30][31][32][33][34][35][36] The literature based on experimental observations, atomic simulations and mechanical analysis validated that the real crack is blunt, resulted from the local shear stresses (i.e. sufficient high gradient of stress σ v in Figs 1c & 2a) on the crack wall and surroundings.…”

Section: Why Do the Mode-ii Microcracks Appear?mentioning

confidence: 99%

“…However, this damage behaviour is not well considered in most present literature concerning the irreversible strains in concrete. In detail, initially, the micromechanics method [28][29][30][31][32][33][34][35][36] proposed that the irreversible strains are produced by a series of cracking, which are distinguished as follows: the irreversible opening of mode-I crack due to locking mechanisms of crack faces 28 ; the irreversible sliding-like of mode-II crack (not mode-II microcracks) due to toughness of crack faces 29,30 ; the irreversible-frictional sliding over crack surface 31,32 ; the irreversible cracking of fracture process zone 33,34 ; and other cracking mechanisms. 35,36 Additionally, the macro-mechanics method [11][12][13][14][15][16] generally considered rarely the comprehensive mechanism of concrete damage, because it usually focused on the accurate characterizing of the macroscopic mechanical behaviours.…”

Section: Introductionmentioning

confidence: 99%

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A simple damage model for concrete considering irreversible mode‐II microcracks

Shan

Ouyang

et al. 2016

Fatigue Fract Eng Mat Struct

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A B S T R A C T A simple damage model with the concept of mode-II microcracks on crack wall contributing to the irreversible strains for concrete is developed. By applying the micromechanics method, a microcell-based damage model is introduced to understand the damage behaviour. Further, by introducing the physical interpretation of the damage variable using thermodynamic method, a novel damage variable (irreversible-damage variable) is proposed to describe the irrecoverable strains generated by both mode-II microcracks and irreversible-frictional sliding. With this methodology, a simple continuum damage mechanics model is developed in which both elastic and irreversible damages are considered. As demonstrated by the comparison with experimental results, the proposed model is characterized by accuracy of solutions, sufficiency of physical sense and convenience of implementation. CDM = continuum damage mechanics FPZ = fracture process zone RVE = representative volume element STD = standard deviation SIF = stress intensity factor D = damage variable tensor D e , ω = elastic-damage variable tensor D i = irreversible-damage variable tensor I = four order identity tensor, p i ± = fitting parameters related to damage properties D ± = scalar damage for tensile/compressive uniaxial case D i ± = scalar irreversible-damage for uniaxial tensile/compressive case E = nominal Young's modulus E 0 = initial Young's modulus E = effective Young's modulus E d = degradation of Young's modulus K I = stress intensity factor K IC = critical stress intensity factor 2a = length of crack b = crack opening due to mode-II microcracks b′ = crack opening due to irreversible-frictional sliding da = increment of crack length on crack tip i = number of microcell r = stress ratio α = parameter considering the bia-compressive effects ε 0,δ , ε de,δ , ε di,δ = small additive strain Correspondence: Z. Shan.

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“…As it was first pointed out by Weibull [7], the largest defect plays a critical role in governing the onset of failure. At high strain rates, all the defects contribute to failure [8,9]. These defects are inherent to the material, as a consequence of materials composition and processing conditions, among other things.…”

Section: Introductionmentioning

confidence: 99%

Modeling dynamic fragmentation of concrete under high strain-rate loading

Cereceda

Pavarini

Daphalapurkar

et al. 2016

Proceedings of the 9th International Conference on Fracture Mechanics of Concrete and Concrete Structures

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Extreme high-rate loading conditions in structural materials trigger a complex process of fragmentation involving probabilistic, energetic and mechanical aspects. In this work we discuss a one-dimensional model based on [1] that captures the physics of dynamic fracture and fragmentation in concrete at strain rates from 10 3 to 10 5 /s, with particular interest in the higher strain rate values. In particular, the model considers a one-dimensional bar under a uniform tensile initial strain rate, with a stochastically varying strength. Initial results for the relationship between average fragment size and strain rate show good agreement with shock tube experiments on concrete panels. However, the predicted distribution of fragment size exhibits a smaller variance than that observed in the experiments. Future work will evaluate this difference in the results, which could be the result of the one-dimensionality of the model, heterogeneity of strain rate in the shock tube tests, experimental measurement errors, or a combination of all of these. Further investigations to extend the present model to other brittle materials like glass and concrete are also currently under development.

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A 3D mechanistic model for brittle materials containing evolving flaw distributions under dynamic multiaxial loading

Cited by 52 publications

References 78 publications

Anisotropy of Mechanical Properties in a Hot‐Pressed Boron Carbide

Anisotropy of Mechanical Properties in a Hot‐Pressed Boron Carbide

A simple damage model for concrete considering irreversible mode‐II microcracks

Modeling dynamic fragmentation of concrete under high strain-rate loading

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