A numerical study on crack branching in quasi-brittle materials with a new effective rate-dependent nonlocal damage model

Pereira, L.F. Magalhaes; Weerheijm, J.; Sluys, L.J.

doi:10.1016/j.engfracmech.2017.06.019

Cited by 44 publications

(15 citation statements)

References 68 publications

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“…The model developed in [13] is briefly presented in this section. This model adapts a damage delay algorithm originally developed for laminated composites [17] in a local damage framework recently modified for the dynamic assessment of concrete [3,18]. Implementation of the model starts from the classical formulation for isotropic damage in eq.…”

Section: The Adobe Delta Damage Modelmentioning

confidence: 99%

Dynamic simulations of traditional masonry materials at different loading rates using an enriched damage delay: Theory and practical applications

Piani

Weerheijm

Sluys

2019

Engineering Fracture Mechanics

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A local damage model has been recently developed for the numerical simulation of the static behaviour of adobe bricks. Mesh insensitivity of the local model was obtained by generalizing the damage delay concept based on a Dirichlet boundary condition decomposition integrated in an implicit solver. The regularization properties of the model were proven before only in statics. In this study, mesh independence is demonstrated in dynamics analysing the problem of a cantilever bar uniaxially loaded at high deformation rates. Furthermore, the physical background of the delay formulation is interpreted regarding the main failure processes in compression exhibited by quasi brittle materials used in masonry. Two limitations of the model in correctly simulating the dynamic behaviour of masonry bricks have been observed. Corrections to the original damage delay formulation are proposed in this study. These enhance the capability of the model to address also distributed failure of traditional geo-materials and the inherent rate dependence also at high strain rate regimes. The improvements are demonstrated in this paper by means of numerical simulations of both theoretical tests and practical applications. These consist of experimental tests in compression recently performed by the authors at different strain rates, from statics to high velocity impact tests.

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Section: The Adobe Delta Damage Modelmentioning

confidence: 99%

Dynamic simulations of traditional masonry materials at different loading rates using an enriched damage delay: Theory and practical applications

Piani

Weerheijm

Sluys

2019

Engineering Fracture Mechanics

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“…In the second category, the continuum approaches, we find the crack band method 21 , nonlocal integral damage models 22 , nonlocal stress-based damage models 23 , and the more recent class of phase-field models [24][25][26][27][28][29][30] . Phase-field models are undoubtedly the methods that have seen the highest popularity given their overall accuracy and ease of implementation.…”

Section: Introductionmentioning

confidence: 99%

Variable-order fracture mechanics and its application to dynamic fracture

Patnaik

Semperlotti

2021

npj Comput Mater

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This study presents the formulation, the numerical solution, and the validation of a theoretical framework based on the concept of variable-order mechanics and capable of modeling dynamic fracture in brittle and quasi-brittle solids. More specifically, the reformulation of the elastodynamic problem via variable and fractional-order operators enables a unique and extremely powerful approach to model nucleation and propagation of cracks in solids under dynamic loading. The resulting dynamic fracture formulation is fully evolutionary, hence enabling the analysis of complex crack patterns without requiring any a priori assumption on the damage location and the growth path, and without using any algorithm to numerically track the evolving crack surface. The evolutionary nature of the variable-order formalism also prevents the need for additional partial differential equations to predict the evolution of the damage field, hence suggesting a conspicuous reduction in complexity and computational cost. Remarkably, the variable-order formulation is naturally capable of capturing extremely detailed features characteristic of dynamic crack propagation such as crack surface roughening as well as single and multiple branching. The accuracy and robustness of the proposed variable-order formulation are validated by comparing the results of direct numerical simulations with experimental data of typical benchmark problems available in the literature.

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“…During this process, dynamic cracks can propagate as fast as the material shear wave speed [3], leading to crack interactions such as obscuration, coalescence, bridging and bifurcation [4]. Several numerical strategies have been developed in an attempt to simulate the complex phenomena of dynamic crack formation and bifurcation, either through continuum or discrete framework (e.g [5][6][7]). However, the coalescence of dynamic fractures remains a challenging task from a numerical standpoint.…”

Section: Introductionmentioning

confidence: 99%

Ultra-high speed X-ray imaging of dynamic fracturing in cementitious materials under impact

et al. 2021

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In this work the dynamic fracturing of an ultra-high strength cementitious material is probed with in-situ ultra-high speed X-ray phase-contrast diagnostics to investigate the phenomenology of dynamic fracture. Gas gun experiments were conducted on two characteristic samples with two different impact speeds, namely 80 and 190 m/s using the edge-on impact test configuration. The samples were placed within the intense X-ray beam providing an observation field of 12.8 mm in width and 8 mm in height. Thanks to equispaced 16 bunches of short X-ray pulses, the samples were imaged through an indirect detector arrangement using the Shimadzu HPV-X2 camera lens-coupled to a fast scintillator capturing through-thickness measurements with an interframe time of 1.06 µs. The comparison of fragmentation patterns between two samples revealed an important insight into velocity dependant spall formation as well as the effects of crack closure and bridging.

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A numerical study on crack branching in quasi-brittle materials with a new effective rate-dependent nonlocal damage model

Cited by 44 publications

References 68 publications

Dynamic simulations of traditional masonry materials at different loading rates using an enriched damage delay: Theory and practical applications

Dynamic simulations of traditional masonry materials at different loading rates using an enriched damage delay: Theory and practical applications

Variable-order fracture mechanics and its application to dynamic fracture

Ultra-high speed X-ray imaging of dynamic fracturing in cementitious materials under impact

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