On a common critical state in localized and diffuse failure modes

Zhu, Huaxiang; Nguyen, Hien Nho Gia; Nicot, François; Darve, Félix

doi:10.1016/j.jmps.2016.05.026

Cited by 71 publications

(72 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thanks to the combine use of photoelastic grains and numerical simulations, the overall behavior of granular materials was shown to rely on a limited number of grains organized in mesostructures called force chains . Following the definition as well as the algorithm given in Peters et al, recent results highlighted the importance of these mesoscale structures with respect to the overall mechanical properties of the granular materials . In particular, it has been shown that the strength of a granular material results from its ability to build relatively long force chains and its ability to constantly rearrange existing ones to cope with any change in the boundary conditions.…”

Section: Introductionmentioning

confidence: 74%

“…To detect birth and death of force chains, the notions of lifespan and life expectancy are introduced similarly as in Zhu et al This analysis is not conducted directly on force chains but on groups of three‐chained particles. For a given time t and a given group of three‐chained particles g , the lifespan ℓ s ( t , g ) is defined as

ℓ_{s} false(t, g false) = \frac{t - t_{g}^{birth}}{t - t_{i}}, ℓ_{s} false(t, g false) \in false[0, 1 false],

where t i =0 is the time at which the incremental stress is applied and

t_{g}^{birth}

is the time at which the 3 particles composing g were first identified as chained particles and from which they remain continuously identified as such until the current time t .…”

Section: Micromechanical Analysis Of the Onset And Development Of Insmentioning

confidence: 87%

Section: Micromechanical Analysis Of the Onset And Development Of Insmentioning

confidence: 99%

“…Now commonly used in the literature, the force chain concept provides a relevant mesoscopic scale to account for the macroscopic mechanical behavior of granular materials . In particular, it has been shown that the strength of a granular material results from its ability to build relatively long force chains and to constantly rearrange the existing force chains to cope with any change in the boundary conditions . Details on the algorithm used to identify the chained particles of a sample can be found in Peters et al The definition of a force chain used throughout this manuscript is briefly reviewed: The particles belonging to a force chain have a higher principal stress than the mean particle principal stress. The principal stress direction of chained particles is aligned with the geometrical contact direction (less than 45° deviation). A force chain contains at least 3 contacting particles. …”

Section: Micromechanical Analysis Of the Onset And Development Of Insmentioning

confidence: 99%

See 3 more Smart Citations

Micro‐inertia origin of instabilities in granular materials

Wautier

Bonelli²,

Nicot

2018

Num Anal Meth Geomechanics

Self Cite

View full text Add to dashboard Cite

Summary Within the framework of the second‐order work theory, the onset of instabilities is explored numerically in loose granular materials through three‐dimensional DEM simulations. Stress controlled directional analysis are performed in Rendulic's plane, and a particular attention is paid to transient evolutions at the microscale. Thanks to a micromechanical analysis, the onset and development of transient mechanical instabilities is explored. It is shown that these instabilities result from the unjamming and bending of a few force chains associated with a local burst of kinetic energy. This burst of kinetic energy propagates to the whole sample and provokes a generalized unjamming of force chains. As force chains buckle, a phase transition from a quasi‐static to an inertial regime is observed. At the macroscopic scale, this results in a transient softening and a loss of controllability. After the collapse of existing force chains, the development of plastic strain is eventually stopped as new stable force chains are built.

show abstract

Section: Introductionmentioning

confidence: 74%

ℓ_{s} false(t, g false) = \frac{t - t_{g}^{birth}}{t - t_{i}}, ℓ_{s} false(t, g false) \in false[0, 1 false],

where t i =0 is the time at which the incremental stress is applied and

t_{g}^{birth}

is the time at which the 3 particles composing g were first identified as chained particles and from which they remain continuously identified as such until the current time t .…”

Section: Micromechanical Analysis Of the Onset And Development Of Insmentioning

confidence: 87%

Section: Micromechanical Analysis Of the Onset And Development Of Insmentioning

confidence: 99%

Section: Micromechanical Analysis Of the Onset And Development Of Insmentioning

confidence: 99%

See 2 more Smart Citations

Micro‐inertia origin of instabilities in granular materials

Wautier

Bonelli²,

Nicot

2018

Num Anal Meth Geomechanics

Self Cite

View full text Add to dashboard Cite

show abstract

“…These forces are the main ingredient that governs the kinematics of particles through local laws, which leads to the macroscopic strain. Once grain loops collapse, the force chain will be broken and significant displacements will appear . Therefore, the failure of the sample is triggered by the instability of the grain loops.…”

Section: Introductionmentioning

confidence: 99%

A multiscale approach for investigating the effect of microstructural instability on global failure in granular materials

Zhao

Yin

Hicher

2018

Num Anal Meth Geomechanics

View full text Add to dashboard Cite

Summary This paper aims to develop a multiscale approach that has the ability to characterise the influence of microstructural instabilities on global failures in granular materials. For this purpose, the Chang‐Hicher multiscale constitutive relation has been implemented into a finite element code, and the expression of the second‐order work, as an indicator of the material instability, has been computed at the interparticle contact scale, at the representative element volume scale, and at the boundary value problem scale. At the global scale, the second‐order work can be obtained through the integration of that obtained at interparticle contacts. Hence, it becomes possible to analyse the range of instability from the microstructure to the macrostructure. Drained and undrained triaxial tests were numerically simulated. With this method, it was demonstrated that the grain‐scale origin of the specimen instability was well captured. Additionally, biaxial tests were conducted and the onsets of localised and diffuse failure in granular assemblies were successfully predicted. The transition from diffuse to localised failure was demonstrated at different scales, whereby the coincidence between the direction of local instabilities and the direction of the shear band became evident. The influence of the boundary conditions and of the heterogeneity of the initial porosity on the failure mode of granular materials was also analysed. All these examples demonstrate that the developed multiscale approach can characterise in a satisfactory manner the influence of instability at the inter‐grain contacts upon the global failure of granular assemblies.

show abstract