Fragmentation of rock under dynamic loads

Shockey, D. A.; Curran, D. R.; Seaman, L.; Rosenberg, J. T.; Petersen, C. F.

doi:10.1016/0148-9062(74)91760-4

Cited by 144 publications

(50 citation statements)

References 6 publications

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“…According to fractographic observations on rock fragments, the mechanism of fragmentation involves the following four stages 3 (Shockey et al, 1974): (1) Activation of pre-existing flaws, (2) Propagation of activated cracks, (3) Crack coalescence and branching, and (4) Isolation of fragments leading to fragmentation.…”

Section: Fragmentation Patternsmentioning

confidence: 99%

“…The drop-shatter test consists in impacting spherical solids on a target with different velocities (Cheong et al, 2003;Salman et al, 2004), whereas the double-impact test is the dynamic counterpart of the static diametral compression of spheres between two rigid platens (Chau et al, 2000;Wu et al, 2004). Experiments using non-spherical solids include the fragmentation of cubes (Giacomini et al, 2009), cylinders (Shockey et al, 1974), slabs (Grange et al, 2008), and beams (Riou et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A direct fragmentation method with Weibull function distribution of sizes based on finite- and discrete element simulations

Paluszny

Tang

Nejati

et al. 2016

International Journal of Solids and Structures

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A direct method is proposed to rapidly fragment bodies during impulse-based discrete element method simulations of multiple body interactions. The approach makes use of patterns and size distributions obtained both from experiments, and from numerical models that rigorously compute fragmentation by growing fractures explicitly. Weibull parameters approximate the fragment size distributions as a function of body size and relative contact velocity. Structured domain decomposition is applied on the colliding bodies directly, resulting in a low-cost fragmentation calculation that depends on relative velocity, but which does not require the computation of fracture growth nor explicit element de-bonding, but instead classifies pre-existing mesh elements into the newly fragmented sub-domains. The method is applied to the fragmentation of a single spherical rock fragment, to an irregularly shaped rock fragment, and to the crushing of an array of spherical rock fragments.

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Section: Fragmentation Patternsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A direct fragmentation method with Weibull function distribution of sizes based on finite- and discrete element simulations

Paluszny

Tang

Nejati

et al. 2016

International Journal of Solids and Structures

View full text Add to dashboard Cite

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“…It is based upon a fragmentation analysis (Denoual and Hild 2000). For brittle materials, the analysis of failure depends upon the microstructure in terms of flaw density and failure stress distribution (Shockey et al 1974).…”

Section: Fragmentation Modelmentioning

confidence: 99%

“…Continuum Damage Mechanics will be used to describe crack networks. In the following, it is assumed that the defect population leading to damage and failure is identical when the material is subjected to quasi-static and dynamic loading conditions (Shockey et al 1974;Denoual and Hild 2000). To understand why a crack nucleates, one has to model the interaction of a nucleated crack and other defects that would nucleate.…”

Section: Fragmentation Modelmentioning

confidence: 99%

Dynamic Fragmentation of an Ultrahigh-Strength Concrete during Edge-On Impact Tests

Forquin

Hild

2008

J. Eng. Mech.

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Abstract:To understand and model damage generated during impact by a penetrator of ultra-high strength concrete targets, edge-on impact tests are performed with the so-called Ductal ® concrete, which is unreinforced or reinforced with short fibers. Two edge-on impact configurations are designed with a dynamic confinement system. The first configuration uses aluminum projectiles and allows us to study the dynamic fragmentation that spreads out within the tile without any confined damage close to the impact point. The fragmentation process is composed of numerous oriented millimetric cracks. In the second configuration, steel projectiles are used with a higher impact velocity. Damaged zones are visualized by using an ultra-high speed camera and a sarcophagus configuration designed to prevent the fragments from moving. The post-mortem studies of impacted tiles enable us to observe an intense fragmentation of the targets and confined damage close to the impact point if steel projectiles are used. Simulations are performed with an anisotropic damage model coupled with a concrete plasticity model. Orientation and crack density are compared with postmortem observations.

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“…The dynamic comminution (i.e., fragmentation, pulverization and crushing) of materials is of interest for many practical purposes, such as explosion effects on concrete structures, impact of metals, composites and ceramics, rock blasting and fracturing of gas or oil shale by chemical explosions or electro-hydraulic pulsed arc in a horizontal borehole [1,2,2-5,5-17, [17][18][19][19][20][21][22][23][24][25][26][27][28][29][30][31]. This article deals with the projectile impact onto concrete walls.…”

Section: Introductionmentioning

confidence: 99%

Strain Rate Dependent Microplane Constitutive Model for Comminution of Concrete under Projectile Impact

Kirane¹,

Su²,

Bažant³

2016

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

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Abstract. The pulverization, fracturing and crushing of materials, briefly called comminution, creates numerous cracks which dissipate a large amount of kinetic energy during projectile impact. At high shear strain rates (10/s − 10 6 /s), this causes an apparent large increase of strength, called 'dynamic overstress'. This long debated phenomenon has recently been explained by the theory of release of local kinetic energy of shear strain rate in finite size particles that are about to form. The theory yields the particle size and the additional kinetic energy density that must be dissipated in finite element codes. In previous research, it was dissipated by additional viscosity, in a model partly analogous to turbulence theory. Here it is dissipated by scaling up the material strength. Microplane model M7 is used and its stress-strain boundaries are scaled up by theoretically derived factors proportional to the −4/3 rd power of the effective deviatoric strain rate and to its time derivative. The crack band model with a random tetrahedral mesh is used and all the artificial damping is eliminated from the finite element program. The scaled model M7 is seen to predict the crater shapes and exit velocities of projectiles penetrating concrete walls as closely as the previous models. The choice of the finite strain threshold for element deletion, which can have a big effect, is also studied. It is proposed to use the highest threshold above which a further increase has a negligible effect.

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Fragmentation of rock under dynamic loads

Cited by 144 publications

References 6 publications

A direct fragmentation method with Weibull function distribution of sizes based on finite- and discrete element simulations

A direct fragmentation method with Weibull function distribution of sizes based on finite- and discrete element simulations

Dynamic Fragmentation of an Ultrahigh-Strength Concrete during Edge-On Impact Tests

Strain Rate Dependent Microplane Constitutive Model for Comminution of Concrete under Projectile Impact

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