12 results on '"Bouchbinder, Eran"'
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2. Recent developments in dynamic fracture: some perspectives.
- Author
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Fineberg, Jay and Bouchbinder, Eran
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FRACTURE mechanics , *EQUATIONS of motion , *TENSILE strength , *DYNAMICAL systems , *SHEAR (Mechanics) - Abstract
We briefly review a number of important recent experimental and theoretical developments in the field of dynamic fracture. Topics include experimental validation of the equations of motion for straight tensile cracks (in both infinite media and strip geometries), validation of a new theoretical description of the near-tip fields of dynamic cracks incorporating weak elastic nonlinearities, a new understanding of dynamic instabilities of tensile cracks in both 2D and 3D, crack front dynamics, and the relation between frictional motion and dynamic shear cracks. Related future research directions are briefly discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
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3. The dynamics of rapid fracture: instabilities, nonlinearities and length scales.
- Author
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Bouchbinder, Eran, Goldman, Tamar, and Fineberg, Jay
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FRACTURE mechanics , *NONLINEAR systems , *LINEAR elastic fracture mechanics , *CRACK propagation (Fracture mechanics) , *MATHEMATICAL singularities , *MECHANICAL models - Abstract
The failure of materials and interfaces is mediated by cracks, almost singular dissipative structures that propagate at velocities approaching the speed of sound. Crack initiation and subsequent propagation—the dynamic process of fracture—couples a wide range of time and length scales. Crack dynamics challenge our understanding of the fundamental physics processes that take place in the extreme conditions within the almost singular region where material failure occurs. Here, we first briefly review the classic approach to dynamic fracture, namely linear elastic fracture mechanics (LEFM), and discuss its successes and limitations. We show how, on the one hand, recent experiments performed on straight cracks propagating in soft brittle materials have quantitatively confirmed the predictions of this theory to an unprecedented degree. On the other hand, these experiments show how LEFM breaks down as the singular region at the tip of a crack is approached. This breakdown naturally leads to a new theoretical framework coined ‘weakly nonlinear fracture mechanics’, where weak elastic nonlinearities are incorporated. The stronger singularity predicted by this theory gives rise to a new and intrinsic length scale, ℓnl. These predictions are verified in detail through direct measurements. We then theoretically and experimentally review how the emergence of ℓnl is linked to a new equation for crack motion, which predicts the existence of a high-speed oscillatory crack instability whose wavelength is determined by ℓnl. We conclude by delineating outstanding challenges in the field. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
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4. Weakly nonlinear fracture mechanics: experiments and theory.
- Author
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Bouchbinder, Eran, Livne, Ariel, and Fineberg, Jay
- Subjects
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FRACTURE mechanics , *DEFORMATIONS (Mechanics) , *ELASTOMERS , *FRACTOGRAPHY , *METAL fractures - Abstract
Material failure occurs at the small scales in the immediate vicinity of the tip of a crack. Due to its generally microscopic size and the typically high crack propagation velocity, direct observation of the dynamic behavior in this highly deformed region has been prohibitively difficult. Here we present direct measurements of the deformation surrounding the tip of dynamic mode I cracks propagating in brittle elastomers at velocities ranging from 0.2 to 0.8 C s. Both the detailed fracture dynamics and fractography of these materials are identical to that of standard brittle amorphous materials such as soda-lime glass. These measurements demonstrate how Linear Elastic Fracture Mechanics (LEFM) breaks down near the tip of a crack. This breakdown is quantitatively described by extending LEFM to the weakly nonlinear regime, by considering nonlinear elastic constitutive laws up to second order in the displacement-gradients. The theory predicts that, at scales within a dynamic lengthscale ℓ nl from the tip of a single crack, significant log r displacements and 1/ r displacement-gradient contributions arise, and provides excellent quantitative agreement with the measured near-tip deformation. As ℓ nl is consistent with lengthscales that appear in crack tip instabilities, this “weakly nonlinear fracture mechanics” framework may serve as a springboard for the development of a comprehensive theory of fracture dynamics. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
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5. Statistical Physics of Fracture Surfaces Morphology.
- Author
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Bouchbinder, Eran, Procaccia, Itamar, and Sela, Shani
- Subjects
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SURFACES (Technology) , *FRACTURE mechanics , *STATISTICAL physics , *SCALING laws (Statistical physics) , *SURFACE roughness , *ANISOTROPY , *CONFORMAL mapping - Abstract
Experiments on fracture surface morphologies offer increasing amounts of data that can be analyzed using methods of statistical physics. One finds scaling exponents associated with correlation and structure functions, indicating a rich phenomenology of anomalous scaling. We argue that traditional models of fracture fail to reproduce this rich phenomenology and new ideas and concepts are called for. We present some recent models that introduce the effects of deviations from homogeneous linear elasticity theory on the morphology of fracture surfaces, successfully reproducing the multiscaling phenomenology at least in 1+1 dimensions. For surfaces in 2+1 dimensions we introduce novel methods of analysis based on projecting the data on the irreducible representations of the SO(2) symmetry group. It appears that this approach organizes effectively the rich scaling properties. We end up proposing new experiments in which the rotational symmetry is not broken, such that the scaling properties should be particularly simple. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
6. A nonlinear symmetry breaking effect in shear cracks
- Author
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Harpaz, Roi and Bouchbinder, Eran
- Subjects
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SYMMETRY breaking , *NONLINEAR mechanics , *SHEAR (Mechanics) , *CRACK propagation (Fracture mechanics) , *DEFORMATIONS (Mechanics) , *FRACTURE mechanics , *SLIDING friction , *ELASTIC constants - Abstract
Abstract: Shear cracks propagation is a basic dynamical process that mediates interfacial failure. We develop a general weakly nonlinear elastic theory of shear cracks and show that these experience tensile-mode crack tip deformation, including possibly opening displacements, in agreement with Stephenson''s prediction. We quantify this nonlinear symmetry breaking effect, under two-dimensional deformation conditions, by an explicit inequality in terms of the first and second order elastic constants in the quasi-static regime and by semi-analytic calculations in the fully dynamic regime. Our general results are applied to various materials. Finally, we discuss related works in the literature and note the potential relevance of elastic nonlinearities for various problem, including frictional sliding. [Copyright &y& Elsevier]
- Published
- 2012
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7. Viscoelastic fracture of biological composites
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Bouchbinder, Eran and Brener, Efim A.
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VISCOELASTICITY , *FRACTURE mechanics , *BIOMEDICAL materials , *COMPOSITE materials , *DENTIN , *FORCE & energy , *QUANTUM perturbations , *ANISOTROPY - Abstract
Abstract: Soft constituent materials endow biological composites, such as bone, dentin and nacre, with viscoelastic properties that may play an important role in their remarkable fracture resistance. In this paper we calculate the scaling properties of the quasi-static energy release rate and the viscoelastic contribution to the fracture energy of various biological composites, using both perturbative and non-perturbative approaches. We consider coarse-grained descriptions of three types of anisotropic structures: (i) liquid-crystal-like composites, (ii) stratified composites, (iii) staggered composites, for different crack orientations. In addition, we briefly discuss the implications of anisotropy for fracture criteria. Our analysis highlights the dominant lengthscales and scaling properties of viscoelastic fracture of biological composites. It may be useful for evaluating crack velocity toughening effects and structure-dissipation relations in these materials. [Copyright &y& Elsevier]
- Published
- 2011
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8. The singularity in weakly nonlinear fracture mechanics
- Author
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Bouchbinder, Eran, Livne, Ariel, and Fineberg, Jay
- Subjects
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FRACTURE mechanics , *NONLINEAR mechanics , *DEFORMATIONS (Mechanics) , *IRREVERSIBLE processes (Thermodynamics) , *DEFORMATIONS of singularities , *ENERGY dissipation , *ELASTICITY , *QUANTITATIVE research - Abstract
Abstract: Material failure by crack propagation essentially involves a concentration of large displacement-gradients near a crack''s tip, even at scales where no irreversible deformation and energy dissipation occurs. This physical situation provides the motivation for a systematic gradient expansion of general nonlinear elastic constitutive laws that goes beyond the first order displacement-gradient expansion that is the basis for linear elastic fracture mechanics (LEFM). A weakly nonlinear fracture mechanics theory was recently developed by considering displacement-gradients up to second order. The theory predicts that, at scales within a dynamic lengthscale from a crack''s tip, significant displacements and displacement-gradient contributions arise. Whereas in LEFM the singularity generates an unbalanced force and must be discarded, we show that this singularity not only exists but is also necessary in the weakly nonlinear theory. The theory generates no spurious forces and is consistent with the notion of the autonomy of the near-tip nonlinear region. The J-integral in the weakly nonlinear theory is also shown to be path-independent, taking the same value as the linear elastic J-integral. Thus, the weakly nonlinear theory retains the key tenets of fracture mechanics, while providing excellent quantitative agreement with measurements near the tip of single propagating cracks. As is consistent with lengthscales that appear in crack tip instabilities, we suggest that this theory may serve as a promising starting point for resolving open questions in fracture dynamics. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
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9. Dynamic Stability of Crack Fronts: Out-Of-Plane Corrugations.
- Author
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Adda-Bedia, Mokhtar, Arias, Rodrigo E., Bouchbinder, Eran, and Katzav, Eytan
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QUANTUM perturbations , *QUANTUM theory , *DYNAMIC stability , *RAYLEIGH waves , *FRACTURE mechanics , *POISSON processes - Abstract
The dynamics and stability of brittle cracks are not yet fully understood. Here we use the Willis- Movchan 3D linear perturbation formalism [J. Mech. Phys. Solids 45, 591 (1997)] to study the out-of-plane stability of planar crack fronts in the framework of linear elastic fracture mechanics. We discuss a minimal scenario in which linearly unstable crack front corrugations might emerge above a critical front propagation speed. We calculate this speed as a function of Poisson's ratio and show that corrugations propagate along the crack front at nearly the Rayleigh wave speed. Finally, we hypothesize about a possible relation between such corrugations and the long-standing problem of crack branching. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
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10. Intrinsic Nonlinear Scale Governs Oscillations in Rapid Fracture.
- Author
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Goldman, Tamar, Harpaz, Roi, Bouchbinder, Eran, and Fineberg, Jay
- Subjects
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OSCILLATIONS , *FLUCTUATIONS (Physics) , *BRITTLE material fracture , *MATERIALS testing , *CROSS section fluctuations (Nuclear physics) , *FRACTURE mechanics - Abstract
When branching is suppressed, rapid cracks undergo a dynamic instability from a straight to an oscillatory path at a critical velocity &ngr;c. In a systematic experimental study using a wide range of different brittle materials, we first show how the opening profiles of straight cracks scale with the size ℓnl of the nonlinear zone surrounding a crack's tip. We then show, for all materials tested, that &ngr;c is both a fixed fraction of the shear speed and, moreover, that the instability wavelength is proportional to ℓnl. These findings directly verify recent theoretical predictions and suggest that the nonlinear zone is not passive, but rather is closely linked to rapid crack instabilities. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
11. Oscillatory and tip-splitting instabilities in 2D dynamic fracture: The roles of intrinsic material length and time scales.
- Author
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Vasudevan, Aditya, Lubomirsky, Yuri, Chen, Chih-Hung, Bouchbinder, Eran, and Karma, Alain
- Subjects
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LINEAR elastic fracture mechanics , *FRACTURE mechanics , *BRITTLE fractures , *MODULATIONAL instability , *HOPF bifurcations , *BRITTLE materials - Abstract
Recent theoretical and computational progress has led to unprecedented understanding of symmetry-breaking instabilities in 2D dynamic fracture. At the heart of this progress resides the identification of two intrinsic, near crack tip length scales — a nonlinear elastic length scale ℓ and a dissipation length scale ξ — that do not exist in Linear Elastic Fracture Mechanics (LEFM), the classical theory of cracks. In particular, it has been shown that at a propagation velocity v of about 90% of the shear wave-speed, cracks in 2D brittle materials undergo an oscillatory instability whose wavelength varies linearly with ℓ , and at larger loading levels (corresponding to yet higher propagation velocities), a tip-splitting instability emerges, both in agreements with experiments. In this paper, using phase-field models of brittle fracture, we demonstrate the following properties of the oscillatory instability: (i) It exists also in the absence of near-tip elastic nonlinearity, i.e. in the limit ℓ → 0 , with a wavelength determined by the dissipation length scale ξ. This result shows that the instability crucially depends on the existence of an intrinsic length scale associated with the breakdown of linear elasticity near crack tips, independently of whether the latter is related to nonlinear elasticity or to dissipation. (ii) It is a supercritical Hopf bifurcation, featuring a vanishing oscillations amplitude at onset. (iii) It is largely independent of the phenomenological forms of the degradation functions assumed in the phase-field framework to describe the cohesive zone, and of the velocity-dependence of the fracture energy Γ (v) that is controlled by the dissipation time scale in the Ginzburg–Landau-type evolution equation for the phase-field. These results substantiate the universal nature of the oscillatory instability in 2D. In addition, we provide evidence indicating that the tip-splitting instability is controlled by the limiting rate of elastic energy transport inside the crack tip region. The latter is sensitive to the wave-speed inside the dissipation zone, which can be systematically varied within the phase-field approach. Finally, we describe in detail the numerical implementation scheme of the employed phase-field fracture approach, allowing its application in a broad range of materials failure problems. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
12. The emergence of crack-like behavior of frictional rupture: Edge singularity and energy balance.
- Author
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Barras, Fabian, Aldam, Michael, Roch, Thibault, Brener, Efim A., Bouchbinder, Eran, and Molinari, Jean-François
- Subjects
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FRACTURE mechanics , *FLUX (Energy) , *EARTHQUAKE engineering , *EDGES (Geometry) - Abstract
• The edge singularity of cracks is approximately valid for rate-and-state faults. • A physics-based procedure to extract the effective fracture energy is developed. • The effective fracture energy is approximately balanced by the edge energy influx. • Yet, important deviations of frictional rupture from ordinary fracture emerge. The failure of frictional interfaces — the process of frictional rupture — is widely assumed to feature crack-like properties, with far-reaching implications for various disciplines, ranging from engineering tribology to earthquake physics. An important condition for the emergence of a crack-like behavior is the existence of stress drops in frictional rupture, whose basic physical origin has been recently elucidated. Here we show that for generic and realistic frictional constitutive relations, and once the necessary conditions for the emergence of an effective crack-like behavior are met, frictional rupture dynamics are approximately described by a crack-like, fracture mechanics energy balance equation. This is achieved by independently calculating the intensity of the crack-like singularity along with its associated elastic energy flux into the rupture edge region, and the frictional dissipation in the edge region. We further show that while the fracture mechanics energy balance equation provides an approximate, yet quantitative, description of frictional rupture dynamics, interesting deviations from the ordinary crack-like framework — associated with non-edge-localized dissipation — exist. Together with the recent results about the emergence of stress drops in frictional rupture, this work offers a comprehensive and basic understanding of why, how and to what extent frictional rupture might be viewed as an ordinary fracture process. Various implications are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
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