The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Daniel Nelias - One of the best experts on this subject based on the ideXlab platform.
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Velocity correlated Crack Front and surface marks in single crystalline silicon
Nature Communications, 2018Co-Authors: Lv Zhao, Didier Bardel, Anne Maynadier, Daniel NeliasAbstract:Single crystalline silicon fractures on low-energy cleavage planes such as (111) and (110). The Crack propagation cannot accurately be predicted by linear elastic fracture mechanics since it does not account for small scale and inelastic phenomena such as atomic lattice trapping. Here we show that, under pure bending load, (110) cleavage in silicon single crystal rapidly accelerates to 3700 m/s without Crack path deviation or Crack branching, contrasting previous observations. We highlight that the Crack Front shape involves strong velocity dependence and presents a curvature jump during very high-speed Crack growth. In addition, we observe special marks—a kind of periodic surface undulation—that exclusively arise on the rapid fracture surfaces, and we suggest that they are Front wave traces resulting from an intrinsic local velocity fluctuation. This finding gives insight to the wavy nature of the Crack Front in the absence of material asperity. Single crystal silicon Cracking, a problem in solar cell operation, remains difficult to accurately predict. Here, the authors show that a silicon single crystal surprisingly cleaves without Crack deviation, and that the Crack Front is accompanied by special marks due to local velocity changes.
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velocity correlated Crack Front and surface marks in single crystalline silicon
Nature Communications, 2018Co-Authors: Lv Zhao, Didier Bardel, Anne Maynadier, Daniel NeliasAbstract:Single crystalline silicon fractures on low-energy cleavage planes such as (111) and (110). The Crack propagation cannot accurately be predicted by linear elastic fracture mechanics since it does not account for small scale and inelastic phenomena such as atomic lattice trapping. Here we show that, under pure bending load, (110) cleavage in silicon single crystal rapidly accelerates to 3700 m/s without Crack path deviation or Crack branching, contrasting previous observations. We highlight that the Crack Front shape involves strong velocity dependence and presents a curvature jump during very high-speed Crack growth. In addition, we observe special marks—a kind of periodic surface undulation—that exclusively arise on the rapid fracture surfaces, and we suggest that they are Front wave traces resulting from an intrinsic local velocity fluctuation. This finding gives insight to the wavy nature of the Crack Front in the absence of material asperity.
Anne Maynadier - One of the best experts on this subject based on the ideXlab platform.
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Velocity correlated Crack Front and surface marks in single crystalline silicon
Nature Communications, 2018Co-Authors: Lv Zhao, Didier Bardel, Anne Maynadier, Daniel NeliasAbstract:Single crystalline silicon fractures on low-energy cleavage planes such as (111) and (110). The Crack propagation cannot accurately be predicted by linear elastic fracture mechanics since it does not account for small scale and inelastic phenomena such as atomic lattice trapping. Here we show that, under pure bending load, (110) cleavage in silicon single crystal rapidly accelerates to 3700 m/s without Crack path deviation or Crack branching, contrasting previous observations. We highlight that the Crack Front shape involves strong velocity dependence and presents a curvature jump during very high-speed Crack growth. In addition, we observe special marks—a kind of periodic surface undulation—that exclusively arise on the rapid fracture surfaces, and we suggest that they are Front wave traces resulting from an intrinsic local velocity fluctuation. This finding gives insight to the wavy nature of the Crack Front in the absence of material asperity. Single crystal silicon Cracking, a problem in solar cell operation, remains difficult to accurately predict. Here, the authors show that a silicon single crystal surprisingly cleaves without Crack deviation, and that the Crack Front is accompanied by special marks due to local velocity changes.
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velocity correlated Crack Front and surface marks in single crystalline silicon
Nature Communications, 2018Co-Authors: Lv Zhao, Didier Bardel, Anne Maynadier, Daniel NeliasAbstract:Single crystalline silicon fractures on low-energy cleavage planes such as (111) and (110). The Crack propagation cannot accurately be predicted by linear elastic fracture mechanics since it does not account for small scale and inelastic phenomena such as atomic lattice trapping. Here we show that, under pure bending load, (110) cleavage in silicon single crystal rapidly accelerates to 3700 m/s without Crack path deviation or Crack branching, contrasting previous observations. We highlight that the Crack Front shape involves strong velocity dependence and presents a curvature jump during very high-speed Crack growth. In addition, we observe special marks—a kind of periodic surface undulation—that exclusively arise on the rapid fracture surfaces, and we suggest that they are Front wave traces resulting from an intrinsic local velocity fluctuation. This finding gives insight to the wavy nature of the Crack Front in the absence of material asperity.
James R Rice - One of the best experts on this subject based on the ideXlab platform.
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perturbative simulations of Crack Front waves
Journal of The Mechanics and Physics of Solids, 2000Co-Authors: John W Morrissey, James R RiceAbstract:Abstract Willis and Movchan [Willis, J.R., Movchan, A.B., 1995. Dynamic weight functions for a moving Crack I. Mode I loading. J. Mech. Phys. Solids 43, 319.] devised weight functions for a dynamic mode I fracture, within the singular Crack model, using a first order perturbation of in-plane Crack motion from the 2D results. Ramanathan and Fisher [Ramanathan, S., Fisher, D.S., 1997. Dynamics and instabilities of planar tensile Cracks in heterogeneous media. Phys. Rev. Lettr. 79, 877.] reformulated the Willis-Movchan’s result in terms of Crack growth at constant fracture energy, thereby confirming the existence of a Crack Front wave. Such a wave, as a propagating mode local to the moving Crack Front, was seen in the non-perturbative numerical simulations based on a cohesive zone fracture model, equivalent to growth at constant fracture energy. In this paper, the result of Ramanathan and Fisher, given in the wavenumber–frequency domain, is recast in the wavenumber–time domain to analyze fracture propagation within first-order perturbations for the singular Crack model. This allows application of a spectral numerical methodology and is shown to be consistent with the known 2D results. Through analysis of a single spatial mode of Crack shape, the propagating Crack Front wave and its resonance are demonstrated. Crack propagation through a randomly heterogeneous zone, and growth of disorder with propagation distance, are also examined.
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Crack Front waves
Journal of The Mechanics and Physics of Solids, 1998Co-Authors: John W Morrissey, James R RiceAbstract:We present simulations of 3 D dynamic fracture which suggest that a persistent elastic wave is generated in response to a localized perturbation of a propagating Crack Front, e.g., by a local heterogeneity of critical fracture energy. The wave propagates along the moving Crack Front and spreads, relative to its origin point on the fractured surface, at a speed slightly below the Rayleigh speed. The simulations were done using the spectral elastodynamic methodology of Geubelle and Rice (1995). They model failure by a displacementweakening cohesive model, which corresponds in the singular Crack limit to Crack growth at a critical fracture energy. Confirmation that Crack Front waves with properties like in our simulation do exist has been provided by Ramanathan and Fisher (1997). Through a derivation based on the linearized perturbation analysis of dynamic singular tensile Crack growth by Willis and Movchan (1995), those authors found by numerical evaluation that a transfer function thereby introduced has a simple pole at a certain w/k ratio, corresponding to a non-dispersive wave. Further, we show that as a consequence of these persistent waves, when a Crack grows through a region of small random fluctuations in fracture energy, the variances of both the local propagation velocity and the deformed slope of the Crack Front increase, according to linearized perturbation theory. in direct proportion to distance of growth into the randomly heterogeneous region. That rate of disordering is more rapid than the growth of the variances with the logarithm of distance established by Perrin and Rice (1994) for a model elastodynamic fracture theory based on a scalar wave equation. That scalar case, which shows slowly decaying (as t -“‘) rather than persistent Crack Front waves, is analyzed here too. 0 1998 Elsevier Science Ltd. All rights reserved
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Disordering of a dynamic planar Crack Front in a model elastic medium of randomly variable toughness
Journal of The Mechanics and Physics of Solids, 1994Co-Authors: Gilles Perrin, James R RiceAbstract:Abstract Rice et al . (1994, J. Mech. Phys. Solids 42 , 813–843) analyse the propagation of a planar Crack with a nominally straight Front in a model elastic solid with a single displacement component. Using the form of their results for a strictly linearized perturbation from a straight Crack Front which moves at uniform speed, we give the corresponding first-order expression for the deviation of a Crack Front from straightness as a direct integral expression in the deviation of the material toughness from uniformity in the Crack plane. We then use this expression to analyse the autocorrelation of the Crack Front position when the toughness deviations are random. We find that the root mean square deviation in position diverges logarithmically with travel distance across the random toughness region, as do the variances of the propagation velocity and slope of the Crack Front. That is, according to strictly linearized analysis, perturbed about the solution for a uniformly moving Crack Front, the perturbations from straightness and from uniform propagation speed should grow without bound in the presence of random deviations in toughness. What is remarkable about this result is that, according to the same strictly linearized analysis, if the toughness is completely uniform over the remaining part of the fracture plane, after encounter with a region of nonuniform toughness, the moving Crack Front becomes asymptotically straight with increase of time. Nonlinearities, not considered here, must control how statistically disordered the Crack Front can ultimately become as it propagates through a region of random toughness variation. Also, because of the logarithmic nature of the growth, significant disorder can occur in response to small perturbations only when the Crack moves over a great distance compared to the correlation length scale in the fracture toughness.
Renaud Toussaint - One of the best experts on this subject based on the ideXlab platform.
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SELF-AFFINE SCALING DURING INTERFACIAL Crack Front PROPAGATION
Dynamics of Complex Interconnected Systems: Networks and Bioprocesses, 2020Co-Authors: Stéphane Santucci, Knut Jørgen Måløy, Renaud Toussaint, Jean SchmittbuhlAbstract:We have performed an experimental study of slow Crack Front propagation through a weak plane of a transparent Plexiglas block. Spatial random toughness fluctuations along the weak interface generate a rough Crack line in pinning locally the cr ack Front, and leads to an intermittent dynamics of the Crack Front line. Using a high speed and high resolution camera we are able to capture the features of this complex dynamics. A new analysis procedure is proposed in order to measure the waiting time fluctuations, and study the local burst dynamics and structure along the Crack Front during its propagation. First, we confirm previous results [1]: the fracture Front dynamics is governed by local and irregular avalanches with very large size and velocity fluctuations, a nd can be described in terms of a FamilyVicsek scaling with a roughness exponent �≃ 0.6 and a dynamic exponent �≃ 1.2. Then, focusing in particular on the avalanches structure, we show that the system exhibits self-affi ne scaling with
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local dynamics of a randomly pinned Crack Front during creep and forced propagation an experimental study
Physical Review E, 2011Co-Authors: Ken Tore Tallakstad, Stéphane Santucci, Renaud Toussaint, Jean Schmittbuhl, Knut Jørgen MåløyAbstract:: We have studied the propagation of a Crack Front along the heterogeneous weak plane of a transparent poly(methyl methacrylate) (PMMA) block using two different loading conditions: imposed constant velocity and creep relaxation. We have focused on the intermittent local dynamics of the fracture Front for a wide range of average Crack Front propagation velocities spanning over four decades. We computed the local velocity fluctuations along the fracture Front. Two regimes are emphasized: a depinning regime of high velocity clusters defined as avalanches and a pinning regime of very low-velocity creeping lines. The scaling properties of the avalanches and pinning lines (size and spatial extent) are found to be independent of the loading conditions and of the average Crack Front velocity. The distribution of local fluctuations of the Crack Front velocity are related to the observed avalanche size distribution. Space-time correlations of the local velocities show a simple diffusion growth behavior.
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local waiting time fluctuations along a randomly pinned Crack Front
Physical Review Letters, 2006Co-Authors: Knut Jørgen Måløy, Stéphane Santucci, Jean Schmittbuhl, Renaud ToussaintAbstract:The propagation of an interfacial Crack along a heterogeneous weak plane of a transparent Plexiglas block is followed using a high resolution fast camera. We show that the fracture Front dynamics is governed by local and irregular avalanches with very large size and velocity fluctuations. We characterize the intermittent dynamics observed, i.e., the local pinnings and depinnings of the Crack Front by measuring the local waiting time fluctuations along the Crack Front during its propagation. The deduced local Front line velocity distribution exhibits a power law behavior, Pv / v y with 2:55 0:15, for velocities v larger than the average Front speed hvi. The burst size distribution is also a power law, PS / S y with 1:7 0:1. Above a characteristic length scale of disorder L d 15 m, the avalanche clusters become anisotropic providing an estimate of the roughness exponent of the Crack Front line, H 0:66. The physics community has recently paid a lot of attention to the study of damaging processes [1-3]. This interest is motivated not only by the practical benefits to many engineering domains, but also from a more fundamental point of view, by the diverse challenging questions brought forward, in particular, in statistical physics [4]. The role of heterogeneities during Crack propagation is of central importance since they induce local pinnings of the Crack Front and subsequently trigger a very complex history of the fracture in the material. One of the consequences of this phenomenology is the roughness of fracture surfaces left by the Crack. Indeed, Cracks in heterogeneous media exhibit a self-affine morphology, with long range correlations. The associated roughness exponent was found to be very robust for different materials, over a broad range of length scales [5-11], and was further conjectured to be universal [7,8]. A recent work [2,12] suggests that the origin of these self-affine long range correlations comes from the elastic interactions within the damage zone and proposes a link between the roughness exponent and the critical exponent for the correlation length of the damage clusters. More generally, Front propagation in random media has become a challenging problem related to the dynamics of interfaces in many different physical systems theoretically connected, such as Crack Fronts [11], magnetic domain walls [13], or wetting contact lines [14-16], where elasticity and disorder compete to shape the interface. In order to shed some light on the interactions between the Crack Front and material heterogeneities, a simplification to a two dimensional configuration-an interfacial Crack-has been proposed both experimentally [17,18] and theoretically [12,19]. The interfacial configuration provides a higher resolution since all locations of the Crack Front belong to the same plane. Moreover, using a transparent material and a high resolution fast camera, the detailed complex Crack dynamics can be captured, following the Crack Front with a high precision both in time and space [20]. So far experiments have been focused on the fracture Front line morphology leading to the estimated roughness exponent 0:55 0:03 [17], followed up by a longer study showing 0:63 0:03 [18]. First attempts have been recently performed to analyze the interfacial Crack Front dynamics [20,21]. These studies have shown that the fracture Front propagation is intermittent and can be described in terms of a Family-Vicsek scaling [22] with a roughness 0:6 and a dynamic exponent 1:2 0:2. In this Letter, we study a system first studied experimentally by Schmittbuhl and Maloy [17,20]. Whereas previous studies focused on the morphology of the inter-facial Crack [17], we focus on the local Crack dynamics, and on the distribution in both time and space of the waiting time during pinning events. To address this problem , we introduce a new analysis procedure in order to study the local waiting time fluctuations. The improved experimental techniques and resolution allow us to show that the dynamics of the fracture Front is driven by local irregular avalanches with very large size and velocity fluctuations, and anisotropic shapes whose scaling is directly linked to the self-affine scaling of the Crack Front itself. This new set of experiments also confirms earlier results on such systems [17,20]. We describe here experiments where two Plexiglas plates are annealed together to create a single block with a weak interface [17]. The plates are of dimensions: 32 cm 14 cm 1 cm and 34 cm 12 cm 0:4 cm, and annealed together at 205 C under several bars of normal pressure. Before annealing, both plates are sand-blasted on one side with 50 m steel particles or 100 m glass beads. Sandblasting introduces a random topography which induces local toughness fluctuations during the an-nealing procedure. We have measured the profile of a sandblasted Plexiglas surface, using a white light interfer-ometry technique (performed at SINTEF-Oslo laboratory) and found that the local irregularities have a characteristic PRL 96,
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local waiting time fluctuations along a randomly pinned Crack Front
arXiv: Materials Science, 2005Co-Authors: Knut Jørgen Måløy, Stéphane Santucci, Jean Schmittbuhl, Renaud ToussaintAbstract:The propagation of an interfacial Crack along a heterogeneous weak plane of a transparent Plexiglas block is followed using a high resolution fast camera. We show that the fracture Front dynamics is governed by local and irregular avalanches with very large size and velocity fluctuations. We characterize the intermittent dynamics observed, i.e. the local pinnings and depinnings of the Crack Front which trigger a rich burst activity, by measuring the local waiting time fluctuations along the Crack Front during its propagation. The local Front line velocity distribution deduced from the waiting time analysis exhibits a power law behavior, $P(v) \propto v^{-\eta}$ with $\eta = 2.55 \pm 0.15$, for velocities $v$ larger than the average Front speed $ $. The burst size distribution is also a power law, $P(S)\propto S^{-\gamma}$ with $\gamma=1.7 \pm 0.1$. Above a characteristic length scale of disorder $L_d \sim 15 \mu m$, the avalanche clusters become anisotropic, and the scaling of the anisotropy ratio provides an estimate of the roughness exponent of the Crack Front line, $H=0.66$, in close agreement with previous independent estimates.
Lv Zhao - One of the best experts on this subject based on the ideXlab platform.
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Velocity correlated Crack Front and surface marks in single crystalline silicon
Nature Communications, 2018Co-Authors: Lv Zhao, Didier Bardel, Anne Maynadier, Daniel NeliasAbstract:Single crystalline silicon fractures on low-energy cleavage planes such as (111) and (110). The Crack propagation cannot accurately be predicted by linear elastic fracture mechanics since it does not account for small scale and inelastic phenomena such as atomic lattice trapping. Here we show that, under pure bending load, (110) cleavage in silicon single crystal rapidly accelerates to 3700 m/s without Crack path deviation or Crack branching, contrasting previous observations. We highlight that the Crack Front shape involves strong velocity dependence and presents a curvature jump during very high-speed Crack growth. In addition, we observe special marks—a kind of periodic surface undulation—that exclusively arise on the rapid fracture surfaces, and we suggest that they are Front wave traces resulting from an intrinsic local velocity fluctuation. This finding gives insight to the wavy nature of the Crack Front in the absence of material asperity. Single crystal silicon Cracking, a problem in solar cell operation, remains difficult to accurately predict. Here, the authors show that a silicon single crystal surprisingly cleaves without Crack deviation, and that the Crack Front is accompanied by special marks due to local velocity changes.
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velocity correlated Crack Front and surface marks in single crystalline silicon
Nature Communications, 2018Co-Authors: Lv Zhao, Didier Bardel, Anne Maynadier, Daniel NeliasAbstract:Single crystalline silicon fractures on low-energy cleavage planes such as (111) and (110). The Crack propagation cannot accurately be predicted by linear elastic fracture mechanics since it does not account for small scale and inelastic phenomena such as atomic lattice trapping. Here we show that, under pure bending load, (110) cleavage in silicon single crystal rapidly accelerates to 3700 m/s without Crack path deviation or Crack branching, contrasting previous observations. We highlight that the Crack Front shape involves strong velocity dependence and presents a curvature jump during very high-speed Crack growth. In addition, we observe special marks—a kind of periodic surface undulation—that exclusively arise on the rapid fracture surfaces, and we suggest that they are Front wave traces resulting from an intrinsic local velocity fluctuation. This finding gives insight to the wavy nature of the Crack Front in the absence of material asperity.