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Dive into the research topics where David Simon Kammer is active.

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Featured researches published by David Simon Kammer.


Tribology Letters | 2012

On the Propagation of Slip Fronts at Frictional Interfaces

David Simon Kammer; Vladislav Yastrebov; Peter Spijker; Jean-François Molinari

The dynamic initiation of sliding at planar interfaces between deformable and rigid solids is studied with particular focus on the speed of the slip front. Recent experimental results showed a close relation between this speed and the local ratio of shear to normal stress measured before slip occurs (static stress ratio). Using a two-dimensional finite element model, we demonstrate, however, that fronts propagating in different directions do not have the same dynamics under similar stress conditions. A lack of correlation is also observed between accelerating and decelerating slip fronts. These effects cannot be entirely associated with static local stresses but call for a dynamic description. Considering a dynamic stress ratio (measured in front of the slip tip) instead of a static one reduces the above-mentioned inconsistencies. However, the effects of the direction and acceleration are still present. To overcome this, we propose an energetic criterion that uniquely associates, independently on the direction of propagation and its acceleration, the slip front velocity with the relative rise of the energy density at the slip tip.


Tribology Letters | 2015

Linear elastic fracture mechanics predicts the propagation distance of frictional slip

David Simon Kammer; Mathilde Radiguet; Jean-Paul Ampuero; Jean-François Molinari

AbstractWhen a frictional interface is subject to a localized shear load, it is often (experimentally) observed that local slip events propagate until they arrest naturally before reaching the edge of the interface. We develop a theoretical model based on linear elastic fracture mechanics to describe the propagation of such precursory slip. The model’s prediction of precursor lengths as a function of external load is in good quantitative agreement with laboratory experiments as well as with dynamic simulations, and provides thereby evidence to recognize frictional slip as a fracture phenomenon. We show that predicted precursor lengths depend, within given uncertainty ranges, mainly on the kinetic friction coefficient, and only weakly on other interface and material parameters. By simplifying the fracture mechanics model, we also reveal sources for the observed nonlinearity in the growth of precursor lengths as a function of the applied force. The discrete nature of precursors as well as the shear tractions caused by frustrated Poisson’s expansion is found to be the dominant factors. Finally, we apply our model to a different, symmetric setup and provide a prediction of the propagation distance of frictional slip for future experiments.


Proceedings of the National Academy of Sciences of the United States of America | 2016

Properties of the shear stress peak radiated ahead of rapidly accelerating rupture fronts that mediate frictional slip

Ilya Svetlizky; Daniel Pino Muñoz; Mathilde Radiguet; David Simon Kammer; Jean-François Molinari; Jay Fineberg

Significance The transition from stick to slip is governed by rupture fronts propagating along a frictional interface. It has long been suggested that rapid acceleration of these ruptures generates a shear stress peak that propagates ahead of the front. These peaked waves are strong; they can reach amplitudes that are large enough to trigger secondary supershear ruptures. We provide the first extensive quantitative experimental study to our knowledge of these highly directed waves and their relation to the rupture fronts driving them. Combining our experiments with finite-element simulations, we observe how these waves scale. This study provides insight into how rupture fronts accelerate beyond the shear-wave speed and may offer a possibility to obtain illusive information about propagating earthquakes. We study rapidly accelerating rupture fronts at the onset of frictional motion by performing high-temporal-resolution measurements of both the real contact area and the strain fields surrounding the propagating rupture tip. We observe large-amplitude and localized shear stress peaks that precede rupture fronts and propagate at the shear-wave speed. These localized stress waves, which retain a well-defined form, are initiated during the rapid rupture acceleration phase. They transport considerable energy and are capable of nucleating a secondary supershear rupture. The amplitude of these localized waves roughly scales with the dynamic stress drop and does not decrease as long as the rupture front driving it continues to propagate. Only upon rupture arrest does decay initiate, although the stress wave both continues to propagate and retains its characteristic form. These experimental results are qualitatively described by a self-similar model: a simplified analytical solution of a suddenly expanding shear crack. Quantitative agreement with experiment is provided by realistic finite-element simulations that demonstrate that the radiated stress waves are strongly focused in the direction of the rupture front propagation and describe both their amplitude growth and spatial scaling. Our results demonstrate the extensive applicability of brittle fracture theory to fundamental understanding of friction. Implications for earthquake dynamics are discussed.


International Journal of Fracture | 2014

A study of frictional contact in dynamic fracture along bimaterial interfaces

Fabian Barras; David Simon Kammer; Philippe H. Geubelle; Jean-François Molinari

We investigate numerically the dynamic in-plane propagation of a centered crack along bimaterial interfaces using a spectral formulation of the elastodynamic boundary integral equations. Particular attention is given to the effect of contact zones at the subsonic/intersonic transition. In a single set-up, we simulate and describe the different phenomenon observed experimentally (distinct natures of contact zones, unfavorable velocity range, asymmetric crack propagation). We show that different behaviors are observed as function of the crack propagation direction, i.e., with respect to the particle displacements of the compliant material. When the crack propagates in the same direction, the propagation velocities between


Journal of The Mechanics and Physics of Solids | 2014

The existence of a critical length scale in regularised friction

David Simon Kammer; Vladislav Yastrebov; Guillaume Anciaux; Jean-François Molinari


Journal of Geophysical Research | 2017

Off‐fault heterogeneities promote supershear transition of dynamic mode II cracks

Gabriele Albertini; David Simon Kammer

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Science Advances | 2018

The equation of motion for supershear frictional rupture fronts

David Simon Kammer; Ilya Svetlizky; Gil Cohen; Jay Fineberg


Archive | 2014

Slip Fronts at Frictional Interfaces

David Simon Kammer

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Physical Review Letters | 2013

Survival of Heterogeneous Stress Distributions Created by Precursory Slip at Frictional Interfaces

Mathilde Radiguet; David Simon Kammer; Philippe Gillet; Jean-François Molinari


Mechanics of Materials | 2015

The role of viscoelasticity on heterogeneous stress fields at frictional interfaces

Mathilde Radiguet; David Simon Kammer; Jean-François Molinari

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Jean-François Molinari

École Polytechnique Fédérale de Lausanne

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Ilya Svetlizky

Hebrew University of Jerusalem

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Jay Fineberg

Hebrew University of Jerusalem

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Fabian Barras

École Polytechnique Fédérale de Lausanne

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Guillaume Anciaux

École Polytechnique Fédérale de Lausanne

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Jean-Paul Ampuero

California Institute of Technology

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