ESPCI web site
Le séminaire hebdomadaire du laboratoire PMMH a lieu tous les vendredis à 11h, au premier étage Barre Cassan, campus Jussieu (plan).
Stéphane Perrard
Etienne Reyssat
Virgile Thiévenaz
PMMH
BARRE CASSAN
BAT A 1ER ETAGE CASE 18
7 QUAI SAINT BERNARD
75005 PARIS
France
Tel : (33) 1 40 79 45 22
Séminaire PMMH Lucilla de Arcangelis (Univ. of Naples)
Acoustic fluidization and remote earthquake triggering
Lucilla de Arcangelis, Eugenio Lippiello, Massimo Pica Ciamarra
Engineering Department
University of Campania “Luigi Vanvitelli”
Occasionally, a major earthquake can trigger additional events at distances up to 1000 km away. How that happens is a longstanding puzzle since the amplitude of the seismic waves decreases the farther they travel. We address this problem by a numerical approach modelling the seismic fault as a granular medium (the fault gouge) confined between two rough rigid plates. We show that the unexpected weakness of some faults can be attributed to the emergence of acoustic waves that promote failure by reducing the confining pressure, mechanism known as acoustic fluidization. Indeed, the stick-slip dynamics in a granular seismic fault model is strongly affected by perturbations applied at a characteristic frequency, promoting oscillations normal to the fault, which lead to gradual dynamical weakening and failure. Acoustic waves at the same characteristic frequency spontaneously emerge at the onset of failure in the absence of perturbations, supporting the relevance of acoustic fluidization in earthquake triggering. From the micromechanical point of view, particles belonging to the percolating backbone, which sustains the stress, perform synchronized oscillations over elliptic-like trajectories parallel to the fault plane. These oscillations occur at the characteristic frequency of acoustic fluidization. As the applied shear stress increases because of the incoming seismic wave, these oscillations can become perpendicular to the fault plane, opposing the confining pressure and leading to failure. Seismic waves at the characteristic frequency, even if with a very small amplitude, can lead to remote earthquake triggering.
Séminaires (6)
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Séminaire PMMH - Julien Scheibert (LTDS, EC Lyon)
Vendredi 16 mai de 11h00 à 12h00 - Salle réunion PMMH 1
Metainterfaces : how to design a rough contact that obeys a specific friction law ?
Many devices, including touchscreens and robotic hands, involve frictional contacts. Optimizing those devices requires fine control of the interface's friction law. We lack systematic methods to create dry contact interfaces whose frictional behaviour satisfies preset specifications. In this seminar, I will present (…) -
Séminaire PMMH - Julien Scheibert (LTDS, EC Lyon)
Vendredi 16 mai de 11h00 à 12h00 - Salle réunion PMMH 1
Metainterfaces : how to design a rough contact that obeys a specific friction law ?
Many devices, including touchscreens and robotic hands, involve frictional contacts. Optimizing those devices requires fine control of the interface's friction law. We lack systematic methods to create dry contact interfaces whose frictional behaviour satisfies preset specifications. In this seminar, I will present (…) -
Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
REPROGRAMMABLE HARDWARE FOR DATA PROCESSING AT THE EDGE : A NEW COMPUTING PARADIGM BASED ON NEUROMORPHIC SYSTEMS
The brain's ability to perform efficient and fault-tolerant data processing is strongly related with its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to (…) -
Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
REPROGRAMMABLE HARDWARE FOR DATA PROCESSING AT THE EDGE : A NEW COMPUTING PARADIGM BASED ON NEUROMORPHIC SYSTEMS
The brain's ability to perform efficient and fault-tolerant data processing is strongly related with its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to (…) -
Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
Continuum Mechanics of Hydrated Fibre-Reinforced Soft Tissues
Biological tissues can be represented as bi-phasic continua, with a porous solid phase saturated by an interstitial fluid and reinforced by collagen fibers. This lecture will give an overview of the modelling techniques for fibre-reinforced porous composite materials with statistical orientation of the fibers. Both (…) -
Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
Continuum Mechanics of Hydrated Fibre-Reinforced Soft Tissues
Biological tissues can be represented as bi-phasic continua, with a porous solid phase saturated by an interstitial fluid and reinforced by collagen fibers. This lecture will give an overview of the modelling techniques for fibre-reinforced porous composite materials with statistical orientation of the fibers. Both (…)
Instructions générales pour les conférenciers
Le public du séminaire est très hétérogène (rien qu’au PMMH nous travaillons sur des thématiques très diverses, mécanique des fluides, des milieux granulaires, des solides, physique statistique, physique du mouillage, micro-fluidique, biophysique,...) l’objectif est donc de ne pas faire un séminaire trop spécialiste : au moins la première moitié du séminaire à un niveau accessible pour celui qui ne connaît rien sur le sujet.
Le séminaire a lieu à 11h. rendez-vous 15 minutes avant pour installer et tester la projection.
Le séminaire dure environ 45 minutes pour laisser un peu de temps pour discuter à la fin.
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