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Publications associées (28)

3D printed fiber-optic nanomechanical bioprobe

Sandor Kasas, Jiangtao Zhou, Yiping Wang, Yuguang Chen

Ultrasensitive nanomechanical instruments, e.g. atomic force microscopy (AFM), can be used to perform delicate biomechanical measurements and reveal the complex mechanical environment of biological processes. However, these instruments are limited because ...

IOP Publishing Ltd2023

Learning Dynamics of Spring-Mass Models with Physics-Informed Graph Neural Networks

Olga Fink, Vinay Sharma, Manav Manav

We propose a physics-informed message-passing graph neural network (GNN) for learning the dynamics of springmass systems. The proposed method embeds the underlying physics directly into the message-passing scheme of the GNN. We compare the new scheme with ...

Research Publishing2023

Clip connector device and uses thereof

Anastasios Vassilopoulos

A removable clip connection device particularly adapted to bamboo structures is disclosed, as well as assemblies formed with the same and uses thereof. The clip connection features a base (100) located at a first end (10) of the device, said base having a ...

2022

An elastic rod in frictional contact with a rigid cylinder

Pedro Miguel Nunes Pereira de Almeida Reis, Paul Grandgeorge, Tomohiko Sano

We investigate the load transmission along an elastic rod of finite cross-section in contact with a rigid cylinder, as system often referred to as the generalized capstan problem. In the presence of friction, the idealized classic capstan equation predicts ...

PERGAMON-ELSEVIER SCIENCE LTD2022

An Inertial Uni-Axial Interferometer-Based Accelerometer for Harsh Environments

Mark Edward John Butcher, Gerard Aliana Cervera

For high-impact devices, subsequent vibrations have as much influence on the deterioration of the mechanical structure as the impact itself. To mitigate the consequences of both impacts and resulting vibrations, it is crucial to accurately understand the p ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2022

Optical measurement method for mechanical time base characterization

Simon Nessim Henein, Etienne Frédéric Gabriel Thalmann

The recent adoption of silicon components by the mechanical watch industry has triggered the search for new time bases to advantageously replace the traditional balance and hairspring oscillator. In particular, flexure-based oscillators manufactured in sil ...

euspen2021

Numerical Simulation of Unreinforced Masonry Buildings with Timber Diaphragms

Katrin Beyer, Francesco Vanin, Igor Tomic, Ivana Bozulic

Though flexible diaphragms play a role in the seismic behaviour of unreinforced masonry buildings, the effect of the connections between floors and walls is rarely discussed or explicitly modelled when simulating the response of such buildings. These flexi ...

2021

Optical rotating torque sensor with nano newton-meter resolution based on a hanging torsion wire

Simon Nessim Henein, Etienne Frédéric Gabriel Thalmann, Billy Nussbaumer

This article presents a novel torque measuring setup working in the nano newton-meter range. The central novelty is a long (1 meter range) thin (diameter of a few tens of micrometers) metallic wire used instead of the relatively stiff torsion zone of the s ...

euspen2021

Accurate buoyancy and drag force models to predict particle segregation in vibrofluidized beds

Mehrdad Kiani Oshtorjani

The segregation of large intruders in an agitated granular system is of high practical relevance, yet the accurate modeling of the segregation (lift) force is challenging as a general formulation of a granular equivalent of a buoyancy force remains elusive ...

AMER PHYSICAL SOC2021

Tuning stiffness nonlinearty: theory and applications

Simon Nessim Henein, Ilan Vardi, Mohamed Gamal Abdelrahman Ahmed Zanaty

Perfect elasticity is not achievable in real-life situation, so spring stiffness is not perfectly constant. In this paper, we study the effect of modifying non-linear stiffness terms while keeping the nominal stiffness constant. We introduce three methods ...

ASME2020

Design and Thermal-Structural Analyses of Ancillary Components for the Optical Steering Mirror (M4) for the ITER ECH Upper Launcher

Timothy Goodman, René Chavan, Matteo Vagnoni, Avelino Mas Sanchez

Each of the four ITER Electron Cyclotron Heating Upper Launcher (ECHUL) features eight transmission lines (TLs) that are used to inject 170-GHz microwave power into the plasma at a level of up to 1.31 MW (at the TL diamond window) per line. The millimeter ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2020

Flexure Pivot Oscillators for Mechanical Watches

Etienne Frédéric Gabriel Thalmann

It appears that the concerted efforts of the watchmaking industry are leading towards a limit in mechanical watch accuracy. The general consensus in horology is that the time base's quality factor, a dimensionless number that characterizes the oscillator d ...

EPFL2020

Additive manufacturing by template-assisted 3D electrodeposition: Nanocrystalline nickel microsprings and microspring arrays

Johann Michler, Laszlo Pethö, Patrik Schürch

In this work, we demonstrate that template-assisted electrodeposition is a viable route for fabricating fully metallic 3D micro-architectures with tailored properties. Firstly, we show that the process can be controlled with the aid of a 3D time-dependent ...

ELSEVIER2020

Characterization of a radial cylindrical spring using an electromechanical test bench

Yves Perriard, Yoan René Cyrille Civet, Jonathan André Jean-Marie Chavanne, David Moser

The Center for Artificial Muscles of EPFL in Neuchâtel focuses his research on designing a less invasive cardiac assist device based on a dielectric elastomer actuator. The idea is to place a ring around the aorta and activate it to help failing heart pump ...

2019

Design Analysis of a Shape Memory Alloy Bias-Spring Linear Actuator

Yves Perriard, Morgan Almanza, Sean Thomas

This paper aims to adapt the well established Brinson model for the thermoelastic behaviour of the Shape Memory Effect (SME) so as to compare it to a custom shape memory material modelled using an finite element modelling software. In this work, the Brinso ...

IEEE2019

Cylindrical Dielectric Elastomer Actuator for Cardiac Assist Device

Jonathan André Jean-Marie Chavanne

This work has been triggered because of the need for a new way to relieve the heart. Current solutions are based on invasive systems. The main problem of such assistance is infectious risks. State of the art to define an alternative has allowed highlightin ...

EPFL2019

Bipedal walking and push recovery with a stepping strategy based on time-projection control

Auke Ijspeert, Salman Faraji, Seyed Hamed Razavi

In this paper, we present a simple control framework for online push recovery on biped robots with dynamic stepping properties. Owing to relatively heavy legs in our humanoid robot COMAN, we use a linear model called 3LP, which is composed of three pendulu ...

SAGE PUBLICATIONS LTD2019

Gravity-Insensitive Flexure Pivot Oscillators

Simon Nessim Henein, Ilan Vardi, Etienne Frédéric Gabriel Thalmann, Lennart Rubbert, Mohammad Hussein Kahrobaiyan

Classical mechanical watch plain bearing pivots have frictional losses limiting the quality factor of the hairspring-balance wheel oscillator. Replacement by flexure pivots leads to a drastic reduction in friction and an order of magnitude increase in qual ...

2018

Flexure-Pivot Oscillator Restoring Torque Nonlinearity and Isochronism Defect

Simon Nessim Henein, Etienne Frédéric Gabriel Thalmann, Mohammad Hussein Kahrobaiyan

Flexure pivot based oscillators can advantageously replace the hairspring and balance wheel, the time base used in mechanical watches, by drastically reducing friction. However, flexure pivots have drawbacks including gravity sensitivity and restoring torq ...

AMER SOC MECHANICAL ENGINEERS2018

Theory and design of spherical oscillator mechanisms

Simon Nessim Henein, Roland Andreas Bitterli, Ilan Vardi, Lennart Rubbert, Mohammad Hussein Kahrobaiyan, Nicolas Ferrier, Billy Nussbaumer

In previous work, we showed that two degree of freedom oscillators can be advantageously applied to horological time bases since they can be used to eliminate the escapement mechanism. We subsequently examined planar two degree of freedom oscillators based ...

2018