Time filter

Source Type

Paris, France

Arts et Métiers ParisTech is a French engineering and research graduate school , in the equivalent of the French ivy league. It is a general engineering school recognized for leading French higher education in the fields of mechanics and industrialization. Founded in 1780, it is among the oldest French institutions and it remains one of the most prestigious and selective engineering schools in France.The school has trained 85,000 engineers since its foundation by the Duke of La Rochefoucauld-Liancourt. It is a "Public Scientific, Cultural and Professional Institution" under the authority of the Ministry of Higher Education and Research and has the special status of Grand établissement. Formerly named École nationale supérieure d'arts et métiers , it was a founding member of ParisTech , héSam and France AEROTECH.Arts et Métiers ParisTech consists of eight Teaching and Research Centres and three institutes spread across the country. Its students are called Gadz'Arts.The school, renowned for both its national and international cooperation programmes, has partnerships with many universities and higher-education institutions all around the world. Wikipedia.

Mareau C.,Arts et Metiers ParisTech | Berbenni S.,CNRS Study of Microstructures, Mechanics and Material Sciences lab
International Journal of Plasticity | Year: 2015

The modeling of heterogeneous materials with an elasto-viscoplastic behavior is generally complex because of the differential nature of the local constitutive law. Indeed, the resolution of the heterogeneous problem involves space-time couplings which are generally difficult to estimate. In the present paper, a new homogenization model based on an affine linearization of the viscoplastic flow rule is proposed. First, the heterogeneous problem is written in the form of an integral equation. The purely thermoelastic and purely viscoplastic heterogeneous problems are solved independently using the self-consistent approximation. Using translated field techniques, the solutions of the above problems are combined to obtain the final self-consistent formulation. Then, some applications concerning twophase fiber-reinforced composites and polycrystalline materials are presented. When compared to the reference solutions obtained from a FFT spectral method, a good description of the overall response of heterogeneous materials is obtained with the proposed model even when the viscoplastic flow rule is highly non-linear. Thanks to this approach, which is entirely formulated in the real-time space, the present model can be used for studying the response of heterogeneous materials submitted to complex thermo-mechanical loading paths with a good numerical efficiency. © 2014 Elsevier Ltd. All rights reserved. Source

Favier V.,Arts et Metiers ParisTech | Atkinson H.V.,University of Leicester
Acta Materialia | Year: 2011

Semi-solid processing is used commercially to produce a variety of components and it is therefore important to be able to model the die fill. Micromechanical modelling is one approach to this. Here we compare the micromechanical predictions for the load vs. displacement, in tests where a cylindrical billet is rapidly compressed, with previous experimental findings for an A356 aluminium alloy. Purely viscoplastic modelling is shown to be inadequate. We propose a new model that clearly associates the elastic-type response with the saturated solid skeleton. This gives much more accurate prediction of the initial peak and of the form of the curve as the skeleton breaks down under load. In agreement with experiment, the model predicts the time for the solid skeleton breakdown and that the peak load increases with increasing ram speed and with decreasing fraction liquid. © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Source

Lerat A.,Arts et Metiers ParisTech
Journal of Computational Physics | Year: 2013

Exact expressions of steady discrete shocks are found for a class of dissipative compact schemes approximating a one-dimensional nonlinear hyperbolic problem with a 3rd, 5th and 7th order of accuracy. A discrete solution is given explicitly for the inviscid Bürgers equation and the oscillatory nature of the shock profiles is determined according to the scheme order and to the shock location with respect to the mesh. © 2013 Elsevier Inc. Source

Pierron F.,Arts et Metiers ParisTech
Journal of Strain Analysis for Engineering Design | Year: 2010

This exploratory paper presents some preliminary results on the use of full-field deformation measurements on low-density polymeric foams to identify the evolution of Poisson's ratio with compressive strain. Two types of foams were tested: a standard low-density polyurethane foam and an auxetic foam manufactured from a similar precursor. Two-dimensional digital image correlation was used to measure the strain field at the specimens' surfaces. Then, Poisson's ratios were identified using a dedicated inverse method called the virtual fields method (VFM) and the results compared with the standard approaches. The results illustrate the advantages of the VFM compared to the standard procedure. It was also found that for the standard foam, very strong localization effects resulted in biased Poisson's ratio evaluation. It was shown that this could be corrected by taking into account these localization effects thanks to the full-field information. Source

Allena R.,Arts et Metiers ParisTech
Bulletin of Mathematical Biology | Year: 2013

Cell migration triggered by pseudopodia (or "false feet") is the most used method of locomotion. A 3D finite element model of a cell migrating over a 2D substrate is proposed, with a particular focus on the mechanical aspects of the biological phenomenon. The decomposition of the deformation gradient is used to reproduce the cyclic phases of protrusion and contraction of the cell, which are tightly synchronized with the adhesion forces at the back and at the front of the cell, respectively. First, a steady active deformation is considered to show the ability of the cell to simultaneously initiate multiple pseudopodia. Here, randomness is considered as a key aspect, which controls both the direction and the amplitude of the false feet. Second, the migration process is described through two different strategies: the temporal and the spatial sensing models. In the temporal model, the cell "sniffs" the surroundings by extending several pseudopodia and only the one that receives a positive input will become the new leading edge, while the others retract. In the spatial model instead, the cell senses the external sources at different spots of the membrane and only protrudes one pseudopod in the direction of the most attractive one. © 2013 Society for Mathematical Biology. Source

Discover hidden collaborations