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Younes W.,IRT Jules Verne | Giraud E.,LAMPA | Ahmed Z.,LAMPA | Dal Santo P.,LAMPA | Van Der Veen S.,Airbus
MATEC Web of Conferences | Year: 2016

Creep-age-forming of a thick Al-Cu-Li sheet is studied. An industrial stamping press is used to form a double curvature panel at a reduced scale. This forming, which includes several relaxation steps, is modelled using ABAQUS. A material model describing an elasto-viscoplastic behaviour with anisotropy effect has been identified and implemented in ABAQUS using Fortran subroutine. The numerical model is validated by comparing experiments and numerical results in terms of deformed shapes and an improved forming cycle is suggested. © The Authors, published by EDP Sciences, 2016.

Younes W.,IRT Jules Verne | Giraud E.,LAMPA | Fredj M.,LAMPA | Dal Santo P.,LAMPA | Van Der Veen S.,Airbus
AIP Conference Proceedings | Year: 2016

Creep forming of Al-Mg-Li alloy sheets is studied. An instrumented bulging machine is used to form a double curvature panel at a reduced scale. The deformation of the work-sheet is ensured by a 7475 aluminum alloy lost sheet deformed by a gas pressure applied on its upper surface. A numerical model using the ABAQUS software is developed in order to obtain the pressure law and to ensure the forming conditions during the cycle. This model is validated by comparing experiments and numerical results in terms of deformed shape and thickness evolution. © 2016 Author(s).

Ammar A.,LAMPA | Ammar A.,University of Tunis | Chinesta F.,École Centrale Nantes | Heyd R.,University of Orléans
Entropy | Year: 2017

Enhancing thermal conductivity of simple fluids is of major interest in numerous applicative systems. One possibility of enhancing thermal properties consists of dispersing small conductive particles inside. However, in general, aggregation effects occur and then one must address systems composed of dispersed clusters composed of particles as well as the ones related to percolated networks. This papers analyzes the conductivity enhancement of different microstructures scaling from clusters dispersed into a simple matrix to the ones related to percolated networks exhibiting a fractal morphology. © 2016 by the authors.

El Gueder J.,LAMPA | Giraud E.,LAMPA | Zhao N.,LAMPA | Dal Santo P.,LAMPA
AIP Conference Proceedings | Year: 2016

Cold stretching is a forming process meanly used in aeronautic industry to obtain deep drawing parts from thin sheets. It's not very easy to characterize the process using industrial machines, due to production constraints and complexity of their structures. In this study, an instrumented bench is developed to analyse the forming of double curvature panels in 5754H111 Aluminium alloys. A numerical tool using ABAQUS software is developed to predict the behaviour of thin sheets during the stretching process and also to estimate the residual mechanical field in the formed shapes. The bench is calibrated by comparing experiments and numerical results in terms of deformed shape, in-plane strain levels and thickness evolution. © 2016 Author(s).

Nasri M.A.,LAMPA | Aguado J.V.,École Centrale Nantes | Ammar A.,LAMPA | Cueto E.,University of Zaragoza | And 4 more authors.
Key Engineering Materials | Year: 2015

Forming processes usually involve irreversible plastic transformations. The calculation in that case becomes cumbersome when large parts and processes are considered. Recently Model Order Reduction techniques opened new perspectives for an accurate and fast simulation of mechanical systems, however nonlinear history-dependent behaviors remain still today challenging scenarios for the application of these techniques. In this work we are proposing a quite simple non intrusive strategy able to address such behaviors by coupling a separated representation with a POD-based reduced basis within an incremental elastoplastic formulation. © (2015) Trans Tech Publications, Switzerland.

Ramde S.,PCM Inc | Beauquin J.,Total S.A. | Bellett D.,LAMPA | Duret-Thual C.,French Corrosion Institute | And 2 more authors.
Society of Petroleum Engineers - 2014 SPE Artificial Lift Conference - North America | Year: 2014

The All Metal Progressing Cavity Pump (AMPCP) has been widely used in previous years, in particular in Thermal Enhanced Oil Recovery (TEOR) applications and also in cold aggressive conditions. These harsh environments require continuous improvement of the product Run Life. This is achievable if there is a strong link between Product Development Teams and Operations. The AMPCP behavior during its real conditions of operation remains partially unknown as it cannot be fully instrumented and monitored. The influence of high temperature, high pressure, corrosive gas and mechanical loads on the failure, are therefore difficult to establish. In this paper, a methodology is proposed to solve this problem, based on coupled experimental and numerical analysis. The initial aim is to evaluate the pump behavior in its running conditions (pressure, rotation speed) and to consequently predict pump failure due to fatigue and/or corrosion effect. In an attempt to continuously optimize the All Metal PCP technology, the experimental work has been done in partnership referring to fatigue and corrosive test on specific alloys in order to choose the best material for run life improvement in various running conditions. The numerical work is based on a strongly coupled Fluid Structure Interaction (FSI) study. This analysis shows that the fluid influences consequently the stress level in the pump. It shows that the structure influences the fluid behavior too. This means that the classical static approaches generally focused on only the fluid or only on the structure are not suited for PCP. This new approach can be used to determine the optimal design. Once the identified solutions have been implemented, a close Operation follow up through Field Track software will be used to validate this approach and its success, closing the loop of run life improvements.

Chinesta F.,École Centrale Nantes | Magnin M.,École Centrale Nantes | Roux O.,École Centrale Nantes | Ammar A.,LAMPA | Cueto E.,University of Zaragoza
Entropy | Year: 2015

In this work, we begin by considering the qualitative modeling of biological regulatory systems using process hitting, from which we define its probabilistic counterpart by considering the chemical master equation within a kinetic theory framework. The last equation is efficiently solved by considering a separated representation within the proper generalized decomposition framework that allows circumventing the so-called curse of dimensionality. Finally, model parameters can be added as extra-coordinates in order to obtain a parametric solution of the model. © 2015 by the authors.

Younes W.,IRT Jules Verne | Giraud E.,LAMPA | Dal Santo P.,LAMPA
Key Engineering Materials | Year: 2015

Anisotropic behavior at high temperature of an Aluminum-Lithium alloy was studied. Mechanical tests at a temperature of 350°C and a strain rate of 10-2 s-1 were carried out on samples taken at different angles with respect to the rolling direction of the sheet. Two plasticity criteria (HILL48 and HU2005) were identified and implemented in ABAQUS to predict the anisotropic behavior of the alloy for other angles. Results show that: (i) the alloy exhibits an anisotropic behavior at high temperature and some recrystallization occurs during plastic deformation; (ii) the coefficients of anisotropy depend on strain level and (iii) HU2005 criterion allows describing the behavior of the alloy at high temperature. © (2015) Trans Tech Publications, Switzerland.

PubMed | University of Lorraine and LAMPA
Type: Journal Article | Journal: Physical chemistry chemical physics : PCCP | Year: 2016

By irradiating a cylindrical silver target rotated at a high-speed within the range 300-2400 rpm (lateral speed 0.16-1.25 m s

Najjar W.,LAMPA | Najjar W.,University of Arts | Pupin C.,LAMPA | Legrand X.,University of Arts | And 3 more authors.
Journal of Reinforced Plastics and Composites | Year: 2014

During the preforming stage of woven reinforcement, in the first step of the resin transfer moulding process, the phenomenon of friction occurring at the tool-reinforcement interfaces and the reinforcement-reinforcement interfaces is one of the key parameters of the forming process. This behaviour must be correctly taken into account when modelling the process and a better understanding of the contact and friction phenomena occurring during the woven fabric preforming process is necessary for realistic simulation of the preforming process. Although some existing studies concerning friction of reinforcement have been published, the complex frictional behaviour of fabrics is still not completely clear. The experimental characterization of the frictional behaviour of a specific carbon woven reinforcement (G1151) used for aeronautical applications is the aim of this article and three interfaces have been studied (G1151/G1151, G1151/Plexiglas, G1151/aluminium). The Coulomb coefficients of friction occurring during contact between two layers of fabric and between the fabric and other materials have been determined. The effect of the variation of normal pressure and temperature on the frictional behaviour of this reinforcement has also been analysed. Comparisons between several frictional models, described in the literature, are also conducted in associated with these experimental results. This study highlights a significant tribological anisotropy of the G1151 reinforcement and a dependence of the frictional characteristics on the applied pressure and the temperature. © The Author(s) 2014.

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