Modélisation et simulation numérique de l'emboutissage de tôle gaufrées

Ce papier présente nos travaux dans le cadre d'un projet portant sur la modélisation et la simulation numérique de l'emboutissage des tôles gaufrées. Un modèle de comportement incluant diverses natures d'écrouissage (isotrope et cinématique), diverses sources d'anisotropie et couplé à un endommagement isotrope ductile a été utilisé. Un exemple d'emboutissage complexe de tôle gaufrée est enfin présenté et discuté

Etude et modélisation d'un véhicule doté d'un système de chauffage par parois rayonnantes pour l'étude du confort thermique des passagers

PARIS-MINES ParisTech (751062310) / SudocSudocFranceF

Injection of polyurethane foaming on a porous medium

International audiencePolyurethane (PU) foams are widely used in construction, automotive industry, household appliances and other fields. Their low weight and excellent mechanical and thermal insulation properties result from their internal structure. They are sometimes associated to other components to get new polyurethane composites. Structures made from polyurethane foam with reinforcing spacer fabrics are manufactured in reaction injection molding (RIM) processes.Our study concerns the development of models for the simulation of foaming process in a closed cavity with a porous medium positioned on one of the walls. The main objective is to study the foam/porous medium interaction in injection to establish a flow model for polymer foam in a porous medium. Numerical simulations are made using the Stokes-Brinkman model in which a permeability tensor characterizes the porous medium. Reaction kinetic model, density model and viscosity model already developed in a previous work [5] are adapted in order to well describe the foaming inside a porous medium.The calculations are made on an industrial geometry on which experiments have been carried out [6]. It is a rectangular plate mold injected through its center. The parameters of porous medium correspond to a polyester felt (PET). With these computations, an evaluation of the penetration depth in the felt can be givenLes mousses de polyuréthane (PU) sont largement utilisées dans la construction, l'industrie automobile, les appareils électroménagers et d'autres domaines. Leur faible poids et leurs excellentes propriétés d'isolation mécanique et thermique résultent de leur structure interne. Elles sont parfois associées à d'autres composants pour obtenir de nouveaux composites de polyuréthane. Les structures en mousse de polyuréthane avec des tissus de renforcement sont fabriquées par des procédés de moulage par injection-réaction (RIM).Notre étude porte sur le développement de modèles pour la simulation du processus de moussage dans une cavité fermée avec un milieu poreux positionné sur l'une des parois. L'objectif principal est d'étudier l'interaction mousse/milieu poreux en injection afin d'établir un modèle d'écoulement de mousse polymère en milieu poreux.Des simulations numériques sont réalisées à l'aide du modèle de Stokes-Brinkman dans lequel un tenseur de perméabilité caractérise le milieu poreux. Le modèle de cinétique de réaction, le modèle de densité et le modèle de viscosité déjà développés dans un précédent travail [5] sont adaptés afin de bien décrire le moussage à l'intérieur d'un milieu poreux. Les calculs présentés correspondent à une géométrie industrielle sur laquelle des expériences ont été réalisées [6]. Il s’agit d’une plaque rectangulaire injectée par son centre. Le matériau poreux considéré est un feutre constitué de fibres de polyester (PET). Par ce type de calcul, on peut donner une évaluation de la profondeur de pénétration dans le milieu fibreux

The effect of the geometric parameters of the corrugation shape on the vibration analysis of 3D structured beams

International audienceThis paper deals with the vibration analysis of 3D structured beams with double sinusoidal pattern. The corrugation depends on different parameters such as orientation, amplitude and wave length of the double sinusoid shape. First, a numerical modeling was built using the Finite Element method. Then, experimental tests of bending vibration were conducted on planar and corrugated beams. These data validated our model and proved that the resonant frequencies generally increase due to corrugated shape. A parametric study demonstrated that the optimal values of the corrugation shape can be found to increase the resonant frequencies.

Polyurethane foam injection in a cavity in contact with a porous medium

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Mechanical Behavior of Embossed Aluminium Sheets Subjected to Different Loadings

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Modeling and numerical simulation of AA1050-O embossed sheet metal stamping

International audienceIn this paper, a numerical methodology is presented for the stamping simulation of a embossed sheet. A large strains elastoplastic model based on Hill’s anisotropic plasticity criteria and coupled with damage is presented and identified in the case of AA1050-O flat sheets. Finally the stamping of an industrial part is simulated and validate the proposed methodology

Estimation of Distances within Real and Virtual Dental Models as a Function of Task Complexity

Orthodontists have seen their practices evolve from estimating distances on plaster models to estimating distances on non-immersive virtual models. However, if the estimation of distance using real models can generate errors (compared to the real distance measured using tools), which remains acceptable from a clinical point of view, is this also the case for distance estimation performed on digital models? To answer this question, 50 orthodontists (31 women and 19 men) with an average age of 36 years (σ = 12.84; min = 23; max = 63) participated in an experiment consisting of estimating 3 types of distances (mandibular crowding, inter-canine distance, and inter-molar distance) on 6 dental models, including 3 real and 3 virtual models. Moreover, these models were of three different levels of complexity (easy, medium, and difficult). The results showed that, overall, the distances were overestimated (compared to the distance measured using an instrument) regardless of the situation (estimates on real or virtual models), but this overestimation was greater for the virtual models than for the real models. In addition, the mental load associated with the estimation tasks was considered by practitioners to be greater for the estimation tasks performed virtually compared to the same tasks performed on plaster models. Finally, when the estimation task was more complex, the number of estimation errors decreased in both the real and virtual situations, which could be related to the greater number of therapeutic issues associated with more complex models

Mechanical Behavior of Embossed AA1050-O Sheets Subjected to Tension and Forming

International audienceIn this paper, experimental characterization of embossed aluminum sheets is performed using extensive mechanical tests. Rotary embossing is performed on these sheets in order to obtain a periodic hill-and-valley structure. The experimental program consists of realizing mechanical tests such as tension, deep drawing, and hydraulic bulge tests using embossed samples in order to build a database that can be used for future finite element modeling tasks. The tensile tests are performed using digital images correlation (DIC) for total displacement measurements and for detailed strain maps. The hydraulic bulge and deep drawing tests are conducted on embossed circular samples to study their formability. A comparison was made with the plane (non-embossed) sheets to explain the contribution of the embossed structure either in both cases of uniaxial and multiaxial loadings