Investigation of a Specific Magnetic Characterization dedicated to Manufactured Massive Cores

Projet PSPC LowCO2Motion porté par VALEO. Financement BPI France.Magnetic parts are usually composed of a stack of electrical steel laminations to reduce the eddy current losses. However, for cost reasons or for specific applications the magnetic core can be made from massive steel and thus manufactured with adapted processes such as forging. This kind of process may imply anisotropy and severe inhomogeneity of the material properties. Therefore, for accurate design or study of the electromagnetic part, it is necessary to account for the real properties of the material. In that context, most of the standard characterization procedures are not adapted to represent the magnetic flux behavior through a bulk material and applicable for material anisotropy at the same time. The proposed specific characterization procedure aims at considering these both aspects

Procédé et machine de fomation de capsules contenant un fluide

Selon un procédé de fabrication de capsules (16) contenant un fluide, procède par pas aux étapes suivantes; réception de deux pans (11, 12) de film (1) thermoplastique, chaque pan (11, 12) comportant au moins une colonne (14a, 14b, 14c, 14d) de cavités (10) formées; rapprochement des deux pans (11, 12) pour mettre en correspondance les cavités (10) respectives de chaque pan et placage des pans (11, 12) par des paires de barres (301, 302, 303) qui pincent successivement les pans (11, 12) de part et d'autre des paires de colonnes de cavités (10), remplissage de la poche délimitée entre deux paires de barres (301, 302, 303) par le fluide pour remplir les cavités (10); soudure des pans (11, 12) autour des cavités (10) pour former les capsules (16). Machine mettant en œuvre le procédéSelon un procédé de fabrication de capsules (16) contenant un fluide, procède par pas aux étapes suivantes; réception de deux pans (11, 12) de film (1) thermoplastique, chaque pan (11, 12) comportant au moins une colonne (14a, 14b, 14c, 14d) de cavités (10) formées; rapprochement des deux pans (11, 12) pour mettre en correspondance les cavités (10) respectives de chaque pan et placage des pans (11, 12) par des paires de barres (301, 302, 303) qui pincent successivement les pans (11, 12) de part et d'autre des paires de colonnes de cavités (10), remplissage de la poche délimitée entre deux paires de barres (301, 302, 303) par le fluide pour remplir les cavités (10); soudure des pans (11, 12) autour des cavités (10) pour former les capsules (16). Machine mettant en œuvre le procéd

Predictive control for a single-blow cold upsetting using surrogate modeling for a digital twin

In the realm of forging processes, the challenge of real-time process control amid inherent variabilities is prominent. To tackle this challenge, this article introduces a Proper Orthogonal Decomposition (POD)-based surrogate model for a one-blow cold upsetting process in copper billets. This model effectively addresses the issue by accurately forecasting energy setpoints, billet geometry changes, and deformation fields following a single forging operation. It utilizes Bézier curves to parametrically capture billet geometries and employs POD for concise deformation field representation. With a substantial database of 36,000 entries from 60 predictive numerical simulations using FORGE® software, the surrogate model is trained using a multilayer perceptron artificial neural network (MLP ANN) featuring 300 neurons across 3 hidden layers using the Keras API within the TensorFlow framework in Python. Model validation against experimental and numerical data underscores its precision in predicting energy setpoints, geometry changes, and deformation fields. This advancement holds the potential for enhancing real-time process control and optimization, facilitating the development of a digital twin for the process

Enhancing metal-forming predictions with VR-infused digital twin models

This article presents a two-step method to enhance metal-forming predictions by integrating Virtual Reality (VR) into Digital Twin models, focusing on single-blow cold copper upsetting operations. The process begins with developing a real-time predictive surrogate model that considers actual process parameters, acting as a crucial link between conventional numerical simulations and immediate decision-making. Subsequently, the surrogate model is integrated into a realistic VR environment, aligned with the experimental forging setup. The study underscores the need and potential advantages of real-time digital twins in the forging field, emphasizing the bridging capability between numerical simulations and instant decision-making through predictive modeling and immersive virtual environments

Thixoforming of Steel: New Tools Conception to Analyse Thermal Exchanges and Strain Rate Effects

peer reviewedThrough different papers, authors shown that the influence of thermal exchanges was a first order parameter on the semi-solid steel behaviour, and certainly for every semi-solid metallic materials. These thermal exchanges hide other parameters effect like, for example, the strain rate influence. This paper tries to determine the influence of these two parameters by using a new extrusion device on a hydraulic press. This new tools conception annihilated the influence of the decrease of the punch speed before stopping and permitted to have a constant speed during the experiment. This work also deals with the homogeneous flow during thixoforming of steel and shows the importance to couple initial temperature of the slug with punch speed. This paper presents different conditions which permitted to have a homogeneous flow by keeping a low load

Steel Thixoforging: Heat Exchange Impact on the Mechanical and

peer reviewedSteel thixoforging process combines the advantages of performing parts having highly complex shapes and good mechanical properties. These advantages result from the shear thinning flow behaviour of semi-solids due to microstructure changes during the material deformation. Many parameters such as steel grade, raw speed, slug temperature, tool temperature influence the steel thixoforging process. In this work, we are interested in analysing the influence of thermal conditions as well as ram speed on the flow behaviour and the microstructure of the final parts. To do so, thixo-extrusion tests on a high speed hydraulic press were performed on C38 steels using different ram speeds and different temperatures for the tools. The temperature is measured in the die close to the tool-material interface during the whole process. Correlations between the temperature measurements, the flow profile and the microstructure are discussed. Using the Finite Element code Forge2005, these thixo-extrusion tests are simulated. Using an inverse method, some parameters used in the thermal exchange modelling are identified by successive comparisons between calculated and measured temperatures within the die

Chronological constraints on processes leading to large active landslides

Earth and Planetary Science Letters, v. 235, n. 1-2, p. 141-150, 2005. http://dx.doi.org/10.1016/j.epsl.2005.03.012International audienc

Vers une nouvelle méthodologie des enquêtes en santé réalisées à partir d’abonnés au téléphone

International audienc

Roue polaire d'inducteur de machine électrique tournante

WO201809605

Atrophic Gastritis and Autoimmunity: Results from a Prospective, Multicenter Study

Despite a global decrease, gastric cancer (GC) incidence appears to be increasing recently in young, particularly female, patients. The causal mechanism for this “new” type of GC is unknown, but a role for autoimmunity is suggested. A cascade of gastric precancerous lesions, beginning with chronic atrophic gastritis (CAG), precedes GC. To test the possible existence of autoimmunity in patients with CAG, we aimed to analyze the prevalence of several autoantibodies in patients with CAG as compared to control patients. Sera of 355 patients included in our previous prospective, multicenter study were tested for 19 autoantibodies (anti-nuclear antibodies, ANA, anti-parietal cell antibody, APCA, anti-intrinsic factor antibody, AIFA, and 16 myositis-associated antibodies). The results were compared between CAG patients (n = 154), including autoimmune gastritis patients (AIG, n = 45), non-autoimmune gastritis patients (NAIG, n = 109), and control patients (n = 201). ANA positivity was significantly higher in AIG than in NAIG or control patients (46.7%, 29%, and 27%, respectively, p = 0.04). Female gender was positively associated with ANA positivity (OR 0.51 (0.31–0.81), p = 0.005), while age and H. pylori infection status were not. Myositis-associated antibodies were found in 8.9% of AIG, 5.5% of NAIG, and 4.4% of control patients, without significant differences among the groups (p = 0.8). Higher APCA and AIFA positivity was confirmed in AIG, and was not associated with H. pylori infection, age, or gender in the multivariate analysis. ANA antibodies are significantly more prevalent in AIG than in control patients, but the clinical significance of this finding remains to be established. H. pylori infection does not affect autoantibody seropositivity (ANA, APCA, AIFA). The positivity of myositis-associated antibodies is not increased in patients with CAG as compared to control patients. Overall, our results do not support an overrepresentation of common autoantibodies in patients with CAG