CAD-based Calibration of a 3D DIC System

International audienceThe aim of this study is to predict the strains induced by welding-brazing of automotive thin metal sheets using finite elements simulations. In order to validate the simulations, experimental tests on industrial parts are carried out. One goal of these tests is to determine 3D surface displacement fields during welding. The measurement technique chosen for these tests is 3D surface DIC (stereocorrelation). To take into account the specificity of these tests (object size about one square meter) a new calibration method of the stereovision system has been developed. Currently, calibration methods are based on the knowledge of the calibration target geometry and its projections onto both right and left camera frames. In the approach proposed herein, the calibration is performed directly on the measured part, which is modeled by a Bézier patch. A first step consists in finding the best 3D (CAD surface) to 2D (camera picture) transformation

Fabrication additive par modulation de vitesse de balayage

The present invention relates to a method for selective additive manufacturing of a three-dimensional object from a powder layer, the method comprising the steps of: - applying an additive manufacturing powder layer on a support or on a previously consolidated layer, - emitting a laser beam onto a first point of the additive manufacturing powder layer so as to consolidate a first area of the powder layer comprising the first point, the method further comprising - adjusting a scanning speed of the laser beam according to an estimated temperature variation of the powder layer at a second point distinct from the first point of the powder layer caused by the emission of the laser beam, so as to consolidate the first area of the powder layer, - emitting a laser beam onto the second point so as to consolidate a second area of the powder layer comprising the second point, the estimated temperature variation being a function of a predetermined time interval separating the emission on the first point and the emission on the second point, the distance separating the first point and the second point which is equal to the product of the scanning speed adjusted by the predetermined time interval.La présente invention concerne un procédé de fabrication additive sélective d'un objet tridimensionnel à partir d'une couche de poudre, le procédé comprenant les étapes de: -application d'une couche de poudre de fabrication additive sur un support ou sur une couche préalablement consolidée, -émission d'un faisceau laser sur un premier point de la couche de poudre de fabrication additive, de sorte à consolider une première zone de la couche de poudre comprenant le premier point, le procédé comprenant en outre -un ajustement d'une vitesse de balayage du faisceau laser en fonction d'une variation de température estimée de la couche de poudre en un deuxième point distinct du premier point de la couche de poudre causée par l'émission du faisceau laser de sorte à consolider la première zone de la couche de poudre, -une émission d'un faisceau laser sur le deuxième point de sorte à consolider une deuxième zone de la couche de poudre comprenant le deuxième point, la variation de température estimée étant fonction d'un intervalle de temps prédéterminé séparant l'émission sur le premier point et l'émission sur le deuxième point et de la distance séparant le premier point et le deuxième point qui est égale au produit de la vitesse de balayage ajustée par l'intervalle de temps prédéterminé

Trajectoire adaptative pour fabrication additive utilisant une source laser

The invention relates to a method (P) for determining the path followed by a selective additive manufacturing laser beam of a three-dimensional object, the laser beam being intended to be emitted to a layer of powder and moved along a path consisting of a plurality of adjacent paths so as to melt the powder layer, characterised in that the paths are determined by implementing the following steps: a) determining, on a predetermined reference path (Ti), several reference points (Tij), b) determining several adjacent points (Ti+1j) located on the same side of the reference path, each adjacent point (Ti+1j) being associated with a reference point (Tij) and being such that a simulated adjacent melting zone which surrounds the adjacent point (Ti+1j) and a simulated reference melting zone which surrounds the reference point (Tij) have an overlap corresponding to a fraction of a transverse width of the simulated reference melting zone which is between a predetermined minimum fraction and a predetermined maximum fraction, c) determining an adjacent path (Ti+1) passing through the several determined adjacent points, d) iterating steps a) to c) using the determined adjacent path as a new reference path, so as to determine, in each iteration, a new adjacent path, the set of thus determined adjacent paths defining the path intended to be followed by the laser beam, the path being stored and/or transmitted to a control unit of a selective additive manufacturing device.L'invention concerne un procédé (P) de détermination de trajectoire suivie par un faisceau laser de fabrication additive sélective d'un objet tridimensionnel, le faisceau laser étant destiné à être émis vers une couche de poudre et déplacé selon une trajectoire constituée d'une pluralité de chemins adjacents pour provoquer une fusion de la couche de poudre, caractérisé en ce que les chemins sont déterminés en mettant en œuvre les étapes suivantes : a) détermination sur un chemin de référence (Ti) prédéterminé de plusieurs points de référence (Tij), b) détermination de plusieurs points adjacents (Ti+1j) situés d'un même côté du chemin de référence, chaque point adjacent (Ti+1j) étant associé à un point de référence (Tij) et étant tel qu'une zone de fusion adjacente simulée qui entoure ledit point adjacent (Ti+1j) et une zone de fusion de référence simulée qui entoure le point de référence (Tij) ont un chevauchement correspondant à une fraction d'une largeur transversale de la zone de fusion de référence simulée qui est comprise entre une fraction minimale prédéterminée et une fraction maximale prédéterminée, c) détermination d'un chemin adjacent (Ti+1) passant par les plusieurs points adjacents déterminés, d) itération des étapes a) à c) en utilisant le chemin adjacent déterminé comme nouveau chemin de référence, de façon à déterminer à chaque itération un nouveau chemin adjacent, l'ensemble des chemins adjacents ainsi déterminés définissant la trajectoire destinée à être suivie par le faisceau laser, ladite trajectoire étant mémorisée et/ou transmise à une unité de contrôle d'un appareil de fabrication additive sélective

Fabrication additive par modulation de puissance laser

The invention relates to a method for the selective additive manufacturing of a three-dimensional object from a powder layer, the method comprising the steps of: - applying an additive manufacturing powder layer on a support or on a previously consolidated layer, - emitting a laser beam on a first point of the additive manufacturing powder layer so as to consolidate a first area of the powder layer comprising the first point, the method further comprising - adjusting a power of the laser beam as a function of an estimated temperature variation of the powder layer at a second point distinct of the first point of the powder layer, caused by the emission of the laser beam so as to consolidate the first area of the powder layer, the estimated temperature variation being a function of the distance between the first point and the second point and a predetermined time interval, - emitting a laser beam on the second point with the adjusted power so as to consolidate a second area of the powder layer comprising the second point, wherein the emission of the laser beam on the first point and the emission of the laser beam on the second point are temporally separated from the predetermined time interval.L'invention concerne un procédé de fabrication additive sélective d'un objet tridimensionnel à partir d'une couche de poudre, le procédé comprenant les étapes de : - application d'une couche de poudre de fabrication additive sur un support ou sur une couche préalablement consolidée, - émission d'un faisceau laser sur un premier point de la couche de poudre de fabrication additive, de sorte à consolider une première zone de la couche de poudre comprenant le premier point, le procédé comprenant en outre - un ajustement d'une puissance du faisceau laser en fonction d'une variation de température estimée de la couche de poudre en un deuxième point distinct du premier point de la couche de poudre causée par l'émission du faisceau laser de sorte à consolider la première zone de la couche de poudre, la variation de température estimée étant fonction de la distance entre le premier point et le deuxième point et d'un intervalle de temps prédéterminé, - une émission d'un faisceau laser sur le deuxième point avec la puissance ajustée de sorte à consolider une deuxième zone de la couche de poudre comprenant le deuxième point, l'émission du faisceau laser sur le premier point et l'émission du faisceau laser sur le deuxième point étant temporellement séparées de l'intervalle de temps prédéterminé

Management and monitoring of patients treated with zonisamide: the OZONE study.

International audienceTo characterise patients treated with zonisamide in everyday practice and describe the effectiveness and tolerability of treatment. This was an observational, longitudinal, naturalistic study, conducted by neurologists in France. Patients who had started zonisamide treatment at least three months prior to inclusion were eligible. Data were collected at routine consultations at inclusion (Visit 1) and three to six months later (Visit 2). At Visit 1, investigators documented epilepsy-related variables based on patient records before initiation of zonisamide and at inclusion. At Visit 2, the investigators re-evaluated seizure activity and rated effectiveness. Adverse events were also documented. A total of 428 patients were included in the study based on evaluation by 132 neurologists. Zonisamide was initiated at a daily dose of 50 mg and 25 mg in 61% and 31.8% of patients, respectively. The median maintenance dose was 300 mg/day. Prior to initiation of zonisamide, the mean seizure frequency was 16.0 seizures/month. This was reduced to 8.7 seizures/month at Visit 1 and to 7.1 seizures/month at Visit 2. The response rate and proportion of seizure-free patients was 61.9 and 31.1% at Visit 1 and 65.9 and 25.6% at Visit 2, respectively. The frequency of seizures at Visit 2 decreased significantly (p60% for all analysed subgroups. The proportion of seizure-free patients was significantly higher in patients receiving bitherapy, compared to the others (p=0.007). The most frequently reported adverse event was somnolence (5.1%); three serious adverse events were reported. In everyday practice, zonisamide is principally used in association with other antiepileptic drugs for the treatment of focal epilepsy in adults. It is effective in improving seizure control and quality of life, and is generally well-tolerated

Long-Term Effectiveness, Safety and Tolerability of Fingolimod in Patients with Multiple Sclerosis in Real-World Treatment Settings in France: The VIRGILE Study

Online ahead of printInternational audienceIntroduction: It is important to confirm the effectiveness and tolerability of disease-modifying treatments for relapsing-remitting multiple sclerosis (RRMS) in real-world treatment settings. This prospective observational cohort study (VIRGILE) was performed at the request of the French health authorities. The primary objective was to evaluate the effectiveness of fingolimod 0.5 mg in reducing the annualised relapse rate (ARR) in patients with RRMS.Methods: Participating neurologists enrolled all adult patients with RRMS starting fingolimod treatment between 2014 and 2016, who were followed for 3 years. Follow-up consultations took place at the investigator's discretion. The primary outcome measure was the change in ARR at month 24 after fingolimod initiation. Relapses and adverse events were documented at each consultation; disability assessment (EDSS) and magnetic resonance imagery were performed at the investigator's discretion.Results: Of 1055 eligible patients, 633 patients were assessable at month 36; 405 (64.0%) were treated continuously with fingolimod for 3 years. The ARR decreased from 0.92 ± 0.92 at inclusion to 0.31 ± 0.51 at month 24, a significant reduction of 0.58 [95% CI - 0.51 to - 0.65] relapses/year (p < 0.001). Since starting fingolimod, 461 patients (60.9%) remained relapse-free at month 24 and 366 patients (55.5%) at month 36. In multivariate analysis, no previous disease-modifying treatment, number of relapses in the previous year and lower EDSS score at inclusion were associated with a greater on-treatment reduction in ARR. The mean EDSS score remained stable over the course of the study. Sixty-one out of 289 (21.1%) patients presented new radiological signs of disease activity. Treatment-related serious adverse events were lymphopenia (N = 21), bradycardia (N = 19), elevated transaminases (N = 9) and macular oedema (N = 9).Conclusions: The effectiveness and tolerability of fingolimod in everyday clinical practice are consistent with findings of previous phase III studies. Our study highlights the utility of fingolimod for the long-term management of patients with multiple sclerosis