Cartridge firing device designed for attachment, release and ejection of a satellite

The device functions were performed by a one-piece unit with resulting performances which were of interest regarding the satellite attachment and the accuracies of the path and velocity during separation and ejection. A gain in weight may be obtained relative to the conventional device used, i.e. maintenance belt, belt unlocking device, pusher spring, and cartridge fired pusher

On the use of simulated experiments in designing tests for material characterization from full-field measurements

The present paper deals with the use of simulated experiments to improve the design of an actual mechanical test. The analysis focused on the identification of the orthotropic properties of composites using the unnotched Iosipescu test and a full-field optical technique, the grid method. The experimental test was reproduced numerically by finite element analysis and the recording of deformed grey level images by a CCD camera was simulated trying to take into account the most significant parameters that can play a role during an actual test, e.g. the noise, the failure of the specimen, the size of the grid printed on the surface, etc. The grid method then was applied to the generated synthetic images in order to extract the displacement and strain fields and the Virtual Fields Method was finally used to identify the material properties and a cost function was devised to evaluate the error in the identification. The developed procedure was used to study different features of the test such as the aspect ratio and the fibre orientation of the specimen, the use of smoothing functions in the strain reconstruction from noisy data, the influence of missing data on the identification. Four different composite materials were considered and, for each of them, a set of optimized design variables was found by minimization of the cost function

Exploration of Saint-Venant’s Principle in inertial high strain rate testing of materials

Current high strain rate testing procedures of materials are limited by poor instrumentation which leads to the requirement for stringent assumptions to enable data processing and constitutive model identification. This is the case for instance for the well known Split Hopkinson Pressure Bar (SHPB) apparatus which relies on strain gauge measurements away from the deforming sample. This paper is a step forward in the exploration of novel tests based on time and space resolved kinematic measurements obtained through ultra-high speed imaging. The underpinning idea is to use acceleration fields obtained from temporal differentiation of the full-field deformation maps measured through techniques like Digital Image Correlation (DIC) or the grid method. This information is then used for inverse identification with the Virtual Fields Method. The feasibility of this new methodology has been verified in the recent past on a few examples. The present paper is a new contribution towards the advancement of this idea. Here, inertial impact tests are considered. They consist of firing a small steel ball impactor at rectangular free standing quasi-isotropic composite specimens. One of the main contributions of the work is to investigate the issue of through thickness heterogeneity of the kinematic fields through both numerical simulations (3D finite element model) and actual tests. The results show that the parasitic effects arising from non uniform through-the-thickness loading can successfully be mitigated by the use of longer specimens, making use of Saint-Venant's principle in dynamics

A Sociological Study of the French-Speaking People in Chauvin, a Line Village in Terrebonne Parish A L

This study an attempt has been made to analyse the social structure of Chauvin, a line village on Bayou Petit Caillou in Terrebonne Parish in southern Louisiana. The following characteristics were selected for analysis: first, the descent of the families in the community; second, the language composition of the population in the community; third, the religious life and religious affiliation of the people in the community; fourth, the occupational and economic characteristics of the natives of Chauvin; fifth, the educational facilities, and the attitudes toward education; sixth, the housing conditions found in the village; and seventh, the sooial activities of the population in the village. The writer is well acquainted in Chauvin, having a brother living there, as well as many other relatives. Data for this study were obtained in a survey of one hundred and fifty-three homes, from studying sources in the library of ths University of Louisiana, and by interviewing the natives, many of whom the writer has known since childhood. Throughout the study particular attention was concentrated on the form of settlement represented by this community. It was found that this type of settlement made possible many sooial advantages instrumental in fostering the social solidarity and sooial cohesion found in Chauvin. The population is not only characterised by a high percent of home ownership, but, since the community derives its existence from the sea, by boat ownership as well.Tho Catholic Church is the only church in Chauvin and it exerts a tremendous influence on the homes of these people. A peculiar characteristic is the retention of much of the French influence. This social heritage plus the social control exercised by the church have made these a delightful people one who is able to laugh, and work, and live

Texture evolution in Nd:YAG-laser welds of AZ31 magnesium alloy hot rolled sheets and its influence on mechanical properties

AZ31 hot rolled magnesium alloy presents a strong basal texture. Using laser beam welding (LBW) as a joining process induces high temperature gradients leading to major texture changes. EBSD was used to study the texture evolution, and tensile tests coupled with speckle interferometry were performed to understand its influence on mechanical properties. The random texture obtained in the LBW fusion zone is mainly responsible for the yield strength reduction.AEROMAG Project N°AST4-CT-2005-516152 European Unio

Enquête qualitative 2016 - Bibliothèque municipale de Lyon

La Bibliothèque municipale de Lyon a mené, en complément des enquêtes quantitatives (Baromètres 2013 et 2015), une enquête qualitative qui précise encore les attentes du public lyonnais. Elle a l’originalité d’interroger non seulement des abonnés et « décrocheurs », mais aussi des non usagers de la bibliothèque. Associant dans l’examen des entretiens des méthodes linguistiques d’analyse de discours, elle révèle non seulement des pratiques (culturelles, numériques, de lecture) et des stratégies (d’information, d’approvisionnement, d’appropriation), mais aussi la prégnance des représentations et des « insécurités culturelles » qui président à la fréquentation, aux usages, à la prise d’information… En quoi cette enquête, aboutissant à des préconisations concrètes que la BmL prendra le temps d’examiner pour compléter son Projet d’Etablissement, dans les années qui viennent, dépasse aussi le cadre lyonnais et peut contribuer à une meilleure compréhension du public en général