53 research outputs found
Durability of composite materials in extreme conditions : resistance to fire and evolution of mechanical properties
No full textLes matériaux composites jouent un rôle de plus en plus important dans notre société dans de très nombreux domaines (aéronautique, naval, génie civil), de par leurs avantages en terme de légèreté, d’inaltérabilité et de rigidité. Il est donc primordial de comprendre et d’évaluer leurs propriétés sur le long terme (durabilité). Cependant, l’utilisation de ce type de matériau nécessite des précautions particulières notamment en ce qui concerne la tenue au feu. En effet, les composites sandwichs sont hautement inflammables et résistent mal à la chaleur. L’objectif de ce projet de thèse est d’étudier de manière combinée la durabilité thermo-mécanique (tenue au feu) de matériaux composites sandwichs à matrice polymère par le biais de mesures expérimentales au cône calorimètre. Il s'agit également de modéliser les variations de propriétés mécaniques induites en fonction de la température et du temps de combustion, en utilisant un modèle multiphysique basé sur une approche éléments finis (Abaqus). Les processus de dégradation thermique de ces matériaux sont présentés en fonction de la température et du temps, ainsi que les lois de comportement et les modèles d’estimation des propriétés thermiques et mécaniques. Un modèle numérique thermique amélioré est programmé sur le logiciel Abaqus et validé en lien avec des mesures expérimentales de tenue au feu (four, cône calorimètre). Des confrontations mesures expérimentales / modèle numérique, effectuées sur plusieurs configurations de scénario de tenue au feu, sont réalisées afin de comprendre et prédire le comportement et les propriétés thermo-mécaniques des matériaux composites sandwichs.Composite materials play an increasingly important role in our society in many fields (aeronautics, naval, civil engineering), because of their advantages in terms of lightness, unalterability and rigidity. It is therefore essential to understand and evaluate their properties in the long term (durability). However, the use of this type of material requires special precautions, particularly with regard to fire resistance. Indeed, sandwich composites are highly flammable and poorly heat resistant. The aim of this thesis project is to study in a combined way the thermomechanical durability (fire resistance) of polymer matrix composite sandwich materials by means of experimental measurements with a calorimeter cone. It is also a question of modeling the variations of mechanical properties induced as a function of the temperature and the combustion time, using a multiphysical model based on a finite element approach (Abaqus). The processes of thermal degradation of these materials are presented as a function of temperature and time, as well as behavior laws and of thermal and mechanical properties predictions. An improved thermal numerical model is programmed and validated in relation to experimental fire resistance measurements (oven, calorimeter cone). Confrontations between experimental measurements and numerical model, performed under several fire resistance scenario configurations, are carried out in order to understand and predict the behavior and thermomechanical properties of composite sandwich materials
Rerum moscoviticarum commentarii
No full textEnth. außerdem: De Admirandis Hvngariae Aqvis, Hypomnemation / Georgio Vuernhere author
De cultu ignis apud gentiles
No full textquam ... praeside ... I. Georgio Altmanno ... publico examini exponit Theoph. Sigismundus Gruner, Bernas ... author & respondens ... ad diem Febr. 1736. ...Errata auf S. 48Diss. Hohe Schule Bern, 173
Dissertatio Iuridica De Praeferentia Creditorum In Concursu, Eorundemque Privilegiis
No full textQuam ... Praeside Dn. Georgio Wernero, ICto, ... Pro virili publice tuebitur Henrich Eberhard von Anderten/ Author & Respondens Ad diem V. Augusti In Maiori Novi Iulei Auditori
Opera omnia
No full textAccurante Georgio HornioVorlageform des Erscheinungsvermerks: Amstelodami, Apud Elzevirios. Lugd: Bat: et Roterod: Apud Hackios. } A. 1665.Enth. außerdem: Vita Sulpici[i] Severi / Cl. Gerhardo Johanne Vossio Author
De lege amortizationis in Ducatibus Juliae et Montium vigente
No full textQuam ... Praeside Georgio Josepho Wedekind ... Author Et Defendens Ferdinandus Josephus Ignat. Schweren Berchemio-Juliacensis Ad Diem V. Septembris, Anno MDCCLXXVII ...Georgius Josephus Wedekind. [Resp.:] Ferdinandus Josephus Ignat. SchwerenHeidelberg, Univ., Jur. Diss., 5. Sept. 177
Disputatio Philosophica, exhibens Solis Quietem Et Terrae Motum
No full textQuam ... Praeside ... Dn. Georgio Othone ... Ad diem 23. August. Anno M.DC.XC. ... publice ventilaudam proponit Johan. Wernerus Baur/ Author & RespondensDruck mit allgemein formulierter Widmung "Deo Patriae & Amicis" auf der Rückseite des Titelbl
Dissertatio philosophico-politica, sistens curam magistratus de otio è republica tollendo
No full textquam ... praeside ... I. Georgio Altmanno ... eruditorum iudicio atque placidae disquisitioni ... subiicit author Ioh. Iacobus Wolfius, SS. min. cand. Bernae ... ad diem XIV. Augusti anni MDCCXXXVII.Diss. Hohe Schule Bern, 173
Design, thermal-mechanical coupling analysis, and optimization of polymeric matrix composite sandwiches with a lattice core exposed to a high temperature
No full textInternational audienceThis study presents the design of a sandwich structure tailored for post-heat transfer applications subjected to out-of-plane compression. A three-dimensional finite element simulation model was developed to analyze the temperature distribution within the sandwich structure and investigate the effects of high-temperature exposure on its mechanical behaviors. The structure was subjected to a temperature of 300 °C for 400 s, and the temperature distribution at the upper connection point between the top face sheet and the struts of the core was determined. Subsequently, upon returning the sandwich to ambient temperature, a comprehensive calculation of its mechanical properties was conducted and then enhanced by applying different optimization techniques. The results demonstrate that filling the core with Saffil alumina fibers in the presence of a 1.5 mm a thermal barrier coating of Superwool 607 helps increase the mechanical properties of the sandwich structure by around 55%
Durabilité des matériaux composites en conditions extrêmes : vers la prédiction de la tenue au feu
No full textInternational audienc
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