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Valdymo taisyklėmis ribojamų komponentų sąsajų specifikavimo metodika / Interface specification technique capturing control flow rulesBalandytė, Milda 31 May 2004 (has links)
This work presents development of Human Resource Management System based on analysis of modern development trends as well as fundamentals of key functions and data structures of human resource management systems in organizations. Introduced general-purpose model meets the requirements of human resource management systems and fits for the organizations of any size and structure. The system, mentioned above, was designed using ICONIX, Martin-Odell, RUP, XP, UMM methodologies, tested using black and white box techniques and implemented by means of Lotus Notes/Domino SDK . Created software was installed for the trial period at the joint-stock company 'PTI Technologijos'. The conceptual part of the theses represents component interface specification technique capturing control flow rules. It describes a clear process for moving from business requirements to system specification and identifying system behavior rules conditioning interfaces of the system. Proposed model facilitates dealing with the change and substitutability of business rules, what can be achieved only if the system is properly specified. Interface specification technique was used in practice to design the interface between human resource management system and accountancy system.
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Comportement élasto-plastique incrémental des poudres ductiles : simulation de l'écoulement plastique par la méthode des éléments finis multi-particules / Incremental elasto-plastic behaviour of ductile powders : Discrete simulation of the plastic flowAbdelmoula, Nouha 13 July 2016 (has links)
Cette thèse concerne la modélisation du comportement mécanique de poudres ductiles au cours de leur mise en forme par le procédé de compression à froid. L’approche utilisée consiste à modéliser la poudre par un échantillon numérique de 50 particules sphériques distribuées aléatoirement. Chaque particule est maillée en éléments finis avec un comportement élasto-plastique et interagit par contact avec ses voisines. Sous l’effet du chargement, les particules se déforment et subissent de grandes transformations.La méthode développée consiste à imposer aux frontières de l'échantillon numérique des conditions aux limites en déplacement ou en force afin de simuler une réponse continue équivalente en termes de contrainte-déformation pour plusieurs chemins de chargement depuis les faibles valeurs de densité relative jusqu'aux fortes valeurs. Outre le fait que la méthode permet d’appliquer par la simulation des chemins de chargement inaccessibles aux techniques expérimentales, elle fournit de nombreuses indications sur la phénoménologie du comportement aux frontières de l'échantillon en relation avec la morphologie des particules déformées plastiquement et l’évolution des surfaces de contact inter-particules.Cette réponse obtenue sera étudiée au moyen des notions de l'élasto-plasticité classique, à savoir la surface de charge et la loi d'écoulement. L'accent est mis sur l’analyse de l’écoulement plastique et l'existence du potentiel plastique. Les résultats montrent que la direction d’écoulement est approximativement unique pour les états de contrainte éloignés du point de chargement. En revanche, la direction d’écoulement cesse d’être unique à proximité de point de chargement, ce qui révèle le caractère anisotrope de l’écrouissage. Ce comportement, propre aux poudres ductiles, est intimement lié à la déformation des grains. La dégradation anisotrope des propriétés mécaniques résultant du mécanisme de dilatance est également étudiée. / This thesis is concerned with the modelling of the mechanical behaviour of ductile powders during cold compaction process. A numerical method was implemented, in which a powder sample was assimilated to an assembly of 50 meshed particles in a cubic box which was submitted to compressive loadings simulated by means of the finite element method. Each particle was meshed and assigned an elastic-plastic constitutive behaviour. Particles interacted through mechanical, frictional contact and underwent large transformation during loading.The method developped in the thesis consisted in imposing boundary conditions as displacements or forces on the bounding walls of the numerical sample. The mechanical response of the sample was averaged to obtain the equivalent response of a continuum in terms of stress and strain. Various loading paths, including loading paths that are technically not attainable by experimental means, were applied up to different values of relative densities, from low (60%) to high values (98%). Much information on the phenomenological behaviour of the numerical sample could be obtained, in relation with the morphology of deformed particles and the evolution of contact surfaces.The results were interpreted based on the concepts of classical elasto-plasticity, i.e., yield surface and flow rule. The main focus of the study was the analysis of incremental plastic flow and the existence of a plastic potential. Results showed that the flow rule postulate, based in the plastic potential, could be considered as valid for stress states relatively far from the loading point. In the vicinity of the loading point, the direction of the plastic strain increment vector ceases to be unique. This behaviour, which is an original feature of ductile powders mechanical behaviour, was attributed to the anisotropic strain-hardening processes at stake, related to the anisotropic formation of contact surfaces between particles. The drop in mechanical properties related to dilatancy was also studied.
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