For the purpose of mechanical impact energy absorption in the transport industry are mainly used special profile absorbers. For highly specialized applications is required to use components that are designed for specific kind of deformation. Example of these parts are industrial-made metal foams or micro-lattice structures produced by SLM technology. This paper focuses on low-velocity dynamic loading prediction of BCC micro-lattice structure made of aluminum alloy AlSi10Mg by SLM technology (SLM 280HL). For this purpose dynamic FEM simulaton of the micro-lattice structure was developed, supplemented by model of BCC structure material obtained from mechanical testing. Real geometry of tested samples obtained from optical measurement (Atos Triple Scan III) was further implemented in the numerical model. Dynamic BCC structure load experiment was performed on a drop-weight tester. Behavior of structured material in drop-weight test was described by the course of deformation and reaction forces over time. Comparable results were obtained for flat loading of dynamic FEM simulation and experiment. Inclusion of production phenomena in simulation led to increased accuracy and compliance with experiment. Tool for testing the effect of geometry change on mechanical properties was created. To achieve more accurate results with puncture load, it is necessary to modify the material model with real material deformation at test sample failure.

Předložená dizertační práce je součástí většího výzkumného projektu, který si klade za cíl využití mikro prutové konstrukce vyrobené technologií SLM jako absorbér rázové energie s přesně navrženými vlastnostmi. Hlavním cílem práce je vývoj numerického modelu deformačního chování mikro-prutové konstrukce vyrobeného technologií Selective Laser Melting (SLM) z materiálu AlSi10Mg. Aby bylo možné dosáhnout hlavního cíle dizertační práce, bylo nutné analyzovat vliv procesních parametrů technologie SLM na tvorbu vnitřních materiálových vad a drsnost povrchu při výrobě mikro-prutové konstrukce. Tyto imperfekce degradují její mechanické vlastnosti a jejich odstranění zlepší možnosti a přesnost numerické predikce. Výsledky ukazují významný vliv dvou hlavních parametrů – skenovací rychlosti laseru a výkonu laseru. Na základě těchto poznatků byly dále definovány parametry vstupní energie Ein a lineární energie Elin, které zahrnují oba zmíněné parametry a byly definovány jejich limitní hodnoty pro minimalizaci vzniklých imperfekcí. Deformační chování vyrobené mikro-prutové konstrukce bylo analyzováno na navrženém pádové zařízení, které umožňuje testování s dopadovou energií až 120 J. Deformační chování je vyhodnocováno s využitím obrazové analýzy záznamu vysoko rychlostní kamery a silového průběhu z tenzometru. Výsledky analýzy byly využity pro validaci numerického modelu v programu ANSYS Explicit, do kterého byly implementovány poznatky o reálném tvaru vyrobeného mikro-prutového materiálu ve formě eliptického modelu geometrie a informace o reálných mechanických vlastnostech ve formě vyvinutého materiálového modelu. Výsledné porovnání výsledků experimentu s predikcí numerického modelu ukazují dobrou shodu v místě maximálního zatížení Fmax (odchylka 5 %) i průběhu celé deformace vzorku. Tyto poznatky budou v budoucnu využity při návrhu absorbéru energie s definovanými mechanickými vlastnostmi.

The subject of this Master’s thesis was recalculation and design two variants of existing supporting steel structure storey administrative building which is located in the complex of Jihomoravská plynárenská a.s. in the city center of Brno. Dimensions and disposition based on the specifications of the Master‘s thesis. The total height of the structure is 29.46 m and circular platform has a diameter of 16.088 m. The supporting structure of an existing building consists of circumferential lattice structure. The main supporting elements of both variants are columns. Option A has 8 columns. Option B has 16 columns. These two variants were preliminarily designed and statically evaluated. After that was made a comparison of variants, and one was selected for more detailed processing (Option A). This included the calculation of anchorage, draft of mounting joints, technical report and drawing documentation.

Metal additive technology allows to create objects with complex shape that are very difficult to produce by conventional technologies. An example of such component is a porous structure which is composed of periodical truss cells. This diploma thesis deals with the prediction of the mechanical properties of very small lattice structures made of additive manufacturing technology Selective Laser Melting. Using the proposed test specimens it was found that real dimensions of the trusses varies with size and orientation to the base platform. It was proposed and tested samples for rod tensile test made of SLM. Based on the real information about dimensions and mechanical properties of rods were predicted mechanical properties of lattice structures. A lot of mechanical tests were carried out to obtain the real mechanical properties. Test results and conclusions are described in the thesis.

Durch die Verwendung von 3D-Druck-Verfahren wird die Gestaltung der Komponenten revolutioniert, weil die Form nicht mehr abhängig vom Fertigungsverfahren ist. Dabei werden auch optimale Gitterstrukturen innerhalb der Komponenten immer wichtiger. Diese Stützstrukturen können in Creo Parametric 4.0 mit dem neuen «Lattice-Feature» modelliert und Creo Simulate analysiert werden. Parallel dazu kann man mit ProTopCI (Hersteller CAESS, PTC Partner Advantage, Silver) eine Topologieoptimierung mit Stützstrukturen durchführen. Der Vortrag beleuchtet die Unterschiede dieser 2 Methoden.

Main topic of this Masters Thesis is design of railway station for high speed line railway. Building site is situated in East Moravian region in the district of Brno-Tuřany. The building is designed as a detached two-storey object standing on the bridge over the railway. Mass of the building consists of two trimmed blocks which are mutually mirrored. The mass of both parts of the building is pervaded by illuminating stripe. Its shape is also based on the shape of trimmed block and rises over the surrounding surfaces. There are placed vertical paths in the stripes. It helps passengers in orientation because these are visible even from the outside of the building. This arrangement of individual masses symbolizes both direction of the arrival of trains to the station. There is placed arrival and departure hall in the middle of the object. Its height is similar to the height of the object itself. The hall is surrounded by the service facilities of the railway station situated on two floors. The supporting structure is made of steel. Both peripheral housing and roof are supported by the frame construction consisting of planar lattice beams. Construction of the façade is composed of frame system Wicona. The peripheral housing is tiled with panels of expanded metal.

Wikipedia umschreibt die Topologieoptimierung als ein computerbasiertes Berechnungsverfahren, durch welches eine günstige Grundgestalt (Topologie) für Bauteile unter mechanischer Belastung ermittelt werden kann. Durch die Verwendung von 3D-Druck-Verfahren wird die Gestaltung der Komponenten revolutioniert, weil diese nicht mehr abhängig vom Fertigungsverfahren sind. Dabei werden auch optimale Gitterstrukturen innerhalb der Komponenten immer wichtiger. Diese neuen Herausforderungen können im Creo Umfeld mit ProTopCI (Hersteller CAESS, PTC Partner Advantage, Silver) elegant gelöst werden. Im Vortrag (mit Live-Demonstration) werden die neuen Möglichkeiten dieser innovativen Lösung beleuchtet: Modellerzeugung in Creo Simulate (FEM-Mode): - Verschiedene Lastfälle, - Kontakte, - Schraubenverbindungen, - CAD-Geometrie, - zu optimierende Bereiche, ... Technologische Randbedingungen zur Berücksichtigung des Fertigungsverfahren Innovatives Erzeugen/Optimieren der Gitterstrukturen Glätten, Exportieren der optimierten Geometrie

This thesis deals with static and dynamic analysis of an lookout tower construction. For dynamic analysis a computational model in ANSYS software is created. Static analysis is performed by Scia Engineer software. Both of this software use finite element method. It is also focused on wind load determination by Eurocode 1, structural factor calculation, modal analysis and vortex shedding. Verification of selected parts according to Eurocodes is included.

Le développement de la fabrication additive permet d'élaborer des pièces de forme extrêmement complexes, en particulier des structures alvéolaires ou "lattices", où l'allégement est recherché. Toutefois, cette technologie, en très forte croissance dans de nombreux secteurs d'activités, n'est pas encore totalement mature, ce qui ne facilite pas les corrélations entre les mesures expérimentales et les simulations déterministes. Afin de prendre en compte les variations de comportement, les approches multiparamétriques sont, de nos jours, des solutions pour tendre vers des conceptions fiables et robustes. L'objectif de cette thèse est d'intégrer des incertitudes matérielles et géométriques, quantifiées expérimentalement, dans des analyses de flambement. Pour y parvenir, nous avons, dans un premier temps, évalué différentes méthodes de substitution, basées sur des régressions et corrélations, et différentes réductions de modèles afin de réduire les temps de calcul prohibitifs. Les projections utilisent des modes issus soit de la décomposition orthogonale aux valeurs propres, soit de développements homotopiques ou encore des développements de Taylor. Dans un second temps, le modèle mathématique, ainsi créé, est exploité dans des analyses ensemblistes et probabilistes pour estimer les évolutions de la charge critique de flambement de structures lattices. / The development of additive manufacturing allows structures with highly complex shapes to be produced. Complex lattice shapes are particularly interesting in the context of lightweight structures. However, although the use of this technology is growing in numerous engineering domains, this one is not enough matured and the correlations between the experimental data and deterministic simulations are not obvious. To take into account observed variations of behavior, multiparametric approaches are nowadays efficient solutions to tend to robust and reliable designs. The aim of this thesis is to integrate material and geometric uncertainty, experimentally quantified, in buckling analyses. To achieve this objective, different surrogate models, based on regression and correlation techniques as well as different reduced order models have been first evaluated to reduce the prohibitive computational time. The selected projections rely on modes calculated either from Proper Orthogonal Decomposition, from homotopy developments or from Taylor series expansion. Second, the proposed mathematical model is integrated in fuzzy and probabilistic analyses to estimate the evolution of the critical buckling load for lattice structures.

[pt] Os recentes avanços das técnicas de manufatura aditiva vêm ampliando a sua flexibilidade em fabricar peças complexas em escala cada vez menores. Neste contexto, o projeto de microestruturas porosas vem se destacando na comunidade científica devido a capacidade de se otimizar a topologia da célula para atender aos requisitos de projeto. No entanto, existem vários desafios que dificultam a fabricação de peças obtidas pelo método de otimização topológica multiescala, dentre eles, a conectividade das microestruturas. A otimização topológica multiescala consiste na otimização tanto da macroescala, estrutura global, quanto da microescala, microestrutura do material. O objetivo principal deste trabalho é desenvolver um esquema eficaz para garantir a transição entre as diferentes microestruturas de material obtidas na otimização multiescala. As metodologias multiescala de otimização topológica simultânea de ambas as escalas e os procedimentos de homogeneização são descritos. Apresentam-se os principais aspectos numéricos e computacionais destes métodos, assim como exemplos ilustrativos. / [en] Recent advances in additive manufacturing techniques have increased their flexibility in making complex parts on a smaller scale. In this context, the design of porous microstructures has been standing out in the scientific community due to the ability to optimize the cell topology to meet the design requirements. However, there are several challenges that inhibit the fabrication of optimized parts obtained by the multi-scale topology optimization method, such as the connectivity of microstructures. The multiscale topological optimization consists of the optimization of both the macro-scale, global structure, and the micro-scale, microstructure of the material. The main objective of this work is to develop an effective scheme to guarantee compatibility in the transition between the different material microstructures obtained in multiscale optimization. The multiscale methodologies for simultaneous topological optimization of both scales and the homogenization procedures are described. The main numerical and computational aspects of these methods are presented, as well as representative examples to illustrate the capabilities of the proposed scheme.