The purpose of this research is to investigate the structural efficiency of 8-node IsoTruss structures subject to uniaxial compression using numerical, dimensional, and optimization methods. The structures analyzed herein are based on graphite/epoxy specimens that were designed for light-weight space applications, and are approximately 10 ft. (3 m) long and 0.3 lb. (0.14 kg). The principal failure modes considered are material failure, global buckling, local buckling at the bay level, and longitudinal strut buckling. Studies were performed with the following objectives: to correlate finite element predictions with experimental and analytical methods; to derive analytical expressions to predict bay-level buckling; to characterize interrelations between design parameters and buckling behavior; to develop efficient optimization methods; and, to compare the structural efficiency of outer longitudinal configurations with inner longitudinal configurations. Finite element models were developed in ANSYS, validated with experimental data, and verified with traditional mechanics. Data produced from the finite element models were used to identify trends between non-dimensional Pi variables, derived with Buckingham's Pi Theorem. Analytical expressions were derived to predict bay-level buckling loads, and verified with dimensional analyses. Numerical and dimensional analyses were performed on IsoTruss structures with outer longitudinal members to compare the structural performance with inner longitudinal configurations. Analytical expressions were implemented in optimization studies to determine efficient and robust optimization techniques and optimize the inner and outer longitudinal configurations with respect to mass. Results indicate that the finite element predictions of axial stiffness and global buckling loads correlate with traditional mechanics equations, but overestimate the capacity demonstrated in previously published experimental results. The buckling modes predicted by finite element predictions correlate with traditional mechanics and experimental results, except when the local and global buckling loads coincide. The analytical expressions derived from mechanics to predict local buckling underestimate the constraining influence of the helical members, and therefore underestimate the local buckling capacity. The optimization analysis indicates that, in the specified design space, the structure with outer longitudinal members demonstrates a greater strength-to-weight ratio than the corresponding structure with inner longitudinal members by sustaining the same loading criteria with 10% less mass.

This project concerns the computational solution of inverse problems formulated as partial differential equation (PDE)-constrained optimization problems with interior data. The areas addressed are twofold. First, we present a novel software architecture designed to solve inverse problems constrained by an elliptic system of PDEs. These generally require the solution of forward and adjoint problems, evaluation of the objective function, and computation of its gradient, all of which are approximated numerically using finite elements. The creation of specialized "layered"' elements to perform these tasks leads to a modular software structure that improves code maintainability and promotes functional interoperability between different software components. Second, we address issues related to forward model definition in the presence of boundary condition (BC) uncertainty. We propose two variational formulations to accommodate that uncertainty: (a) a Bayesian formulation that assumes Gaussian measurement noise and a minimum strain energy prior, and (b) a Lagrangian formulation that is completely free of displacement and traction BCs. This work is motivated by applications in the field of biomechanical imaging, where the mechanical properties within soft tissues are inferred from observations of tissue motion. In this context, the constraint PDE is well accepted, but considerable uncertainty exists in the BCs. The approaches developed here are demonstrated on a variety of applications, including simulated and experimental data. We present modulus reconstructions of individual cells, tissue-mimicking phantoms, and breast tumors.

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This master thesis deal with design of elevator cabin frame. Working load of frame is 630 kg (8 people). Speed of elevator is 1m/s. This work also contains final element analysis of frame. Frame structure is analyzed by software I-DEAS.

This diploma thesis deals with design of a frame of a lift, whose roading capacity is 400 kg (5 people) and it olso deals with calculation of maximum distance between armatures of quides. Nominal speed is 1 m.s -1. This diploma thesis also includes final element analysis of the frame. The frame structure is analysed by software I – DEAS.

Calculating frame of elevator cage 1000kg, suggestion changes of frame according to calculation from MKP.

This diploma thesis deals with the design of disability traction elevator cabin OTI 630 / 0,63. In addition, the mounting procedure of the cabin, the calculation of the floor frame finite element metod in the program I-DEAS and the creation of drawings.

La fabrication de grandes pièces structurelles aéronautiques en alliage d’aluminium nécessite la réalisation de multiples étapes de mise en forme (laminage, matriçage, forgeage…), de traitements thermiques et usinage. Pendant ces étapes de fabrication, les différents chargements thermomécaniques subis par la pièce avant son usinage induisent des déformations plastiques ainsi que des modifications de la microstructure qui sont sources de contraintes résiduelles. A ces contraintes résiduelles issues de l’histoire thermomécanique de la pièce, viennent s’ajouter celles issues directement de l'étape d'usinage. En effet lors de cette étape jusqu’à 90% de la matière initiale d'une pièce peut être retirée en utilisant des conditions de coupe parfois sévères. Les pièces aéronautiques présentent parfois des géométries complexes avec des parois minces. Ainsi, pendant et à l’issue de l’usinage, la géométrie de la pièce usinée se trouve fortement modifiée et une redistribution des contraintes résiduelle est alors à l’œuvre. Ces contraintes résiduelles qu’elles soient héritées ou induites par le procédé, influencent fortement la géométrie finale obtenue et sont une des causes principales de non-conformité des pièces avec les tolérances dimensionnelles du produit fini. Engendrant une perte conséquente pour les industries manufacturières. Au cours de ce travail de thèse, nous nous sommes concentrés sur la prise en compte de ces deux types de contraintes résiduelles dans un modèle numérique de prédiction des distorsions. Nous nous sommes uniquement focalisés sur les pièces en aluminium issues de l’aéronautique. Nous avons ainsi couplé des modèles numériques avancés d’immersion et de remaillage avec un logiciel industriel existant afin de proposer une nouvelle solution numérique, rapide et robuste. En se basant sur les hypothèses de la littérature nous avons décidé de simuler l’usinage comme un enlèvement de matière massif où la trajectoire de l’outil et les machine seront négligées. L’objectif numérique est donc de proposer une méthode qui puisse rendre compte de la redistribution des contraintes résiduelles au sein de la pièce. Chaque étape de la gamme d’usinage est ainsi représentée par une étape de remaillage où le « volume usiné » sera supprimé du maillage pour céder ensuite sa place à un calcul mécanique permettant de rendre compte de la réorganisation des contraintes et les déformations qu’elle induisent. Ce processus itératif, réalisé dans un environnement parallèle a nécessité de nombreux développements numériques. Ainsi une nouvelle stratégie de remaillage et de repartitionnement a été proposée pour pouvoir obtenir un maillage à même de capturer les contraintes résiduelles issues de l’usinage en proche surface ainsi que pour réduire de manière significative les temps de calcul liés aux modifications de la géométrie par la découpe. Un modèle d’élasticité linéaire simplifié a aussi été ajouté au programme pour réduire le coût numérique des calculs mécaniques et permettre de traiter des problèmes de taille plus conséquente sur des ordinateurs de puissance raisonnable. Afin de confirmer les résultats obtenus par ces calculs, les simulations ont été comparées à des résultats expérimentaux tirés de la littérature et réalisés spécifiquement pour ce travail de thèse. / The manufacture of large aeronautical structural parts made of aluminium alloys requires multiple forming steps (rolling, die forging, forging, etc.), heat treatment and machining. During these manufacturing steps, the various thermomechanical loads suffered by the part before its machining induce plastic deformations as well as modifications of the microstructure which are sources of residual stresses. In addition to these residual stresses resulting from the thermomechanical history of the part, others result directly from the machining step. Indeed, during this step, up to 90% of the raw material of a part can be removed using sometimes severe cutting conditions. Aeronautical parts sometimes have complex geometries with thin walls. Thus, during and after machining, the geometry of the machined part is significantly modified by the redistribution of residual stresses at work. These residual stresses, whether inherited or induced by the process, strongly influence the final geometry obtained and are one of the main causes of non-conformity of the parts with the dimensional tolerances of the finished product. This results in a significant loss for manufacturing industries. In this thesis work, we focused on considering these two types of residual stresses in a numerical model predicting distortions. We focused only on aluminium parts from the aeronautics industry. We have thus coupled advanced numerical fitting and remeshing models with existing industrial software to provide a new numerical solution, fast and efficient. Based on the assumptions in the literature, we decided to model machining as a massive material removal where tool path and interaction with the machine will be neglected. The numerical objective is therefore to propose a method that can account for the redistribution of residual stresses within the part. Each step of the machining plan is thus represented by a remeshing step where the "machined volume" will be removed from the mesh followed by a mechanical computation to account for the reorganization of stresses and the deformations they induce. This iterative process, carried out in a parallel environment, required many numerical developments. Thus, a new remeshing and repartitioning strategy has been proposed to obtain a mesh capable of capturing the residual stresses resulting from near-surface machining and to significantly reduce the calculation times associated with changes in geometry through cutting. A simplified linear elasticity model has also been added to the approach to reduce the numerical cost of mechanical computation and allow for larger problems to be addressed on computers of reasonable power. In order to confirm the results obtained by these computations, the simulations were compared with experimental results from the literature and carried out specifically for this thesis work.

In the recent past, the field of scientific computing has become of more and more importance for scientific as well as for industrial research, playing a comparable role as experiment and theory do. This success of computational methods in scientific and engineering research is next to the enormous improvement of computer hardware to a large extend due to contributions from applied mathematicians, who have developed algorithms which make real life applications feasible. Examples are adaptive methods, high order discretization, fast linear and non-linear solvers and multi-level methods. The application of these methods in a large class of problems demands for suitable and robust tools for a flexible and efficient implementation. In order to play a crucial role in scientific and engineering research, besides efficiency in the numerical solution, also efficiency in problem setup and interpretation of simulation results is of utmost importance. As modeling and computing comes closer together, efficient computational methods need to be applied to new sets of equations. The problems to be addressed by simulation methods become more and more complicated, ranging over different scales, interacting on different dimensions and combining different physics. Such problems need to be implemented in a short period of time, solved on complicated domains and visualized with respect to the demand of the user. %Only a modular abstract simulation environment will fulfill these requirements and allow to setup, solve and visualize real-world problems appropriately. In this work, the concepts and the design of the C++ finite element toolbox AMDiS (adaptive multidimensional simulations) are described. It is shown, how abstract data structures and modern software concepts can help to design user-friendly finite element software, which provides large flexibility in problem definition while on the other hand efficiently solves these problems. Also systems of coupled problems can be solved in an intuitive way. In order to demonstrate its possibilities, AMDiS has been applied to several non-standard problems. The most time-consuming part in most simulations is the solution of linear systems of equations. Multi-level methods use discretization hierarchies to solve these systems in a very efficient way. In AMDiS, such multi-level techniques are implemented in the context of adaptive finite elements. Several numerical results are given which compare this multigrid solver with classical iterative methods. Besides the development of more efficient algorithms also the growing hardware capabilities lead to an improvement of simulation possibilities. Modern computing clusters contain more and more processors and also personal computers today are often equipped with multi-core processors. In this work, a new parallelization approach has been developed which allows the parallelization of sequential code in a very easy way and reduces the communication overhead compared to classical parallelization concepts.

The continuous growth in road transportation demand requires the development towards sustainable strategies. The concept of Smart Roads is arising as a convergence of technologies that will lead the mobility by road into a more efficient and interactive system between infrastructure, environment and vehicles. Within this context, e-mobility appears as one of the key components. The implementation of e-mobility based on Electric Vehicles (EVs) has been restricted by numerous shortcomings such as their driving range, the battery size, the dependence on charging stations and the time required for its charging. However, the electrification of the road infrastructure, which will enable a dynamic charging of the EVs while driving, is becoming a potential solution to overcome these deficiencies. This study aims to contribute for the future introduction of electrified roads (eRoads) into the current network, by focusing on the effects and consequences of embedding Inductive Power Transfer (IPT) systems in the road infrastructure. A structural design of an eRoad is conducted through a Finite Elements Analysis (FEA) by analysing the behaviour of a pavement structure based on Swedish conditions subjected to traffic loading. Valuable conclusions can be displayed from this analysis and thus, a summary concerning considerations and effects over the design, construction and maintenance of eRoads can be built. Nevertheless, this analysis must be complemented and coordinated from a lifetime perspective to reach the social, environmental and economic requirements related to the development of road infrastructure nowadays. Hence, a guideline from a life cycle approach is stated over the integration of eRoads in order to enable the assessment of the infrastructure during its different phases. To be sustainable, the development of road infrastructure must reach not just structural and appropriate performance requirements, but also preserve the environmental and economic impact. This thesis pretends to combine all these aspects as a state of the art, providing a basis that stands out the most relevant issues related to the feasible implementation of eRoads in the mid-long term.