Earthquakes represent a serious threat to the safety of masonry structures, with failure of these constructions under the influence of seismic action generally occurring via specific, well-documented collapse mechanisms. Analysis and assessment of these collapse mechanisms remains a challenge - while most analysis tools are time-consuming and computationally expensive, typical assessment methods are too simplified and often tend to underestimate the dynamic resistance of the structures. This dissertation aims to bridge the gap between the two through the development of a computational tool for the seismic collapse assessment of masonry structures, which uses rocking dynamics to accurately capture large displacement response, without compromising on computational efficiency. The tool could be used for rapid evaluation of critical mechanisms in a structure in order to prioritise retrofit solutions, as well as for code-based seismic assessment. The framework of the tool is first presented, wherein the rocking equations of motion are derived for a range of different collapse mechanisms, for any user-defined structural geometry, using as a starting point a geometric model of the structure in Rhino (a 3D CAD software). These equations of motion are then exported for solution to MATLAB. As a number of collapse mechanisms take place above ground level, a methodology to account for ground motion amplification effects is also proposed, while in the case of comparison of multiple different mechanisms, an algorithm to automatically detect critical mechanisms is presented. These developments make it possible to rapidly conduct a seismic analysis of structures with complicated three-dimensional geometries. However, the rocking equations of motion utilised thus far assume that the interfaces between the masonry macro-elements are rigid, which is not the case in reality. Thus, a flexible interface model is introduced, where the interfaces are characterised by a finite stiffness and compressive strength. This modelling strategy results in an inward shift of the rocking rotation points, and expressions are derived for these shifting rotation points for different interface geometries. The rocking equations of motion are also re-derived to account for the influence of the continuously moving hinges. However, the new equations tend to be highly non-linear - especially in the case of more complex collapse mechanisms. Thus to reduce computational burden, the semi-flexible interface model is proposed, which accounts for the shifting hinges in a more simplified manner than its fully-flexible counterpart. These new analytical models enable more accurate prediction of the seismic response of real-world structures, where interface flexibility tends to have a significant influence on dynamic response, while material damage in the form of crushing of the masonry also reduces dynamic resistance. The ability of the tool to be used for both seismic analysis and assessment is finally demonstrated by using it to perform a rocking dynamics-based analysis as well as a code-based seismic assessment of the walls of a historic earthen structure.

<p>A magnetostrictive material elongates when it is subjected to a magnetic field. This effect can then be used to design powerful actuators. The department of electromagnetic engineering has been working with magnetostricitve material and their applications since the 1980s and is presently engaged in a project focusing on magnetostrictive transducer utilisation for the aeronautic field.</p><p>The focus of the presented work has been to develop and improve methods and tools supporting the development of magnetostrictive actuators.</p><p>The axial-radial model was previously developed at the department and is well suited for circular cross sections of magnetostrictive rods. It is, however, common to laminate the magnetostrictive rods resulting in rectangular cross sections. The use of Cauer circuits allows modelling of the shielding effect. This shielding effect results in non-homogenous magnetisation and stress in both rectangular and circular cross sections of the rod. A model based on Cauer circuits, including a hysteresis model based on experimental data, was developed during the project. Furthermore, it is demonstrated how figures of merit and the use of finite element methods can be used to find optimised designs in a systematic and computational efficient way. The<i> modified generalised Fabry factor</i> <i>and the magnetisation inhomogeneity coefficient</i> are two proposed new figures of merit.</p><p>A Magnetostricitve material is characterised through an experimental procedure. Usually, magnetostrictive material exhibit large hysteresis. An important part of the material characterisation is the post-processing of the measurement data, including a de-hysterisation procedure. In the thesis, a de-hysterisation method which ensures energy consistent data is presented. Energy consistent material data is essential to achieve energy consistent simulations of magnetostrictive systems.</p><p>It is also demonstrated how the knowledge at the department can be utilised in international projects. In an ongoing project, the department is engaged in two sub tasks. In one of these sub tasks a high torque actuator is to be developed for the helicopter industry. The developed magnetostrictive models are used to perform system simulations of such actuator systems. In the other sub task a device for power harvesting from vibrations is analysed. It has now been shown how to adapt the load impedance in order to extract maximal electric power from the device.</p>

Thesis is focused on evaluation of available tools for 3D application development. In one selected tool (Blender) is created computer game. This game demonstrates Blender's capabilities. The process of creating is recorded in a case study for the possible purposes of own complex games development.

A magnetostrictive material elongates when it is subjected to a magnetic field. This effect can then be used to design powerful actuators. The department of electromagnetic engineering has been working with magnetostricitve material and their applications since the 1980s and is presently engaged in a project focusing on magnetostrictive transducer utilisation for the aeronautic field. The focus of the presented work has been to develop and improve methods and tools supporting the development of magnetostrictive actuators. The axial-radial model was previously developed at the department and is well suited for circular cross sections of magnetostrictive rods. It is, however, common to laminate the magnetostrictive rods resulting in rectangular cross sections. The use of Cauer circuits allows modelling of the shielding effect. This shielding effect results in non-homogenous magnetisation and stress in both rectangular and circular cross sections of the rod. A model based on Cauer circuits, including a hysteresis model based on experimental data, was developed during the project. Furthermore, it is demonstrated how figures of merit and the use of finite element methods can be used to find optimised designs in a systematic and computational efficient way. The modified generalised Fabry factor and the magnetisation inhomogeneity coefficient are two proposed new figures of merit. A Magnetostricitve material is characterised through an experimental procedure. Usually, magnetostrictive material exhibit large hysteresis. An important part of the material characterisation is the post-processing of the measurement data, including a de-hysterisation procedure. In the thesis, a de-hysterisation method which ensures energy consistent data is presented. Energy consistent material data is essential to achieve energy consistent simulations of magnetostrictive systems. It is also demonstrated how the knowledge at the department can be utilised in international projects. In an ongoing project, the department is engaged in two sub tasks. In one of these sub tasks a high torque actuator is to be developed for the helicopter industry. The developed magnetostrictive models are used to perform system simulations of such actuator systems. In the other sub task a device for power harvesting from vibrations is analysed. It has now been shown how to adapt the load impedance in order to extract maximal electric power from the device. / QC 20101115

Este trabalho foi desenvolvido no âmbito do Mestrado em Engenharia Informática e consiste na dissertação escrita para a obtenção do respectivo grau.Na origem e motivação deste trabalho esteve um hiato no conhecimento, que consistia em saber se se poderia usar indicadores de eficiência como instrumento para a monitorização e gestão de processos inerentes aos Serviços de Documentação e Informação, num contexto de optimização de processos e de prestação de contas aos stakeholders.Nesse sentido, começou-se este trabalho por fazer uma revisão da literatura acerca de abordagens existentes para a avaliação dos Serviços de Documentação e Informação e dos processos que lhes são inerentes, tendo sido estudadas 4 abordagens: valorização contingente, Balenced ScoreCards, indicadores e impactos.Seguidamente, foi feita a opção por uma das abordagens de avaliação estudadas. Nessa opção, foi tido em consideração que no caso de estudo que se utilizou neste trabalho - o Serviço de Documentação e Informação da Faculdade de Engenharia da Universidade do Porto - já é corrente a utilização de indicadores para avaliar o Serviço. Assim, optou-se por aprofundar a abordagem dos indicadores mas, ao nível dos processos.Posteriormente, após a análise e modelação do processo principal do Serviço - processo "Gerir documento" - identificou-se 6 indicadores de eficiência (3 de custo e 3 temporais) e, de acordo com a norma NP ISO 11620: 2004, desenvolveu-se a respectiva grelha descritiva, de modo a que estes possam ser usados por outros Serviços e até serem incluídos na norma numa fase posterior.Finalmente, foi feito um caderno de requisitos de um sistema que permitirá calcular os indicadores identificados, que consistiu no levantamento de requisitos e na respectiva modelização em UML.Palavras-chave:- Indicadores de eficiência;- Processos;- Serviços de Documentação e Informação. / This work was developed under the Informatics Engineering Master programme and is the written dissertation to obtain the respective degree.In the origin and motivation of this work was a hiatus in knowledge, which consisted in knowing whether it could be used efficiency indicators as a tool for monitorization and management of processes inherent to Library and Information Services, in a context of processes optimization and stakeholders rendering of accounts.In this orientation, this work had begun by doing a literature review on existing approaches for the evaluation of Library and Information Services and of its inherent processes. In that review 4 approaches were studied: contingent valuation, Balenced ScoreCards, indicators and outcomes.Then, a choice was made by one of the studied approaches. In that choice, has been taken into consideration that in the case study that was used in this work - the Library and Information Service of the Faculty of Engineering of the University of Porto - is common to use indicators to evaluate the Service. So, we decided to deepen the indicators approach but on the level of processes.Posteriorly, after the analysis and modeling of the main Service process, which name is "Gerir documento", 6 efficiency indicators were identified (3 of cost and 3 of time). Then, in concordance to the standard NP ISO 11620: 2004, was developed its descriptive framework, so that they can be used by other Services and eventually to be included in the standard.Finally, was developed a set of requisites for a system that will be able to calculate the identified indicators, which consisted in requisites gathering and the respective UML model.Keywords:- Efficiency indicators;- Processes;- Library and Information Services.