Com a evolução da medicina e o consequente envelhecimento da população, o aneurisma de aorta abdominal (AAA) se tornou uma doença cada vez mais presente, sobretudo em homens. A falta de conhecimento detalhado do comportamento mecânico do tecido aórtico abdominal é o principal gargalo no refinamento do critério para a recomendação de cirurgia corretiva, resultando, ainda hoje, no óbito decorrente da ruptura desses aneurismas. O entendimento do comportamento mecânico desse tecido permitirá o refinamento do critério atual, salvando mais vidas. Esse entendimento pode ser obtido através da Mecânica do Contínuo, utilizando dados experimentais de ensaios mecânicos para avaliar e descrever o comportamento do material. Para que isso ocorra, é necessário que o teste seja feito em dois eixos independentes. No presente trabalho, foram escolhidos os eixos longitudinal e circunferencial para a realização de testes mecânicos, levando em consideração aspectos de metodologias já utilizadas, seus pontos fortes e deficiências. São apresentados o projeto, a construção e e a calibração de um equipamento para ensaios biaxiais de tecidos biológicos tubulares, extraídos de cadáveres, e testados até a ruptura, com a possibilidade de realização de ensaios de pré-condicionamento. Tubos de látex foram utilizados na calibração do equipamento, de cuja utilização é esperada grande contribuição na ampliação do conhecimento da probabilidade de ruptura de AAAs e em uma melhor compreensão do comportamento do tecido da uretra peniana. / The evolution of Medicine has enabled humans to live longer. With that, the incidence of abdominal aortic aneurysms (AAAs) has grown, especially among males. The lack of detailed knowledge on the mechanical behavior of the abdominal aortic tissue is the main bottleneck in the improvement of the criterion for recommending corrective surgery. Therefore, many patients still die from the rupture of those aneurysms. Better understanding of the tissues mechanical behavior will allow the refinement of todays criterion, thus saving more lives. This understanding can be obtained from Continuum Mechanics, using mechanical test experimental data to evaluate and describe the behavior of the material. The data has to come from tests performed in two independet axes. This Masters thesis presents the project, manufacturing and calibration of an apparatus for the test of cylindrical biological tissues in two directions, longitudinal and circumferential. Aspects of pre-existent tests and methods and their positive and negative sides were taken into account. The specimens will come from cadavers, and it will be possible to pre-condition them, as well as to test them to the rupture. Latex tubes were used in the calibration of the apparatus, whose utilization is expected to improve the knowledge on AAA rupture probability, as well as to improve the comprehension of the penile urethral tissues behavior.

This diploma thesis deals with the structural design of the chucking jaws for RUMUL Cracktronic 160 testing machine. This apparatus is used in the fatigue laboratory of Institute of Machine Design FME BUT. Simplification, speed improvement and better test sample griping are expected gains of the new clamping system. Solidworks system is used to create 3D model of the jaws. Stress analysis is created by Finite element method in ANSYS Workbench software.

The main object of this thesis is the proposal of fitting (setting) hydraulic cylinder into test equipment of ball-joints of company TRW-DAS Dačice a.s. The thesis includes a short review about testing ball-joint of above company and about liquid mechanisms. Also, there are analyzed demands for fitting (setting) hydraulic cylinder into testing equipment. In the main part of this thesis there is described my own constructive proposal with numeric calculations in proper software. In enclosure there are all analytical calculations with productive drawings and an assembly drawing.

M.Tech. (Department of Civil Engineering, Faculty of Engineering and Technology), Vaal University of Technology / This research investigated the structural bond strength of GFRP rebars in concrete beams under dynamic loading with the aim to characterize the structural bond behaviour and evaluate the limitations of the GFRP rebars under dynamic loading. The dynamic loading in this study was set at 500 repeating cycles to simulate a more realistic dynamic loading scenario such as earthquake since most dynamic loading studies are carried under ten repeating cycles. The experimental work was divided into 2 main tests which were firstly, the tensile tests of the GFRP rebars in order to evaluate the tensile strength of the rebars and characterize their properties. Secondly, the flexural tests of GFRP and steel reinforced concrete beams in order to evaluate the bond strength of GFRP and steel rebars, to characterize the average bond strength of GFRP and steel reinforced concrete beams under dynamic loading and finally to compare the average bond strength of GFRP rebars to Steel rebars in both dynamic and static loadings. The tensile tests were carried out using a Universal Testing Machine (UTM) and the results of the tensile tests of the GFRP rebars showed that the average experimental tensile strength of GFRP rebars was only 56.65% of the nominal tensile strength provided on the supplier data sheet. As for flexural tests, they were carried out through a four-point bending test using a UTM in conjunction with a universal dynamic shaker to create the dynamic loading set up. Steel reinforced concrete beams were used as control beams during the tests and factors such as the tensile strength of the GFRP rebars, the slip of the rebars, the load-deflection relationship and the stress-strain relationship were investigated. The results of the tests showed that the tensile strength of the GFRP rebar is strongly proportional to the maximum beam load bearing capacity and the maximum stresses of GFRP reinforced concrete beams. The results also showed that the average bond strength of GFRP rebars in static loading (8.44 MPa) was only 80% of the average bond strength in dynamic loading (10.95 MPa). Moreover, the experimental work showed that the failure of GFRP reinforced concrete beams depicted large deflections (19 mm) and slips (5 mm to 12.5 mm) when compared to steel reinforced concrete beams (for which the maximum deflection was 9.66 mm at failure and slippage values of 2 mm to 10 mm). Based on that it could be stipulated that the tensile strength of GFRP rebars is one determinant factor to the bond strength behaviour of GFRP rebars in concrete. Hence, the structural bond behaviour of GFRP rebars could be well-defined if more studies were done on the bond behaviour of GFRP rebars in concrete beams under dynamic loading using another type of GFRP rebars that would consist of a relatively high tensile strength as compared to the ones used in this study and different surface texture.

The inclusion of electric vehicles in the automotive industry represents an opportunity for lubricating grease producers. Different speed, loads, and electric conditions are present in the bearings of the electric vehicles when compared with the conditions in a traditional internal combustion engine vehicle. Therefore, the development of new grease formulations is desired to overcome these, and other challenges introduced by this new technology. This project aims to compare two grease-thickener technologies through the installation, development, and validation of a novel high-speed bearing-grease test HSBT machine. This rig allows emulating the conditions present in the bearings of an electric vehicle. In this thesis, 6208 deep groove ball bearings were used to compare the mechanical performance of the greases. The comparative study of lithium complex and polypropylene greases was performed through the analysis of the frictional moment and self-induced temperature of the tested grease-bearing combinations. The results present the energy-saving potential of both greases and show the feasibility of using the HSBT machine as a grease testing machine. This project is the first step in an ambitious plan of enhancing e-mobility through grease research. It gives the input for future development of the machine and the creation of new standards for testing electric vehicle greases. / Införandet av elfordon i bilindustrin utgör en möjlighet för smörjfettproducenter. Olika hastigheter, belastningar och elektriska förhållanden är närvarande i de elektriska fordonens kullager i jämförelse med förhållandena i ett traditionellt förbränningsmotorfordon. Detta kräver utveckling av nya fetter som kan hantera de utmaningar som uppkommer med denna nya teknik. Detta projekt ämnar jämföra två fettförtjockningstekniker genom att installera, utveckla och validera en ny höghastighetslagermaskin (HSBT-maskin) för smörjfettstestning. Denna maskin möjliggör att förhållanden som finns i lagren hos ett elektriskt fordon kan efterliknas. I denna masteruppsats användes spårkullager med beteckningen 6208 för att jämföra smörjfettens mekaniska prestanda. I denna studie jämfördes litiumkomplex- och polypropenfetter genom att analysera friktionsmomentet och den självinducerade temperaturen för de testade kullagersmörjfettskombinationerna. Resultatet av studien visar energibesparingspotentialen för båda smörjfetterna och visar möjligheten att använda HSBT-maskinen för att testa smörjfetter. Detta projekt är det första steget i en ambitiös plan att förbättra e-mobilitet genom smörjfettsforskning. Studien ger indata för framtida utveckling av elektriska maskiner och bidrar till skapandet av nya standarder för testning av fetter för elektriska fordon.

In dieser Arbeit wird das Tragverhalten von Leichtbeton unter mehraxialer Druckbeanspruchung behandelt. Zu diesem Zweck wurden zahlreiche Versuche mit verschiedenen Hochleistungsleichtbetonen in einer Triaxial-Prüfmaschine durchgeführt. Als Leichtzuschlag wurde Blähton verwendet. Die hergestellten Betone können in Festigkeitsklassen zwischen LC 35/38 und LC 80/88 eingeordnet werden. Bei den Hauptversuchen wurden vor allem die Bruchbilder, die Bruchfestigkeiten und die Prüfkörperverformungen registriert und analysiert. Im Rahmen der Auswertung der Versuche werden die Einflüsse von Matrix und Art des Leichtzuschlages auf die Bruchwerte und auf das Ver-formungsverhalten der Leichtbetone herausgearbeitet. Parallelen und Unterschiede zu bekannten Forschungsergebnissen an Leichtbetonen und zu Beton mit Normalzuschlägen werden aufgezeigt. Für die mathematische Beschreibung der Bruchwerte werden Näherungsfunktionen für zweiaxiale und für dreiaxiale Druckspannungskombinationen vorgeschlagen. / In this research the behaviour of lightweight concrete under multiaxial compression was investigated. Therefore more than 500 single tests were performed in a triaxial testing machine. The high performance lightweight aggregate concretes can be classified in Strength classes between LC 35/38 and LC 80/88. The main focuses in the evaluation of the experiments were the crack pattern, the fracture strength and the deformations. Especially the influences of type of matrix and type of lightweight aggregate on the fracture values and on the deformation behaviour of lightweight were identified. Parallels and differences to known research on lightweight concretes and concrete with normal aggregates were identified. For the mathematical description of the ultimate loads approximations were proposed for biaxial and triaxial compressive stress combinations.

[pt] Nesta dissertação foram desenvolvidas técnicas de controle por aprendizado acelerado e Neuro-Fuzzy, aplicadas em um sistema servo-hidráulico para ensaio de fadiga. Este sistema tem o propósito de fazer ensaios em materiais para prever a resistência à fadiga dos materiais. O trabalho envolveu quatro etapas principais: levantamento bibliográfico, desenvolvimento de um controle por aprendizado acelerado, desenvolvimento de um controle por aprendizado Neuro-Fuzzy, e implementação experimental dos modelos de controle por aprendizado proposto em uma máquina de ensaios de materiais. A implementação do controle por aprendizado acelerado foi feita a partir do modelo de controle desenvolvido por Alva, com o objetivo de acelerar o processo de aprendizagem. Esta metodologia consiste em fazer um controle do tipo bang-bang, restringindo a servo-válvula a trabalhar sempre em seus limites extremos de operação, i.e., procurando mantê-la sempre completamente aberta em uma ou outra direção. Para manter a servo-válvula trabalhando em seus limites de seu funcionamento, os instantes ótimos para as reversões são obtidos pelo algoritmo de aprendizado, e armazenados em tabelas específicas para cada tipo de carregamento. Estes pontos de reversão dependem de diversos fatores, como a amplitude e carga média da solicitação, e são influenciados pela dinâmica do sistema. Na metodologia proposta, a lei de aprendizado inclui um termo de momentum que permite acelerar a aprendizagem dos valores das tabelas constantemente durante a execução dos testes, melhorando a resposta a cada evento. O desenvolvimento de um controle por aprendizado Neuro-Fuzzy foi motivado pela necessidade de ter um agente com a capacidade de aprendizado e armazenamento dos pontos ótimos de reversão. Este modelo de controle também consiste na implementação de um controle do tipo bang-bang, trabalhando com a servo-válvula sempre nos seus limites extremos de operação. O instante de reversão é determinado pelo sistema Neuro-Fuzzy, o qual tem como entradas a gama (dobro da amplitude) e o valor mínimo do carregamento solicitado. O processo de aprendizado é feito pelas atualizações dos pesos do sistema Neuro-Fuzzy, baseado nos erros obtidos durante a execução dos testes, melhorando a resposta do sistema a cada evento. A validação experimental dos modelos propostos é feita em uma máquina servohidráulica de ensaios de fadiga. Para este fim, o algoritmo de controle proposto foi implementado em tempo real em um módulo de controle CompactRIO da National Instruments. Os testes efetuados demonstraram a eficiência da metodologia proposta. / [en] In this thesis, accelerated learning and Neuro-Fuzzy control techniques were developed and applied to a servo-hydraulic system used in fatigue tests. This work involved four main stages: literature review, development of an accelerated learning control, development of a Neuro-Fuzzy control, and implementation of the learning control models into a fatigue testing machine. The accelerated learning control was implemented based on a learning control developed in previous works, introducing a faster learning law. Both learning control methodologies consist on implementing a bang-bang control, forcing the servovalve to always work in its operational limits. As the servo-valve works in its operational limits, the reversion points to achieve every peak or valley in the desired history are obtained by the learning algorithm, and stored in a specific table for each combination of minimum and mean load. The servo-valve reversion points depend on a few factors, such as alternate and mean loading components, while they are as well influenced by the system dynamics. In the proposed accelerated methodology, the learning law includes one momentum term that allows to speed up the learning process of the table cell values during the execution of the tests. The developed Neuro-Fuzzy control also consists on a bang-bang control, making the servo-valve work in its operational limits. However, here the instant of each reversion is determined by the Neuro-Fuzzy system, which has the load range and minimum load required as inputs. The learning process is made by the update of the Neuro-Fuzzy system weights, based on the errors obtained during the execution of the test.The experimental validation of the proposed models was made using a servo-hydraulic testing machine. The control algorithm was implemented in real time in a C-RIO computational system. The tests demonstrated the efficiency of the proposed methodology.

In dieser Arbeit wird das Tragverhalten von Leichtbeton unter mehraxialer Druckbeanspruchung behandelt. Zu diesem Zweck wurden zahlreiche Versuche mit verschiedenen Hochleistungsleichtbetonen in einer Triaxial-Prüfmaschine durchgeführt. Als Leichtzuschlag wurde Blähton verwendet. Die hergestellten Betone können in Festigkeitsklassen zwischen LC 35/38 und LC 80/88 eingeordnet werden. Bei den Hauptversuchen wurden vor allem die Bruchbilder, die Bruchfestigkeiten und die Prüfkörperverformungen registriert und analysiert. Im Rahmen der Auswertung der Versuche werden die Einflüsse von Matrix und Art des Leichtzuschlages auf die Bruchwerte und auf das Ver-formungsverhalten der Leichtbetone herausgearbeitet. Parallelen und Unterschiede zu bekannten Forschungsergebnissen an Leichtbetonen und zu Beton mit Normalzuschlägen werden aufgezeigt. Für die mathematische Beschreibung der Bruchwerte werden Näherungsfunktionen für zweiaxiale und für dreiaxiale Druckspannungskombinationen vorgeschlagen. / In this research the behaviour of lightweight concrete under multiaxial compression was investigated. Therefore more than 500 single tests were performed in a triaxial testing machine. The high performance lightweight aggregate concretes can be classified in Strength classes between LC 35/38 and LC 80/88. The main focuses in the evaluation of the experiments were the crack pattern, the fracture strength and the deformations. Especially the influences of type of matrix and type of lightweight aggregate on the fracture values and on the deformation behaviour of lightweight were identified. Parallels and differences to known research on lightweight concretes and concrete with normal aggregates were identified. For the mathematical description of the ultimate loads approximations were proposed for biaxial and triaxial compressive stress combinations.

В данной работе были рассмотрены различные испытательные машины, изучен принцип и особенности работы разрывной машины для статических испытаний металлов Р-10. Проведены расчеты геометрических параметров гидроцилиндров (основного рабочего и захватов), прочностной и расчет на устойчивость. Также, исходя из перечисленных расчетов подобран рабочий насос и среда – масло. Смоделированы детали модели в пакете программ SolidWorks, а в пакете MATLAB Simscape составлена сборка разрывной машины и добавлена система с гидроприводом. В результате исследования была получена имитационная модель статической разрывной машины для металлов, при помощи которой было проведено моделирование испытания на растяжение. Для этого был выбран образец стали известной марки с заранее определенными геометрическими параметрами. После чего к образцу были приложены различные усилия, и сняты показания удлинения образца. На основе этого был получен график. Затем с помощью данных усилие/перемещение и начальных геометрических параметров были рассчитаны пределы пропорциональности, текучести, прочности на основании которых и был определен материал образца. Данный пример демонстрирует правильность разработки подобных моделей в системе MATLAB, которые могут позволить провести детальные исследования процессов работы механизмов машины во время испытаний, в том числе оценить характеристики гидравлической системы разрывной испытательной машины. / In this dissertation, various testing machines were considered, the principle and features of the operation of a tensile testing machine for static testing of metals R-10 were studied. Calculations of the geometrical parameters of hydraulic cylinders (main working and grippers), strength and stability calculations were carried out. Also, based on the above calculations, a working pump and a medium - oil were selected. The details of the model were modeled in SolidWorks, and the tensile testing machine assembly was assembled in MATLAB Simscape and the hydraulic actuator system was added. As a result of the study, a simulation model of a static tensile testing machine for metals was obtained, with the help of which a simulation of a tensile test was carried out. For this, a sample of well-known brand steel with predetermined geometric parameters was selected. After that, various forces were applied to the sample, and indications of the elongation of the sample were taken. Based on this, a graph was obtained. Then, using the force / displacement data and the initial geometric parameters, the limits of proportionality, yield, strength were calculated, on the basis of which the sample material was determined. This example demonstrates the correctness of developing such models in MATLAB. They can make it possible to conduct detailed studies of the operation of the machine mechanisms during testing, including the evaluation of the characteristics of the hydraulic system of the tensile testing machine.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-08-08T13:44:54Z No. of bitstreams: 1 RÔMULO AUGUSTO VENTURA SILVA - TESE PPGCMat 2011..pdf: 4840398 bytes, checksum: 2eaeb4106f3f72d0bc93dcad5ae11213 (MD5) / Made available in DSpace on 2018-08-08T13:44:54Z (GMT). No. of bitstreams: 1 RÔMULO AUGUSTO VENTURA SILVA - TESE PPGCMat 2011..pdf: 4840398 bytes, checksum: 2eaeb4106f3f72d0bc93dcad5ae11213 (MD5) Previous issue date: 2011-07 / A avaliação correta das propriedades de um determinado material é fundamental para que o seu desempenho atenda a todas as expectativas para as quais ele foi projetado. No decorrer do desenvolvimento de argamassa expansiva para lavra de rochas ornamentais, verificou-se a deficiência de equipamentos que pudessem avaliar a pressão e a temperatura originada por esta argamassa durante o processo de expansão. Este trabalho descreve o projeto de desenvolvimento de um equipamento para este fim. O projeto foi desenvolvido utilizando tecnologia de microcontroladores, conversores analógico-digitais do tipo SAR (successive approximation register), célula de carga do tipo S, termopares do tipo K e termistores. Em todos os itens do projeto, utilizaram-se CAD (Computer Aided Design). O armazenamento dos dados obtidos se dá em cartão de memória SD e a comunicação através de barramento USB e serial, permitindo a operação na ausência de computadores nos mais diversos ambientes com a mais ampla conectividade. Além do equipamento em si, o programa embarcado no microcontrolador e o programa de computador, responsável pela aquisição e transferência dos dados também foi desenvolvido e testado, exibindo resultados dentro dos padrões desejados. / The correct evaluation of the properties of a material is essential so that their performance meets the expectations for which it was designed. During the development of expansive mortar for mining of ornamental rocks, there was a lack of equipment that could evaluate the pressure and temperature caused by the mortar during the expansion process. This paper describes a device for this purpose. The project was developed using microcontroller technology, analogue to digital converters of the type SAR (Successive Approximation register), load cell S-type, K type thermocouples and thermistors. In all items of the project, was used CAD (Computer Aided Design). The storage of data occurs in SD memory card and communication through USB and serial bus, allowing operation in the absence of computers in various environments with the broadest connectivity. Besides the equipment itself, the program embedded in the microcontroller and the program responsible for the purchase and transfer of data was also developed and tested, showing results within the desired standards.