For efficient transportation in either trains, busses or passenger cars, rolling elements such as wheels, tyres, bearings and transmission elements are fundamental. The energy efficiency and the generation of noise and vibrations in rolling contacts depend on the surface roughness of contacting bodies. In order to optimize the surfaces of rolling elements, prediction of its impact on the dynamic response from rolling excitation is required. A computationally efficient method to include surface roughness in the modelling of rolling contacts is presented. More specifically, nonlinear effects on the contact force due to the threedimensional shape and roughness of the contacting surfaces are introduced in a moving point force formulation. As a consequence of the point force approximation follows the assumption that any dynamic wave motion within the contact area is negligible.The rolling contact force is nonlinear due to a varying relative displacement between contacting bodies and is therefore referred to as state-dependent. A study case for the state-dependent method consisting of a steel ball rolling on a steel beam showed good agreement between numerical predictions and measured beam vibrations. Furthermore, an application to the wheel-rail interaction show that roughness-induced contact nonlinearities have a significant impact on the dynamic response caused by rolling excitation. / <p>QC 20141103</p> / ECO2 Vehicle Design

Different wave power technologies are in development around the world in different stages of prototype testing. So far only a few devices have been deployed offshore at full scale for extended periods of time. Little data is published about how these different devices perform. This thesis presents results from experiments with the full-scale offshore wave energy converters at the Lysekil research site on the Swedish west coast. The theories, experiments, measurements, performance evaluations and developments of the submerged transmission in the direct driven permanent magnet linear generator are in focus. The reciprocating submerged transmission fulfills the purpose of transmitting the absorbed mechanical wave energy through the capsule wall into the generator, while preventing the seawater from entering the capsule and reducing the life time of the converter. A measuring system with seven laser triangulation sensors has been developed to measure small relative displacements between piston rod and seal housing in the submerged transmission with excellent accuracy for the purpose of evaluating both functional behavior and successive wear in-situ. A method for calculating relative tilt angles, azimuth angles, differential tilt angles, and successive wear in the submerged transmission has been developed. Additional sensors systems have been installed in the converter enabling correlation and a thorough investigation into the operating conditions of the transmission and the converter. The thesis presents unique results from the measurements. A data acquisition system transmits the signals from the converter on the seabed to an onshore measuring station. Results are presented in time-, frequency- and the time-frequency domain. The results have given important information for further development of the submerged transmission, which is important to the survivability of the system. The thesis describes the status of research, and is a step that may influence future designs of wave energy devices for reaching survivability and a cost-effective renewable energy system. / <p>Published is a preprint version of the full text and should be combined by the errata.</p> / The Lysekil Wave Power Project

Orientadora: Prof.ª Dr.ª Léia Bernardi Bagesteiro / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Biomédica, 2015. / A osteotomia proximal da tibia (OPT) com cunha medial aberta e uma intervencao cirurgica utilizada para o tratamento de osteoartrite no condilo medial. Basicamente consiste na realizacao de um corte parcial da tibia e na abertura em formato de cunha em um angulo pre-determinado. Apos a abertura e necessaria a fixacao de um implante ortopedico. Os dispositivos ortopedicos utilizados para estabilizar a fratura devem suportar as cargas biomecanicas e gerar um ambiente mecanico capaz de permitir a consolidacao ossea. O objetivo deste estudo e analisar as tensoes de um novo implante (NPO) para osteotomia, previamente projetado pelo autor e colaboradores, bem como os deslocamentos relativos da cunha apos a aplicacao de cargas estaticas, atraves do metodo dos elementos finitos. Baseados em imagens medicas geradas a partir de tomografias computadorizadas, tres modelos distintos de elementos finitos da tibia com abertura em cunha foram simulados e fixados com: (1) uma nova placa para osteotomia (NPO), (2) uma placa gTh reta (PTR) e (3) uma placa gTh curva (PTC). Em cada avaliacao foram consideradas duas condicoes de carga em pos-operatorio: (1) primeira semana e (2) sexta semana. A tensao maxima observada na NPO (362,62 MPa) foi 57,08% maior que a PTR (230,85 MPa) e 23,47% (293,70 MPa) maior que a PTC. O deslocamento da configuracao NPO (1,37 mm) foi similar a tibia intacta e a PTC e a PTR, que apresentaram deslocamentos do tecido osseo de 1,35 mm e 1,30 mm, respectivamente. Para o caso da primeira semana do pos-operatorio a NPO apresentou movimento relativo interfragmentar (MRI) axial minimo e maximo de 169,58 ¿Êm e 218,14 ¿Êm, respectivamente. E MRI cisalhante minimo e maximo de 1,21 ¿Êm e 0,96 ¿Êm, respectivamente. Estes valores foram inferiores e superiores a 0,2 mm. Segundo PLECKO et al. (2013) valores acima de 0,2 mm aumentam a proliferacao de calo ossificado. No caso da sexta semana o MRI axial minimo da cunha foi de 165,20 ¿Êm e o maximo de 284,01 ¿Êm. Enquanto que o MRI cisalhante minimo foi de 47,52 ¿Êm e o maximo de 50,82 ¿Êm. A PTR apresentou valores de MRI axial entre 153,39 ¿Êm e 233,68 ¿Êm na primeira semana e 136,92 ¿Êm e 314,47 ¿Êm na sexta semana. E MRI de cisalhamento entre 1,12 ¿Êm e 1,95 ¿Êm na primeira semana e 87,49 ¿Êm e 92,89 ¿Êm na sexta semana. A PTC apresentou valores de MRI axial entre 158,92 ¿Êm e 233,70 ¿Êm (primeira semana) e 154,33 ¿Êm e 310,31 ¿Êm (sexta semana). E MRI cisalhante entre 0,94 ¿Êm e 1,66 ¿Êm (primeira semana) e 77,67 ¿Êm e 78,40 ¿Êm (sexta semana). Portanto, a analise valida a utilizacao do novo implante para osteotomia proximal da tibia e sugere a reducao de material nas regioes de baixa tensao equivalente de von Mises. Todos os implantes apresentaram valores de tensoes menores que o limite de escoamento da liga de titanio (Ti-6Al-4V) e permitiram o deslocamento da tibia com osteotomia proximo ao deslocamento da tibia intacta. A cunha apresentou regioes de micromovimento e microdeformacao que permitem a cicatrizacao ossea em ambas condicoes de carga. / IOpen wedge high tibial osteomy is a surgical intervention used to treat medial compartment osteoarthritis. The technique consists of tibial partial cut and an opening wedge with a pre-defined angle. Once opened, the orthopedic implant¿s fixation is required. The orthopedic devices used to stabilize the fracture should support the biomechanical loads and create an optimal mechanical environment to allow the fracture healing. The aim of this study is to analyze the stress level and displacements for the new implant of the osteotomy wedge under static loads using the finite element method. Using CT-based images, three tibia¿s distinct finite element models with open wedge were simulated and fixed: (1) the new implant osteotomy, (2) a straight T plate (STP) and (3) a curved T plate (CTP). On each evaluation two load conditions were considered: (1) the first week post-operative and (2) the sixth week post-operative. The maximum stress observed for the new implant (362.62MPa) was 57.08% higher than STP (230.85MPa) and 23.47% higher than CTP (293.70MPa). The highest displacement of the bone tissue was showed by the new implant (1.37mm), follow by STP (1.35mm) and CTP (1.30mm). For the first week condition, the wedge with the new implant showed minimum and maximum axial interfragmentary relative micromotion (IRM) of 169.58ìm and 218.14ìm. And shear IRM minimum and maximum of 1.21ìm e 0.96ìm, respectively. These values were inferior and superior to 0.2 mm. According to PLECKO et al. (2013), values larger than 0.2 mm increases the proliferation of callus ossified. For the sixth week, the minimum and maximum axial IRM were 165.20ìm and 284.01ìm. And shear IRM minimum and maximum of 47.52ìm and 50.82ìm, respectively. The STP showed IRM between 153.39ìm and 233.68ìm in the first week, and 136.92ìm and 314.47ìm for the sixth week. And shear IRM between 1.12ìm e 1.95ìm in the first week and 87.49ìm and 92.89ìm in the sixth week. The CTP showed IRM between 158.92ìm and 233.70ìm (first week), and 154.33ìm and 310.31ìm (sixth week). And shear IRM between 0.94ìm e 1.66ìm (first week) and 77.67ìm and 78.40ìm in the sixth week. Therefore, the analysis validates the use of the new implant for proximal tibial osteotomy and suggests the material's reduce in the regions with lower von Mises equivalent stress. All implants showed stress levels lower than the yield strength of the titanium alloy (Ti-6Al-4V) and the displacement of the fractured tibia was similar to the intact tibia. The wedge showed regions of micromotion (mm) and strain (%) that allowed the fracture healing in both loads conditions.

This thesis deals with design of optimal parameters of a relative displacement sensor, working on the electrodynamics principle. The sensor is based on the voltage induction to the coil placed in changing magnetic field. Thesis is divided into three parts: introductory, theoretical and practical. The introductory part provides basic relationships between displacement, velocity and acceleration sensors. The theoretical part contains physical concepts and describes relationships necessary for calculations and creating a model of permanent magnet in COMSOL Multiphysics. In thesis further presents patent research of electrodynamic sensors. The practical part describes the creation of the permanent magnet model and the subsequent calculation of the induced voltage in the coil in Matlab. A description of laboratory measurements follows, presenting the final comparison of the simulation and measurement results. There were found some differences, which might have been caused by incorrect calculation of the induced voltage. The final part of the thesis presents general recommendations for the design of sensor, resulting from simulations and measurements.

The thesis is divided into two main parts. In the first theoretical part is described the problems of shrinking including a comparison of Czech standard and Model Code 2010, Vol. 1. The second practical part of the master`s thesis is focused on the numerical analysis shrinkage primarily on the initial stage of this process. The experimentally obtained data are set approximations of the relative deformation using ShrCeC. Subsequently the numerical simulation of shrinkage of selected silicate specimens using a computer applications SpatiDist and FyDiK 2D. The real test specimens are modelled as two-component composite consisting of cement paste and aggregates. The result is a parametric study takes into account the influence of type and size of grain aggregate.