Este trabalho apresenta uma análise minuciosa das solicitações de cisalhamento nas paredes de edifícios em alvenaria estrutural submetidos a ações horizontais. O estudo compreende a análise do comportamento global da estrutura, empregando-se diferentes modelagens numéricas para o sistema de contraventamento do edifício. Os modelos utilizados incluem a deformabilidade por cisalhamento das paredes e os efeitos provenientes da torção do edifício. Os resultados apresentados consistem em deslocamentos horizontais, distribuição dos esforços cortantes e momentos fletores entre as paredes, e análise das tensões de cisalhamento das paredes e lintéis. Avaliam-se, também, os diagramas de esforço cortante e momento fletor das paredes mais solicitadas. / This work presents a shear stress study of the shear walls of masonry buildings under lateral loads. The study consists of building overall structural behavior, with the use of different theoretical models for the lateral-load-resisting system of the building. The models include shear deformation and torsion effects. The results comprise horizontal displacement, shear force and bending moment distribution on shear walls, enhancing the shear stress verification of greater internal-forces values in walls and lintels. Shear force and bending moment diagrams related to the walls with the greater internal forces are also shown.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-08-15T14:41:50Z No. of bitstreams: 1 Clodomir Barros Pereira Junior.pdf: 3373410 bytes, checksum: 7b34e9beab048ca37a9eaaef8389a94d (MD5) / Made available in DSpace on 2016-08-15T14:41:50Z (GMT). No. of bitstreams: 1 Clodomir Barros Pereira Junior.pdf: 3373410 bytes, checksum: 7b34e9beab048ca37a9eaaef8389a94d (MD5) Previous issue date: 2015-08-18 / The study proposes actions to evaluate, on a pilot scale, the performance of biotech in the conservation and protection of slopes, in the neighborhood of Dois Irmãos in the city of Recife, Pernambuco, contributing to the development of a technology to be used in the conservation of the urban slopes, that meet the legal requirements and techniques aims to assess the soil shear resistance in different types of soil covers the experiment was composed of 21 plots, of which 16 were selected experimental plots consist of four types, which were subjected to four repetitions, which represented four types of coverages that may be adopted in the recovery of degraded areas. This work aimed to evaluate the shear strength in experimental plots with 2.0 m wide by 5.0 m in length, using different types of toppings: (1) sediment retainers on bare soil; (2) biomanta of sisal fiber; (3) grass Vetiver Vetiveria zizanioides L (Nash), randomized; (4) soil without vegetation cover. The chance to be verified is that different types of toppings and combinations contribute to maximize soil shear resistance, aiding in conservation and slope protection in municipal landfills. The products are based on the results obtained and noting that the typologies used in grassy coverage obtained more shear strength than bare soil. / O trabalho propõe ações para avaliar, em escala piloto, o desempenho de biotécnicas na conservação e proteção de taludes de aterros, no bairro de Dois Irmãos na Cidade de Recife, Pernambuco, contribuindo para o desenvolvimento de uma tecnologia a ser utilizada na conservação das encostas urbanas, que atendam às exigências legais e técnicas Tem como objetivo avaliar a resistência do solo ao cisalhamento em tipologias diferentes de coberturas de solo O experimento foi constituído de 21 parcelas, das quais foram selecionadas 16 parcelas experimentais constituídas de quatro tipologias, as quais foram submetidas a quatro repetições, que representaram quatro tipos de coberturas que podem vir a ser adotadas na recuperação de áreas degradadas. Este trabalho teve como objetivo avaliar a resistência ao cisalhamento em parcelas experimentais com 2,0 m de largura por 5,0 m de comprimento, utilizando diferentes tipos de coberturas: (1) retentores de sedimentos sobre solo desnudo; (2) biomanta de fibra de sisal; (3) capim Vetiver Vetiveria zizanioides L (Nash), casualizado; (4) solo desnudo, sem cobertura vegetal. A hipótese a ser verificada será a de que diferentes tipos de coberturas e combinações contribuem para maximizar a resistência do solo ao cisalhamento, auxiliando na conservação e proteção de taludes em aterros urbanos. Os produtos se basearam nos resultados obtidos e constatando-se que as tipologias que utilizaram cobertura em gramínea obtiveram mais resistência ao cisalhamento do que as de solo desnudo.

Orientador: Francisco Maugeri Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-05T17:05:43Z (GMT). No. of bitstreams: 1 YepezSilva-Santisteban_BernardoOnagar_D.pdf: 1839103 bytes, checksum: 44dfdd6f4dc2a025d2bcdbcf149d2ef1 (MD5) Previous issue date: 2006 / Doutorado / Doutor em Engenharia de Alimentos

La compréhension de la dynamique de la turbulence de paroi a déjà fait l'objet de nombreuses études expérimentales et numériques depuis des décennies. Le principal intérêt pratique de ces études tient au fait que la contrainte de cisaillement pariétale (et donc le frottement) est étroitement liée à la dynamique des structures à la proximité de la paroi. Les techniques expérimentales en mécanique des fluides ont également fait de grands progrès ces dernières années. Ce travail présente le développement d'une méthode expérimentale visant à fournir des mesures 3D-3C de l´écoulement dans la région de très proche paroi, en vue de mesurer la contrainte de cisaillement à la paroi avec une précision améliorée. Dans ce but, une technique originale de Vélocimétrie Holographique par Images de Particules a été mise au point. Les mesures sont effectuées dans un petit volume à proximité de la paroi dans la soufflerie au Laboratoire de Mécanique de Lille. Des mesures détaillées dans un de l’ordre de 1.5mm3 sont rendues possibles grâce l'utilisation d'un objectif de microscope pour l'agrandissement du champ objet. Les particules sont éclairées par le côté, la lumière diffusée a 90o se recombine avec l'onde de référence pour un enregistrement holographique en ligne de type Gabor. Une procédure d'étalonnage a été développée afin de relier l'espace de reconstruction de l’image holographique aux coordonnées dans le volume de mesure. L'analyse des résultats montre que les images de particules sont reconstruites avec une très bonne résolution axiale, ce qui conduit à penser que la configuration est bien adapté à cette type de mesure. Ces résultats montrent également qu’une optimisation et des ajustements sont nécessaires pour d'améliorer les résultats de suivi de particules / Continuously improving the understanding of wall turbulence dynamics has been the goal of many experimental and numerical studies for decades. The main practical aspect that makes this knowledge so crucial is the fact that the wall shear stress is closely related to the dynamics of the near-wall structures. Experimental techniques in fluid mechanics have also experienced a great amount of advances in recent years. The present work details the development of an experimental configuration aimed at providing 3D-3C flow measurements in the very near-wall region of a large wind tunnel facility, leading to the assessment of the wall shear stress with improved accuracy. With that goal, a technique known as Holographic Particle Image Velocimetry is used, and measurements are made in small volumes close to the wall in the wind tunnel at Laboratoire de Mécanique de Lille. Full measurements in volumes as small as 1.5mm3 are made possible with the use of a microscope objective for magnification of the object field. Particles are illuminated from the side and the 90o scattered field recombines with reference wave for holographic inline recording. A calibration procedure is performed in order to relate reconstruction space coordinates to real measurement volume coordinates. Analysis of resulting particle fields shows that particle images reconstruct with very good axial accuracy, leading to believe that the configuration is indeed suited for this type of measurement. However, some optimization and adjustments are needed in order to improve the particle tracking results

The stringing regulation on greenhouse gases emissions coupled with the rising fuel price and the growth in aviation transportation have imposed increasing demands on the aircraft industry to develop revolutionary technologies to meet such challenges. Methods of delaying flow separation on aircraft high lift systems have been sought which can lead to an increase in the aircraft performance and ultimately a reduction in aircraft operational costs and its impact on the environment. Synthetic jet actuators are a promising method of delivering flow control for aircraft applications due to their ability to inject momentum to an external flow without net mass flux and their potential in being integrated in MEMS through micro-fabrication with relative ease. It has been demonstrated in many laboratory experiments that synthetic jets are capable of delaying flow separation on aerodynamic bodies of various shapes. However, currently the operating conditions of synthetic jets are mostly chosen by trial-and-error, and thus the flow control effectiveness varies from one experiment to another. In order to deliver an effective flow separation control which achieves a desired control effect at minimum energy expenditure, a better understanding of the fluid mechanics of the behaviour of synthetic jets and the interaction between synthetic jets and a boundary layer are required. The aims of the present research were to achieve such a goal through a series of purposely designed numerical simulations. Firstly, synthetic jets issued from a circular orifice into quiescent air were studied to understand the effect of dimensionless parameters on the formation and the extent of roll-up of vortex rings. The computational results confirmed that the Stokes number determines the strength of vortex roll-up of a synthetic jet. Based on the computational results, a parameter map was produced in which three different operational regimes of synthetic jets were indentified and a criterion for vortex roll-up was also established. A circular synthetic jet issued into a zero-pressure-gradient laminar boundary layer was then investigated. The capability of FLUENT in modelling the key characteristics of synthetic jets was validated using experimental data. The formation and evolution of coherent structures produced by the interaction between synthetic jets and a boundary layer, as well as their near-wall effect in terms of the wall shear stress, were examined. A parameter map illustrating how the appearance of the vortical structures and their corresponding shear stress patterns vary as the synthetic jet operating condition changes was established. In addition, the increase in the wall shear stress relative to the jet-off case was calculated to evaluate their potential separation control effect.Finally, the study moved one step forward to investigate the flow separation control effect of an array of three circular synthetic jets issued into a laminar boundary layer which separates downstream on an inclined plate. The impact of synthetic jets on the boundary layer prior to separation and the extent of flow separation delay on the flap, at a range of synthetic jet operating conditions, were examined and the correlation between them was investigated. Furthermore, the optimal operating conditions for this synthetic jet array in the current study were identified by considering both the flow control effect and the actuator power consumption. The characteristics of the corresponding vortical structures were also examined.The findings from this work have produced some further insights of the behaviour and the interaction between synthetic jets and a boundary layer, which will be useful for ensuring an effective application of synthetic jets in practical settings.

In this work, we have developed user interactive capabilities that allow us to perform segmentation and manipulation of patient-specific geometries required for Computational Fluid Dynamics (CFD) studies, entirely in image domain and within a single platform of ‘IAFEMesh'. Within this toolkit we have added commonly required manipulation capabilities for performing CFD on segmented objects by utilizing libraries like ITK, VTK and KWWidgets. With the advent of these capabilities we can now manipulate a single patient specific image into a set of possible cases we seek to study; which is difficult to do in commercially available software like VMTK, Slicer, MITK etc. due to their limited manipulation capabilities. Levelset representation of the manipulated geometries can be simulated in our flow solver (SCIMITAR-3D) without creating any surface or volumetric mesh. This image-levelset-flow framework offers few advantages. 1) We don't need to deal with the problems associated with mesh quality, edge connectivity related to mesh models, 2) and manipulations like boolean operation result in smooth, physically realizable entities which is challanging in mesh domain. We have validated our image-levelset-flow setup with the known results from previous studies. We have modified the algorithm by Krissian et al. and implemented it for the segmentation of Type-A aortic dissection. Finally, we implemented these capabilities to study the hemodynamics in Type-A aortic dissection. Our image based framework is a first of its kind and the hemodynamic study of Type-A dissection too is first study onto the best of our knowledge.

Birds uniquely produce sound through a vocal organ known as a syrinx. The presence of wall shear stress acting on the airway cells of any organism will affect how airway cells develop and multiply. Unique features of avian airway geometry and breathing pattern might have contributed to the development of the syrinx. This thesis examines wall shear stress in the trachea and first bronchi of avian geometries using computational fluid dynamics. The computational fluid dynamic simulations underwent grid- and time-independence studies and were validated using particle image velocimetry. Parameters such as bird size, bronchial branching angle, and breathing waveform were examined to determine conditions that contributed to higher wall shear stress. Both simplified and CT scan-derived respiratory geometries were examined. Maximum wall shear stress for the simplified geometries was found to be highest during the inspiratory phase of breathing and was highest near the pessulus. Maximum wall shear stress in the CT scan-derived geometries was less phase-dependent and was highest near constrictions in the airway. Comparison between scanned and simplified geometry simulations revealed significant differences in wall shear stress magnitudes and flow features. If wall shear stress is found to be important in the development of the syrinx or the advantage of a syrinx, the thesis results are anticipated to aid in characterizing conditions that would have contributed to the development of the syrinx or advantages of syringeal vocal fold position over tracheal vocal fold position.

Endothelial cells form the lining of the walls of blood vessels and are continuously subjected to mechanical stimuli from the blood flow. Microtubule-organizing center (MTOC),<br>also known as centrosome is a structure found in eukaryotic cells close to the nucleus. MTOC relocates relative to the nucleus when endothelial cells are exposed to shear stress which determines their polarization, thus it plays a critical role in cell migration and wound healing. The nuclear lamina, a mesh-like network that lies underneath the nuclear membrane, is composed of lamins, type V intermediate filament proteins. Mutations in LMNA gene that encodes A-type lamins cause the production of a mutant form of lamin A called progerin and leads to a rare premature aging disease known as Hutchinson-Gilford Progeria Syndrome<br><div>(HGPS). The goal of this study is to investigate how fluid flow affects the cytoskeleton of endothelial cells.</div><div><br></div>This thesis consists of two main sections; computational mechanical modeling and laboratory experimental work. The mechanical model was implemented using Ansys Workbench software as a tensegrity-based cellular model in order to simulate the state of an endothelial cell under the effects of induced shear stress from the blood fluid flow. This tensegrity-based cellular model - composed of a plasma membrane, cytoplasm, nucleus, microtubules, and<br><div>actin filaments - aims to understand the effects of the fluid flow on the mechanics of the cytoskeleton. In addition, the laboratory experiments conducted in this study examined the MTOC-nuclear orientation of endothelial cells under shear stress with the presence of wound healing. Wild-type lamin A and progerin-expressing BAECs were studied under static and sheared conditions.</div><div><br></div><div> Moreover, a custom MATLAB code was utilized to measure the MTOC-nuclear orientation</div>angle and classification. Results demonstrate that shear stress leads to different responses of the MTOC orientation between the wild-type and progerin-expressing cells around the vertical wound edge. Future directions for this study involve additional experimental work together with the improved simulation results to confirm the MTOC orientation<br>relative to the nucleus under shear stress.

Subclinical atherosclerosis is an important area of research to evaluate stroke risk and predict localization of plaque. The current methods for detecting atherosclerosis risk are insufficient because it is based on The Framingham Risk Score and carotid intima media thickness, therefore an engineering detection model based on quantifiable data is needed. Laminar and turbulent flow, dictated by Reynolds number and relative roughness, was modeled through the carotid artery bifurcation to compare shear stress and shear rate. Computer-aided design and fluid flow software were used to model hemodynamics through the carotid artery. Data from the model was derived from governing equations programmed in COMSOL for both laminar and turbulent flow. A carotid artery model is accurate enough to describe how relative roughness, flow profiles, and shear rate can be a good prediction of subclinical atherosclerosis.

The aim of this labor is to optimize the vortex pump. When this pump should find application on the field of health like human heart for extracorporeal circulation. We will deal with the analysis of shear stress in the pump and its size of it and consider the use nonwetting surfaces to reduce the shear stress values. All our analysis will be made by CFD calculations.