The movement and control of the vocal folds within the laryngeal cavity enables three crucial physiological functions: 1) allowing respiration by opening, 2) aiding in airway protection by closing, and 3) regulating sound production during phonation. Although treatment options have improved, many of the estimated 7.5 million individuals in the United States who are annually affected by voice-related disorders still face serious challenges related to dysphonia and dysphagia. The need for improved voice-disorder treatments has motivated the work presented in this dissertation which focuses on modeling and manufacturing the vocal folds and aims to answer three main questions: 1) what are the mechanical properties of the vocal folds and how do they change across the full vocal range? 2) how do those properties influence the dynamic behavior of the tissue? and 3) can we manufacture a synthetic vocal fold model that exhibits a desired and controllable dynamic behavior? First, the elastic properties of sixteen porcine vocal folds were evaluated through uniaxial tensile tests on a custom built experimental setup. Stress-strain data was analyzed using an optimization method to yield continuous model parameters which described the linear and nonlinear elastic regions as well as transition points between those regions. Next, the impact of the vocal fold elastic properties on the frequencies of vibration was evaluated through dynamic tests on excised porcine larynges. Sound data was analyzed via a spectrogram and through the use of fast Fourier transforms to study changes in the frequency of vibration while the vocal folds were stretched. Additionally, a mathematical aeroelastic model of phonation was implemented to further evaluate the changing elastic properties on vocal fold dynamics. Next, eight synthetic vocal fold models were created, each with varying mechanical properties and a geometry based on reported anatomical measurements of porcine vocal folds. The synthetic models were then dynamically tested to further study the impact of changes in mechanical properties on the dynamic behavior of the synthetic vocal folds. / Doctor of Philosophy / The movement and control of the vocal folds within the voice-box enables three crucial physiological functions: 1) allowing respiration by opening, 2) aiding in airway protection and swallowing by closing, and 3) regulating sound production during vocalization. Although treatment options have improved, many of the estimated 7.5 million individuals in the United States who are annually affected by voice-related disorders still face serious challenges related to speech production and swallowing which often results in significant detrimental impacts to quality of life. The need for improved treatments is most easily observed in the evaluation of treatment options following a total laryngectomy, which is a procedure where the entire voice-box is removed often due to cancer. Following a laryngectomy, all three of the vital functions of the vocal folds are immediately impacted as patients adjust to breathing through and protecting a redirected airway and are forced to use alternative methods of speech production which often result in monotone or robotic-sounding speech. The need for improved voice-disorder treatments has motivated the work presented in this dissertation which focuses on modeling and manufacturing the vocal folds and aims to answer three main questions: 1) what are the mechanical properties of the vocal folds? 2) how do those properties influence the dynamic behavior of the tissue during sound production? and 3) can we manufacture synthetic vocal folds that produce a desired and controllable dynamic behavior? Sixteen porcine vocal fold samples were mechanical tested to evaluate the elastic properties of the tissue. Next, porcine voice-box samples were experimentally tested in a way that simulated sound production by subjecting the samples to a heated and humidified air flow, similar to the air flow conditions coming out of the lungs. In this way, the relationship between the tissue properties and the frequencies of sound was investigated. Lastly, the synthetic vocal fold samples were evaluated using a similar experimental protocol to further investigate the impact of changing structural properties on the dynamics of the vocal folds during sound production.

Medições realizadas em edifícios altos, em escala real, têm mostrado que o carregamento devido à ação do vento pode causar importantes efeitos de torção. A atual tendência de construção de prédios com formas e sistemas estruturais mais complexos promove a acentuação das excentricidades entre o centro de massa, centro elástico e o ponto de aplicação instantânea de forças aerodinâmicas. Soma-se a isso o fato de os edifícios altos modernos estarem se tornando cada vez mais esbeltos e leves, o que baixa a velocidade (do vento) de disparo de fenômenos como galope e drapejamento torcional, fazendo com que esta velocidade se aproxime cada vez mais das velocidades do vento consideradas nos projetos. Frente a isso, os efeitos dinâmicos, tanto de flexão como de torção, induzidos pelo vento em edifícios altos representam uma importante consideração nos projetos de estruturas modernas. Os métodos analíticos para determinação da resposta de edifícios altos submetidos à ação do vento, hoje disponíveis, não levam a resultados satisfatórios em casos de geometrias não regulares, bem como não contemplam efeitos torsionais. Seu uso também não é recomendado no caso de estruturas muito flexíveis, cujo movimento afeta as forças aerodinâmicas que nelas atuam. Nessas situações, a melhor opção para os engenheiros é um estudo mais detalhado dos efeitos do vento sobre a estrutura, através de ensaios de modelos em escala reduzida em túneis de vento, que simulem as características do vento natural. O objetivo deste trabalho é o desenvolvimento de um mecanismo que permita a obtenção da resposta de edifícios altos frente à ação do vento, a partir de ensaios em túnel de vento com modelos em escala reduzida. Busca-se determinar a resposta em termos de suas componentes médias e flutuantes. Admite-se que a parcela dinâmica contempla os dois modos fundamentais de vibração livre em flexão, ortogonais entre si e aproximados de forma linear, e o primeiro modo de torção, aproximado de forma constante. As simplificações adotadas permitem que os modelos tenham baixa complexidade de projeto e construção, diminuindo, assim, o custo da modelagem e tornando o processo experimental mais ágil. Para validar os resultados obtidos com a utilização do mecanismo desenvolvido foram realizados ensaios em escala reduzida do CAARC Standard Tall Building, edifício alto tomado como padrão para calibração de técnicas de modelagem aeroelástica, no Túnel de Vento Professor Joaquim Blessmann, da Universidade Federal do Rio Grande do Sul. Os resultados obtidos foram comparados com os valores publicados por outros pesquisadores e com resultados determinados a partir de ensaios de medidas de pressões em alta freqüência. A coerência entre os valores comparados permitiu concluir que o equipamento simula satisfatoriamente o comportamento dinâmico de edifícios altos submetidos à ação do vento, mesmo perante fenômenos aeroelásticos, como a ressonância por desprendimento alternado de vórtices. A partir dos resultados verificou-se também a importância dos efeitos dinâmicos de torção induzidos pela ação do vento, e a necessidade de que sejam apropriadamente considerados nos projetos / Measurements performed in full-scale high rise buildings have shown that wind loading may cause important torsional effects. The current trend of building construction, with new shapes and complex structural systems promotes an increase in the distances (eccentricities) among the center of mass, elastic center and the instantaneous point of application of the resulting wind loads. Furthermore, modern tall buildings are becoming increasingly light and slender, diminishing the trigger wind speed of some phenomena such as galloping and torsional flutter, bringing these velocities closer to the design wind speeds. Therefore, wind induced bending and torsional dynamic effects in tall buildings play an important role in the design of modern structures. The current analytical methods for the response determination of tall buildings under wind loading do not lead to reliable results for the non regular building shapes, as well as do not consider torsional effects. Also, its use is not recommended for the case of very flexible structures, where the structure´s own motion may affect the aerodynamic forces acting on it. In these situations, the best option for engineers is a more detailed study of the wind effects, through boundary layer wind tunnels. The aim of this study is the development of a device that allows the determination of the response of tall buildings under wind loading, through wind tunnel tests with reduced scale models. The goal is the determination of the responses in terms of its mean and fluctuating components. It is assumed that the dynamic parcel contemplates the two fundamental bending modes of vibration, orthogonal and linear, as well as the torsional mode, which is assumed constant along the height. The adopted simplifications allow for a low complexity in the process of model design and construction as well as for a very low modeling cost, making more efficient the whole testing process. To validate the device, tests were performed with a reduced scale model of the CAARC Standard Tall Building, which is taken as a standard for the calibration of aeroelastic modeling techniques, in Prof. Joaquim Blessmann boundary layer wind tunnel of the Federal University of Rio Grande do Sul. The obtained results were compared with other researchers' values as well as with results obtained from pressure measurements, in a rigid model. The agreement among the compared values allows the conclusion that the device simulates satisfactorily well the dynamic behaviour of high rise buildings under wind loading, even for aeroelastic phenomena such as the resonance due to vortex shedding. It was also verified the importance of the wind induced torsional effects and the need for its proper consideration in the design process.

Medições realizadas em edifícios altos, em escala real, têm mostrado que o carregamento devido à ação do vento pode causar importantes efeitos de torção. A atual tendência de construção de prédios com formas e sistemas estruturais mais complexos promove a acentuação das excentricidades entre o centro de massa, centro elástico e o ponto de aplicação instantânea de forças aerodinâmicas. Soma-se a isso o fato de os edifícios altos modernos estarem se tornando cada vez mais esbeltos e leves, o que baixa a velocidade (do vento) de disparo de fenômenos como galope e drapejamento torcional, fazendo com que esta velocidade se aproxime cada vez mais das velocidades do vento consideradas nos projetos. Frente a isso, os efeitos dinâmicos, tanto de flexão como de torção, induzidos pelo vento em edifícios altos representam uma importante consideração nos projetos de estruturas modernas. Os métodos analíticos para determinação da resposta de edifícios altos submetidos à ação do vento, hoje disponíveis, não levam a resultados satisfatórios em casos de geometrias não regulares, bem como não contemplam efeitos torsionais. Seu uso também não é recomendado no caso de estruturas muito flexíveis, cujo movimento afeta as forças aerodinâmicas que nelas atuam. Nessas situações, a melhor opção para os engenheiros é um estudo mais detalhado dos efeitos do vento sobre a estrutura, através de ensaios de modelos em escala reduzida em túneis de vento, que simulem as características do vento natural. O objetivo deste trabalho é o desenvolvimento de um mecanismo que permita a obtenção da resposta de edifícios altos frente à ação do vento, a partir de ensaios em túnel de vento com modelos em escala reduzida. Busca-se determinar a resposta em termos de suas componentes médias e flutuantes. Admite-se que a parcela dinâmica contempla os dois modos fundamentais de vibração livre em flexão, ortogonais entre si e aproximados de forma linear, e o primeiro modo de torção, aproximado de forma constante. As simplificações adotadas permitem que os modelos tenham baixa complexidade de projeto e construção, diminuindo, assim, o custo da modelagem e tornando o processo experimental mais ágil. Para validar os resultados obtidos com a utilização do mecanismo desenvolvido foram realizados ensaios em escala reduzida do CAARC Standard Tall Building, edifício alto tomado como padrão para calibração de técnicas de modelagem aeroelástica, no Túnel de Vento Professor Joaquim Blessmann, da Universidade Federal do Rio Grande do Sul. Os resultados obtidos foram comparados com os valores publicados por outros pesquisadores e com resultados determinados a partir de ensaios de medidas de pressões em alta freqüência. A coerência entre os valores comparados permitiu concluir que o equipamento simula satisfatoriamente o comportamento dinâmico de edifícios altos submetidos à ação do vento, mesmo perante fenômenos aeroelásticos, como a ressonância por desprendimento alternado de vórtices. A partir dos resultados verificou-se também a importância dos efeitos dinâmicos de torção induzidos pela ação do vento, e a necessidade de que sejam apropriadamente considerados nos projetos / Measurements performed in full-scale high rise buildings have shown that wind loading may cause important torsional effects. The current trend of building construction, with new shapes and complex structural systems promotes an increase in the distances (eccentricities) among the center of mass, elastic center and the instantaneous point of application of the resulting wind loads. Furthermore, modern tall buildings are becoming increasingly light and slender, diminishing the trigger wind speed of some phenomena such as galloping and torsional flutter, bringing these velocities closer to the design wind speeds. Therefore, wind induced bending and torsional dynamic effects in tall buildings play an important role in the design of modern structures. The current analytical methods for the response determination of tall buildings under wind loading do not lead to reliable results for the non regular building shapes, as well as do not consider torsional effects. Also, its use is not recommended for the case of very flexible structures, where the structure´s own motion may affect the aerodynamic forces acting on it. In these situations, the best option for engineers is a more detailed study of the wind effects, through boundary layer wind tunnels. The aim of this study is the development of a device that allows the determination of the response of tall buildings under wind loading, through wind tunnel tests with reduced scale models. The goal is the determination of the responses in terms of its mean and fluctuating components. It is assumed that the dynamic parcel contemplates the two fundamental bending modes of vibration, orthogonal and linear, as well as the torsional mode, which is assumed constant along the height. The adopted simplifications allow for a low complexity in the process of model design and construction as well as for a very low modeling cost, making more efficient the whole testing process. To validate the device, tests were performed with a reduced scale model of the CAARC Standard Tall Building, which is taken as a standard for the calibration of aeroelastic modeling techniques, in Prof. Joaquim Blessmann boundary layer wind tunnel of the Federal University of Rio Grande do Sul. The obtained results were compared with other researchers' values as well as with results obtained from pressure measurements, in a rigid model. The agreement among the compared values allows the conclusion that the device simulates satisfactorily well the dynamic behaviour of high rise buildings under wind loading, even for aeroelastic phenomena such as the resonance due to vortex shedding. It was also verified the importance of the wind induced torsional effects and the need for its proper consideration in the design process.

Medições realizadas em edifícios altos, em escala real, têm mostrado que o carregamento devido à ação do vento pode causar importantes efeitos de torção. A atual tendência de construção de prédios com formas e sistemas estruturais mais complexos promove a acentuação das excentricidades entre o centro de massa, centro elástico e o ponto de aplicação instantânea de forças aerodinâmicas. Soma-se a isso o fato de os edifícios altos modernos estarem se tornando cada vez mais esbeltos e leves, o que baixa a velocidade (do vento) de disparo de fenômenos como galope e drapejamento torcional, fazendo com que esta velocidade se aproxime cada vez mais das velocidades do vento consideradas nos projetos. Frente a isso, os efeitos dinâmicos, tanto de flexão como de torção, induzidos pelo vento em edifícios altos representam uma importante consideração nos projetos de estruturas modernas. Os métodos analíticos para determinação da resposta de edifícios altos submetidos à ação do vento, hoje disponíveis, não levam a resultados satisfatórios em casos de geometrias não regulares, bem como não contemplam efeitos torsionais. Seu uso também não é recomendado no caso de estruturas muito flexíveis, cujo movimento afeta as forças aerodinâmicas que nelas atuam. Nessas situações, a melhor opção para os engenheiros é um estudo mais detalhado dos efeitos do vento sobre a estrutura, através de ensaios de modelos em escala reduzida em túneis de vento, que simulem as características do vento natural. O objetivo deste trabalho é o desenvolvimento de um mecanismo que permita a obtenção da resposta de edifícios altos frente à ação do vento, a partir de ensaios em túnel de vento com modelos em escala reduzida. Busca-se determinar a resposta em termos de suas componentes médias e flutuantes. Admite-se que a parcela dinâmica contempla os dois modos fundamentais de vibração livre em flexão, ortogonais entre si e aproximados de forma linear, e o primeiro modo de torção, aproximado de forma constante. As simplificações adotadas permitem que os modelos tenham baixa complexidade de projeto e construção, diminuindo, assim, o custo da modelagem e tornando o processo experimental mais ágil. Para validar os resultados obtidos com a utilização do mecanismo desenvolvido foram realizados ensaios em escala reduzida do CAARC Standard Tall Building, edifício alto tomado como padrão para calibração de técnicas de modelagem aeroelástica, no Túnel de Vento Professor Joaquim Blessmann, da Universidade Federal do Rio Grande do Sul. Os resultados obtidos foram comparados com os valores publicados por outros pesquisadores e com resultados determinados a partir de ensaios de medidas de pressões em alta freqüência. A coerência entre os valores comparados permitiu concluir que o equipamento simula satisfatoriamente o comportamento dinâmico de edifícios altos submetidos à ação do vento, mesmo perante fenômenos aeroelásticos, como a ressonância por desprendimento alternado de vórtices. A partir dos resultados verificou-se também a importância dos efeitos dinâmicos de torção induzidos pela ação do vento, e a necessidade de que sejam apropriadamente considerados nos projetos / Measurements performed in full-scale high rise buildings have shown that wind loading may cause important torsional effects. The current trend of building construction, with new shapes and complex structural systems promotes an increase in the distances (eccentricities) among the center of mass, elastic center and the instantaneous point of application of the resulting wind loads. Furthermore, modern tall buildings are becoming increasingly light and slender, diminishing the trigger wind speed of some phenomena such as galloping and torsional flutter, bringing these velocities closer to the design wind speeds. Therefore, wind induced bending and torsional dynamic effects in tall buildings play an important role in the design of modern structures. The current analytical methods for the response determination of tall buildings under wind loading do not lead to reliable results for the non regular building shapes, as well as do not consider torsional effects. Also, its use is not recommended for the case of very flexible structures, where the structure´s own motion may affect the aerodynamic forces acting on it. In these situations, the best option for engineers is a more detailed study of the wind effects, through boundary layer wind tunnels. The aim of this study is the development of a device that allows the determination of the response of tall buildings under wind loading, through wind tunnel tests with reduced scale models. The goal is the determination of the responses in terms of its mean and fluctuating components. It is assumed that the dynamic parcel contemplates the two fundamental bending modes of vibration, orthogonal and linear, as well as the torsional mode, which is assumed constant along the height. The adopted simplifications allow for a low complexity in the process of model design and construction as well as for a very low modeling cost, making more efficient the whole testing process. To validate the device, tests were performed with a reduced scale model of the CAARC Standard Tall Building, which is taken as a standard for the calibration of aeroelastic modeling techniques, in Prof. Joaquim Blessmann boundary layer wind tunnel of the Federal University of Rio Grande do Sul. The obtained results were compared with other researchers' values as well as with results obtained from pressure measurements, in a rigid model. The agreement among the compared values allows the conclusion that the device simulates satisfactorily well the dynamic behaviour of high rise buildings under wind loading, even for aeroelastic phenomena such as the resonance due to vortex shedding. It was also verified the importance of the wind induced torsional effects and the need for its proper consideration in the design process.

Incorporating uncertainties in the aeroelastic analysis increases the confidence levels of computational predictions and reduces the need for validation with experimental or flight test data. Helicopter rotor blades, which play a dominant role in the overall vehicle performance, are routinely made of composites. The material properties of composites are uncertain because of the variations in manufacturing process and other effects while in service, maintenance and storage. Though nominal values are listed, they are seldom accurate. In this thesis, the effect of uncertainty in composite material properties on the computational predictions of cross-sectional properties, natural frequencies, blade tip deflections, vibratory loads and aeroelastic stability of a four-bladed composite helicopter rotor is studied. The effect of material uncertainty is studied with the composite rotor blades modeled as components of soft-inplane as well as stiff-inplane hingeless helicopter rotors. Aeroelastic analysis based on finite elements in space and time is used to evaluate the helicopter rotor blade response in hover and forward flight. Uncertainty analysis is performed with direct Monte Carlo simulations based on a sufficient number of random samples of material properties. It is found that the cross-sectional stiffness parameters and natural frequencies of rotor blades show considerable scatter from their baseline predictions. The uncertainty impact on the rotating natural frequencies depends on the level of centrifugal stiffening of each mode. The propagation of material uncertainty into aeroelastic response causes large deviations from the baseline predictions. The magnitudes of 4/rev vibratory loads show deviations of 10 to 600 percent from their baseline predictions. The aeroelastic stability in hover and forward flight conditions also show considerable uncertainty in the predictions. In addition to the effects of material uncertainty, various factors influencing the propagation of material uncertainty are studied with the first-order based reliability methods. The numerical results have shown the need to consider the uncertainties in the helicopter aeroelastic analysis for reliable computational predictions. Uncertainty quantification using direct Monte Carlo simulation is accurate but computationally expensive. The application of response surface methodologies to reduce the computational cost of uncertainty analysis is studied. Response surface approximations of aeroelastic outputs are developed in terms of the composite material properties. Monte Carlo simulations are then performed using these computationally less expensive response surface models. The results of this study show that the metamodeling techniques can effectively reduce the computational cost of uncertainty analysis of composite rotor blades. In the last part of the thesis, an aeroelastic optimization method to minimize the vibration level is developed with due consideration to material uncertainty. Second-order polynomial response surfaces are used to approximate the objective function which smooths out the local minima or numerical noise in the design space. The aeroelastic optimization is carried out with the nominal values of composite material properties and the performance of final design is found to be optimum even for the perturbed values of material properties.