Thermosets show excellent mechanical properties and chemical resistance (for most automotive fluids) even at high temperatures up to 300 °C. Furthermore they can be highly efficient processed by injection molding. So they should be particularly suited for e.g. under the bonnet applications. However, the reality shows that thermosets are, except fiber reinforced composites, heavily underrepresented in technical applications. E.g. thermosetting components only account 0,2 % to a vehicle’s weight. Therefore reasons can be found in limited knowledge, e.g. relating mold filling behavior. The objective of the study is to analyze the influence of the mold filling behavior during injection molding of highly filled phenolic compounds on mechanical properties. Injection molding filling studies, mechanical testing and optical microscopy were done while varying mold geometry (injection gate and cavity height), mold temperature and injection rate during injection molding a highly filled phenolic compound. It was found that the mold filling behavior varies with altered injection molding parameters as well as the mold geometry. In consequence of this the mechanical properties change according to the resulting reinforcement orientation. The results can help to improve part and mold design for optimal load transmission.

Tesis para optar al grado de Magíster en Ciencias de la Ingeniería, Mención Ingeniería Estructural, Sísmica y Geotécnica / En el presente trabajo de investigación se evalúa el desempeño sísmico y el riesgo de colapso de marcos especiales a momento compuestos (C-SMF), utilizando la metodología de FEMA P695 [24]. Para llevar a cabo este planteamiento como primer punto se realizó el diseño de varias configuraciones de edificios prototipo en 2D de 3, 6, 8, 12 y 16 pisos de altura tomados de una planta típica, ubicados en diferente zonificación sísmica y tipo de suelo, aplicando la norma chilena NCh 433 [25]. Se incluye la no linealidad geométrica (efecto P-Delta) y la no linealidad del material al implementar modelos de plasticidad concentrada basados en fibras utilizando las curvas efectivas de esfuerzo-deformación para dicho fin. Se utilizó el software SAP2000 versión 19.1.1 para llevar a cabo todo el trabajo de investigación. Como segundo punto se realizaron análisis no lineales estáticos (Pushover) y no lineales dinámicos incrementales (Time History) para obtener el factor de sobreresistencia Ω, la ductilidad 𝜇���𝑇���, la intensidad media de colapso 𝑆���̂𝐶���𝑇���, la razón del margen de colapso CMR y así poder evaluar el desempeño sísmico comparando la razón del margen de colapso ajustado calculada ACMR con los valores admisibles propuestos por FEMA P695 [24]. El propósito de esta metodología es determinar los parámetros de respuesta (𝑅���,𝐶���𝑑���,𝛺���𝑜���) para que cuando sean propiamente implementados en los procesos de diseño, las edificaciones resulten con una seguridad equivalente contra el colapso durante un terremoto de manera similar a la seguridad que brindan los actuales códigos de diseño sísmico. Además, busca afirmar que el sistema estructural analizado asegure la protección de vida cuando posea una baja probabilidad de colapso (<10%) al ser sometida al sismo máximo considerado (MCE) con la finalidad de incluir el sistema C-SMF en normativa nacional para resistir fuerzas laterales inducidas por sismos. Un total de 30 diseños y 1373 análisis no lineales efectivos repartidos en 18 modelos seleccionados fueron los que se llevaron a cabo. Acorde a los resultados obtenidos, los factores de desempeño sísmico para uso normativo en C-SMF que se recomiendan son: Ωo=3.0, R*=6.0 y Cd=5.5; esto aplicando las limitaciones impuestas por FEMA P695 [24] y ASCE/SEI 7-16 [20]. La evaluación del desempeño fue satisfactoria para todos los casos individuales y grupales; sin embargo, se debe remarcar que los valores de CMR obtenidos disminuirán (aproximadamente en un 50%) si se realiza un Full IDA, lo que provocaría que el valor de CMR para las edificaciones de 16 pisos no cumpla con el criterio de aceptación. Con este antecedente, a criterio del autor, el sistema estructural C-SMF asegura la protección de vida y puede ser incluido en normativa nacional colocando una limitación en altura de 12 pisos.

O presente trabalho de Mestrado teve como objetivo produzir géis carregados de emulsão contendo nutrientes incorporados, visando a complementação da alimentação de leitões neonatos. Para alcançar tal objetivo, foram produzidas emulsões utilizando-se diferentes lipídios e tensoativos para definição preliminar sobre quais destes ingredientes seriam mais eficientes na formação de emulsões estáveis. As emulsões produzidas foram avaliadas em relação à distribuição de tamanho de gota e aspecto visual dentro de 24 h após a produção. A partir de tais resultados, algumas amostras foram escolhidas e foi estudado o aumento da concentração de lipídios, bem como a razão óleo:tensoativo e intensidade de agitação. Para cada emulsão estudada, esta era incorporada ao gel polissacarídico, e então realizava-se um estudo da estabilidade térmica a 40 e 50 °C. Após a definição da melhor concentração de lipídios, ocorreu o estudo da incorporação de nutrientes em diversas concentrações na emulsão. Novamente, as emulsões foram avaliadas por meio da distribuição de tamanho de gota, bem como pelo aspecto visual. Foi avaliada a estabilidade da emulsão ao longo de 28 dias, que indicou um sistema estável para o período indicado. Os géis carregados foram analisados quanto à quantidade de energia e à atividade de água, apresentando um baixo valor energético e atividade de água alta. Foram também caracterizados por análises reológicas, que indicaram que a presença da emulsão fortaleceu a estrutura do gel, indicando adesão das gotas à matriz biopolimérica. O gel carregado de emulsão apresentou estabilidade microbiológica, não tendo havido crescimento de fungos filamentosos e não-filamentosos, bem como a manutenção do pH. No entanto, houve alteração da cor ao longo da estocagem. Assim, foi possível produzir um gel carregado de emulsão contendo nutrientes, possibilitando a formação de um sistema estável. / The aim this work was to produce emulsion filled gels with the incorporation of nutrients for the complementation of nutrition of neonates piglets. For this, the emulsions were produced from a variety of lipids and surfactants to define, preliminarily, which of these ingredients would be efficient to form stable emulsions. The emulsions produced were evaluated by droplet size distribution and visual appearance within 24 hours after production. From these results, some samples were selected and the increase of lipid concentration was studied as well as the ratio oil:surfactant and the stirring intensity. For each emulsion studied, this was incorporated into the polysaccharide gel and then the thermal stability study at 40 and 50 °C was made. After setting the optimal concentration of lipids and a stirring intensity, there was the study of nutrientse incorporation at different concentrations in the emulsion. Again, the emulsions were evaluated by droplet size distribution, as well as by visual appearance. The emulsion stability was evaluated over 28 days, which indicated a stable system for this time. The emulsion filled gels were characterized for the amount of energy and water activity and presented as results low amount of energy and high water activity. In the rheological characterization, the results showed that the presence of emulsion strengthened the gel structure, indicating adhesion of the droplets to the biopolymer matrix. The emulsion filled gel showed microbiological stability has not been growing of filamentous and non-filamentous fungi, as well as pH stability. However, there was a change in color over the storage. Thus, it was possible to produce an emulsion-filled gel with nutrients, on which occurred the formation of a stable system.

O chocolate é um dos principais produtos oriundos do cacau, sendo comercializado em sua maior parte na forma de bombons maciços ou recheados. Bombons com recheio de fruta podem conter a fruta ou pedaços da fruta distribuídos no recheio. Eles podem ser produzidos em base fondant, gordura, geléia ou com o próprio chocolate (trufas), entre outros, adicionando-se aromas e corantes ou não. O objetivo deste trabalho foi produzir preparados de frutas e recheios para bombons em base fondant, gordura hidrogenada e chocolate branco (trufa), utilizando estes preparados como substituto parcial ou total de aromas e corantes na formulação final dos recheios. Os preparados foram elaborados utilizando-se açúcar invertido, xarope de glicose e água como matriz, adicionados de morango e maracujá liofilizados e casca de laranja, para conferir o aroma da fruta in natura, reduzindo de maneira significativa o uso de aromas e corantes artificiais. Avaliou-se pH nos preparados de frutas e nos recheios; teor de sólidos solúveis nos preparados de fruta; atividade de água nos recheios base fondant, gordura hidrogenada e \"trufa\". Os valores de pH apresentaram-se menores que 4,0 para os preparados e menores que 6,0 para os recheios. A atividade de água não apresentou variação durante o período estudado. O teor de sólidos solúveis encontrado foi de 68 ºBrix, 69 ºBrix e 73 ºBrix, respectivamente para os preparados de morango, maracujá e laranja. A composição centesimal foi feita para caracterizar os bombons quanto ao teor de gordura, proteínas, umidade, cinzas e valor energético. Os bombons recheados com açúcar fondant apresentam os menores teores de lipídeos, foram encontrados valores de proteínas maiores para as trufas. O valor energético destes produtos variou de 500 a 600 kcal por 100 g de produto. O estudo da textura dos bombons recheados foi feito a 25 ºC e caracterizou os bombons quanto a sua dureza, sendo que as trufas se mostraram os bombons de menor dureza. Os dados de atividade de água e dureza foram analisados através da ANOVA e Teste de Tukey. Na análise sensorial dos bombons recheados foi aplicado teste de aceitação global aos consumidores. A análise dos dados foi feita através da ANOVA, Teste de Tukey, Mapa de Preferência e Análise de Cluster. O estudo da reologia foi feito para os preparados de fruta, para os recheios base fondant e gordura hidrogenada a 25 ºC. Para as trufas foi feito o estudo reológico através do teste rotacional à 0 ºC e 70 ºC. Os ensaios oscilatórios utilizaram varredura de freqüência. A análise sensorial apresentou resultados significativos quanto à aceitação dos produtos, sendo que as trufas foram as que obtiveram as maiores notas, seguidas dos bombons com recheio base gordura hidrogenada. Os ensaios oscilatórios demonstraram que os preparados de fruta e os recheios nos sabores morango, maracujá e laranja são estáveis quando sujeitos a uma baixa freqüência. No teste rotacional, a curva de fluxo determinou o comportamento dos preparados. As curvas de fluxo obtidas através do teste rotacional, foram avaliadas quanto ao melhor modelo reológico aplicado. A utilização de um preparado de fruta, dando aos recheios características da fruta in natura, conferindo sabor e aroma sem a necessidade de nova adição de aroma e corante, em combinação com açúcar fondant, com gordura hidrogenada e nas trufas, mostrou-se uma maneira interessante de produzir um recheio de baixo custo, com longa vida de prateleira se comparado aos produtos artesanais presentes no mercado, conferindo aos produtos atributos bem aceitos pelo consumidor. / Chocolate is one of the most important products made from cacao, being major commercialized as chocolate filled or plain. Chocolate filled with fruit can contain the fruit or parts of it mixed in the filling. The fillings could be produced using fondant, fat, jelly or the white chocolate, as the truffles, with the addition of flavor and colorants or not. The objective of this work was to produce fruit mixes and filling for chocolate, using fondant, hydrogenated fat and White chocolate (truffles), using those mixes as replacers of flavor and colorants in the final formulations. The mixes were elaborated using inverted sugar, glucose syrup and water, mainly, freeze dried strawberry and passion fruit, and orange, was added to gave flavor of in nature fruit, reducing the use of artificial flavor and colorants. The pH was evaluated for the mixes and fillings; soluble solids content in the mixes; water activity in the fillings. The pH values showed to be lower than 4,0 to the mixes , and lower than 6,0 for the fillings. Water activity didn\' t show variability during the evaluated period. The soluble solids content was 68 ºBrix, 69 ºBrix and 73 ºBrix, respectively for strawberry, passion fruit and orange mix. The centesimal composition was done to characterize the chocolates filled showing the content of fat, protein, humidity, ashes and energetic value. The chocolates filled with fondant sugar presented the lower values of fat, protein was greater for the truffles. The energetic value varied between 500 to 600 kcal per 100 g of product. The texture study of chocolates filled was done at 25 ºC and characterized the hardness of them. The truffles presented the lower values for hardness. The data of water activity and hardness were analyzed trough ANOVA and Tukey test. Sensory evaluation of chocolates filled was done applying global evaluation test to consumers. The data analysis was done trough ANOVA, Tukey test, Internal Preference Mapping and Cluster Analysis. The rheological study was done at 25 ºC for the mixes, fondant and hydrogenated fat fillings, for the truffles the rotational test was done at 0 ºC and 70 ºC. The oscillatory test was done using a frequency sweep. The sensory evaluation presented significant results, regarding product acceptance, the truffles gotten the greater grades, followed by the hydrogenated fat chocolate filled. The oscillatory study showed stability for all the mixes and fillings, when those are subjected to lower frequencies. In the rotational study, the flow curve determined the mixes behavior. The flow curves obtained trough rotational test, were evaluated for the best rheological model which fitted them. The use of a fruit mix, giving characteristics of in nature fruit, with flavor and color without the need of adding artificial ones, combined with fondant, hydrogenated fat and for the truffles, showed to be an efficient way to produce fillings with low cost, and a greater shelf life, if compared with artisanal products of the market, being well accepted by consumers.

Ce travail porte sur la modélisation micromécanique des élastomères chargés. On cherche principalement à d'une part identifier l'influence des propriétés des différentes phases (morphologie et comportement) sur la réponse macroscopique, et d'autre part explorer les mécanismes d'interactions qui peuvent avoir lieu au sein de la micro-structure. Pour ce faire, on a mené une étude à deux échelles d'observations et ce à l'aide de simulations numériques basées sur l'homogénéisation. Le premier niveau correspond à une échelle mésoscopique pour laquelle on considère un Volume Élémentaire Représentatif (VER) bi-phasique, constitué d'un agglomérat de charge dissipatif, noyé dans une matrice hyperélastique. Le second niveau consiste, à une plus petite échelle, à explorer le comportement d'un agglomérat idéalisé, constitué de particules de charges infiniment rigides liées entre elles par une mince couche de gomme. Cette micro-structure est générée de manière aléatoire par un tirage de polygones de Voronoï. Des calculs éléments finis sont réalisés en élasticité linéaire et non-linéaire dans un contexte d'homogénéisation numérique en utilisant diverses techniques de localisation. Les différentes analyses menées montrent notamment que l'hypothèse d'affinité n'est pas adaptée à ce type de micro-structures et que le caractère incompressible de la gomme ainsi que son confinement jouent un rôle prépondérant sur le comportement mécanique de l'agglomérat. / This work focuses on the micro mechanical modeling of filled elastomers. The major question to be identified: firstly the influence of the properties of different phases (morphology and behavior) on the macroscopic response, and also to explore the mechanisms of interactions that take place within the micro-structure. To do this, we conducted a study at two scales of observations and using the numerical simulations based on homogenization. The first level corresponds to a mesoscopic scale for which we consider a representative elementary volume (REV), biphasic, consisting of a homogeneous dissipative inclusion (agglomerate) embedded in a hyperelastic matrix. The second level is at a smaller scale, to explore the behavior of an idealized agglomerate, consisting of infinitely rigid filler particles bounded together by a thin layer of rubber. This micro-structure is randomly generated by a random Voronoï polygons. Finite element calculations are performed in linear elasticity and nonlinear in the context of numerical homogenization using various localization techniques. The results show in particular that the assumption of affinity is not suitable for this type of micro-structures and the incompressibility of the rubber and its containment play an important role on the mechanical behavior of the agglomerate.

Windows reduce heat loss and heat gain by resisting conduction, convection, and radiation using thermal breaks, low-emissivity films, and window gaps. Contrary to advancing these resistive qualities, this research introduced a highly conductive gap medium using Al2O3 nanoparticles dispersed in deionized water to enhance thermal conductivity. The solution harnessed the photothermal properties of Al2O3 nanofluids to trap, store, and transport thermally charged fluids to heat exchangers to preheat air and water, and to generate electricity forming a transparent generator—the Nanowindow. Seven Nanowindow prototypes with varying orders of air and fluid columns were fabricated and tested using distilled water (H2Owindows) to establish a baseline of performance. A solar simulator was built to avoid environmental radiant flux irregularities providing a uniform test condition averaging 750–850 W/m2, and resulted in an undefined spectral match, Class B spatial uniformity, and Class B temporal stability. All Nanowindows were tested in a calibrated hot box determined to have a ±4% degree of accuracy based on four laboratory samples establishing a framework to conduct U-factor and solar heat gain coefficient (SHGC) measurements. Four heat exchange experiments and standardized window performance metrics (U-factor, SHGC, and visible transmission) where conducted on seven H2Owindows. The top two H2Owindows were then tested using Al2O3 nanofluids. The highest performing Nanowindow improved total convective heat transfer rates using Al2O3 by 90% over water baseline, and 61% improvement in preheat water experiments. Nanowindows coupled with thermoelectric generators generated a rated voltage of 0.31VDC/0.075ADC per 12in2 Nanowindow, an improvement of 38% over baseline. Standardized window performance metrics confirmed Nanowindow U-factors ranging from 0.23 to 0.54, SHGC from 0.43 to 0.67, and visible transmittance coefficient (VT) ranging from 0.27 to 0.38. The concept of nature as model system thinking provided a theoretical framework for the research and proof of concept experiment. Ultimately, the experiment shifted window gaps from resisting energy to harnessing solar energy. The Nanowindow thus presents a unique opportunity to turn vast glass facades into transparent generators to offset energy demand, and reduce greenhouse gases.

O chocolate é um dos principais produtos oriundos do cacau, sendo comercializado em sua maior parte na forma de bombons maciços ou recheados. Bombons com recheio de fruta podem conter a fruta ou pedaços da fruta distribuídos no recheio. Eles podem ser produzidos em base fondant, gordura, geléia ou com o próprio chocolate (trufas), entre outros, adicionando-se aromas e corantes ou não. O objetivo deste trabalho foi produzir preparados de frutas e recheios para bombons em base fondant, gordura hidrogenada e chocolate branco (trufa), utilizando estes preparados como substituto parcial ou total de aromas e corantes na formulação final dos recheios. Os preparados foram elaborados utilizando-se açúcar invertido, xarope de glicose e água como matriz, adicionados de morango e maracujá liofilizados e casca de laranja, para conferir o aroma da fruta in natura, reduzindo de maneira significativa o uso de aromas e corantes artificiais. Avaliou-se pH nos preparados de frutas e nos recheios; teor de sólidos solúveis nos preparados de fruta; atividade de água nos recheios base fondant, gordura hidrogenada e \"trufa\". Os valores de pH apresentaram-se menores que 4,0 para os preparados e menores que 6,0 para os recheios. A atividade de água não apresentou variação durante o período estudado. O teor de sólidos solúveis encontrado foi de 68 ºBrix, 69 ºBrix e 73 ºBrix, respectivamente para os preparados de morango, maracujá e laranja. A composição centesimal foi feita para caracterizar os bombons quanto ao teor de gordura, proteínas, umidade, cinzas e valor energético. Os bombons recheados com açúcar fondant apresentam os menores teores de lipídeos, foram encontrados valores de proteínas maiores para as trufas. O valor energético destes produtos variou de 500 a 600 kcal por 100 g de produto. O estudo da textura dos bombons recheados foi feito a 25 ºC e caracterizou os bombons quanto a sua dureza, sendo que as trufas se mostraram os bombons de menor dureza. Os dados de atividade de água e dureza foram analisados através da ANOVA e Teste de Tukey. Na análise sensorial dos bombons recheados foi aplicado teste de aceitação global aos consumidores. A análise dos dados foi feita através da ANOVA, Teste de Tukey, Mapa de Preferência e Análise de Cluster. O estudo da reologia foi feito para os preparados de fruta, para os recheios base fondant e gordura hidrogenada a 25 ºC. Para as trufas foi feito o estudo reológico através do teste rotacional à 0 ºC e 70 ºC. Os ensaios oscilatórios utilizaram varredura de freqüência. A análise sensorial apresentou resultados significativos quanto à aceitação dos produtos, sendo que as trufas foram as que obtiveram as maiores notas, seguidas dos bombons com recheio base gordura hidrogenada. Os ensaios oscilatórios demonstraram que os preparados de fruta e os recheios nos sabores morango, maracujá e laranja são estáveis quando sujeitos a uma baixa freqüência. No teste rotacional, a curva de fluxo determinou o comportamento dos preparados. As curvas de fluxo obtidas através do teste rotacional, foram avaliadas quanto ao melhor modelo reológico aplicado. A utilização de um preparado de fruta, dando aos recheios características da fruta in natura, conferindo sabor e aroma sem a necessidade de nova adição de aroma e corante, em combinação com açúcar fondant, com gordura hidrogenada e nas trufas, mostrou-se uma maneira interessante de produzir um recheio de baixo custo, com longa vida de prateleira se comparado aos produtos artesanais presentes no mercado, conferindo aos produtos atributos bem aceitos pelo consumidor. / Chocolate is one of the most important products made from cacao, being major commercialized as chocolate filled or plain. Chocolate filled with fruit can contain the fruit or parts of it mixed in the filling. The fillings could be produced using fondant, fat, jelly or the white chocolate, as the truffles, with the addition of flavor and colorants or not. The objective of this work was to produce fruit mixes and filling for chocolate, using fondant, hydrogenated fat and White chocolate (truffles), using those mixes as replacers of flavor and colorants in the final formulations. The mixes were elaborated using inverted sugar, glucose syrup and water, mainly, freeze dried strawberry and passion fruit, and orange, was added to gave flavor of in nature fruit, reducing the use of artificial flavor and colorants. The pH was evaluated for the mixes and fillings; soluble solids content in the mixes; water activity in the fillings. The pH values showed to be lower than 4,0 to the mixes , and lower than 6,0 for the fillings. Water activity didn\' t show variability during the evaluated period. The soluble solids content was 68 ºBrix, 69 ºBrix and 73 ºBrix, respectively for strawberry, passion fruit and orange mix. The centesimal composition was done to characterize the chocolates filled showing the content of fat, protein, humidity, ashes and energetic value. The chocolates filled with fondant sugar presented the lower values of fat, protein was greater for the truffles. The energetic value varied between 500 to 600 kcal per 100 g of product. The texture study of chocolates filled was done at 25 ºC and characterized the hardness of them. The truffles presented the lower values for hardness. The data of water activity and hardness were analyzed trough ANOVA and Tukey test. Sensory evaluation of chocolates filled was done applying global evaluation test to consumers. The data analysis was done trough ANOVA, Tukey test, Internal Preference Mapping and Cluster Analysis. The rheological study was done at 25 ºC for the mixes, fondant and hydrogenated fat fillings, for the truffles the rotational test was done at 0 ºC and 70 ºC. The oscillatory test was done using a frequency sweep. The sensory evaluation presented significant results, regarding product acceptance, the truffles gotten the greater grades, followed by the hydrogenated fat chocolate filled. The oscillatory study showed stability for all the mixes and fillings, when those are subjected to lower frequencies. In the rotational study, the flow curve determined the mixes behavior. The flow curves obtained trough rotational test, were evaluated for the best rheological model which fitted them. The use of a fruit mix, giving characteristics of in nature fruit, with flavor and color without the need of adding artificial ones, combined with fondant, hydrogenated fat and for the truffles, showed to be an efficient way to produce fillings with low cost, and a greater shelf life, if compared with artisanal products of the market, being well accepted by consumers.

The subject of this thesis is the development of new ultrasound inspection techniques for detection of cracks that are smaller than the wavelength of the inspecting wave and the characterization of cracks in fluid-filled pipes as either surface-breaking or subsurface. The spectrum of the scattered field of a partially closed crack comprises harmonic components not expected to be found in the case of linear scatterers such as pores or inclusions. Paper A presents an experimental investigation into the linear reflection and generation of the 2nd harmonic component following the incidence of an ultrasonic wave onto a dry or water-confining interface formed by elasto-plastic steel-steel surfaces in contact. The results indicate that water has an unexpected effect on the reflection, at low interfacial pressures, suggesting that fluid mediated forces play a role not accounted for in current models. The level of the generation of the 2nd harmonic measured provides support for further development of the technique for detection of dry, partially closed cracks or fluid-filled, nearly open cracks. A theoretical model describing the nonlinear scattering of acoustic waves by surface-breaking cracks with faces in partial contact is presented in Paper B. Both linear and nonlinear response of the crack are shown to be the largest for a SV wave incident on the surface containing the crack at an angle just above the critical angle for longitudinal waves. A method which provides information on whether a fracture is surface-breaking or subsurface has been modelled and its optimal experimental set-up examined in Paper C. The main assumption of the model is that water carried by pressurized pipes infiltrates and fills a surface-breaking crack, while a subsurface crack is dry. The model simulates an inspection in which the modulation technique is employed and the surface hosting the crack is not accessible. A parameter, constructed with signals recorded in backscattering configuration during a modulation cycle, is examined and shown to provide a clear criterion to distinguish subsurface from surface-breaking cracks when a SV wave at 45 degree incidence is employed as a probe. Finally, in Paper D the modulation technique is experimentally tested on steel beams that host surface-breaking fatigue cracks. The method is shown to be a successful tool to distinguish a dry from a fluid-filled crack. Furthermore, it is revealed that the dynamics of the fluid needs to be accounted for in a more accurate simulation tool. / QC 20100906

The guided wave technique is commonly used for rapidly long-range pipeline inspection without removing the insulation of pipes. The torsional mode T(0,1) of the guided waves is usually generated to detect the defects in pipelines, since it has the advantage of being non-dispersive across the whole frequency range. However, a large number of pipelines are carrying fluid, wrapped with the coating material, and supported with clamp for the necessary manufacturing process in refinery and petro-chemical industrials. When these works are employed on the pipeline, the propagating guided waves may vary with the contents of material and how well the material compact on the pipe. Some energy of the incident guided wave in the pipe wall may leak into inside of contents or outside of wrapped materials and reduce the wave propagation distance. The effect of the fluid-filled pipe, the wrapped pipe, and the clamp support mounted on the pipe for guided wave propagation is investigated by both simulative and experimental methods. The wave structure of the T(0,1) mode in the pipes is analyzed by using the DISPERSE software for various cases to evaluate its influence to the guided wave propagation on the pipe. The amplitudes of the reflected signals from various features on the pipe are also measured using pipe screening system for calculating the attenuation of guided waves due to the features. The trend for the results is in good agreement between the experiments andpredictions for all cases of researches in this dissertation. It is found that the low viscosity liquid deposited in the pipe, such as water, diesel oil, and lubricant, has no effect on the torsional mode; while the high viscous of the fuel oil deposited in the pipe attenuates the reflection signal heavily for the pipe carrying fluid. In addition, both the full-filled and half-filled contents in the pipe are also studied in this case. The effects of the half-filled are the same as the full-filled results obtained. For the pipe wrapped with the coated material, the adhesive strength of the coated material is strong, such as bitumen and polyethylene; the attenuation of the guided waves is high; and there is almost no effect for mineral wool coating. Furthermore, the traveling distance of the guided waves in the pipe is also evaluated for various cases of the coated materials. The results indicate that the higher attenuation of the guided waves for the coated material, the shorter of the traveling distance in the pipe. For the clamp support mounted on pipe, the attenuation of the guided waves for the clamp support with a rubber gasket in between the pipe and the clamp is heavier than the case of clamp support without the rubber gasket is. Furthermore, the higher torque setting on the clamp (with or without the rubber gasket), the higher amplitude of the reflected signal is measured for the guided wave propagation. The effect of the frequency excitation is additionally demonstrated in this dissertation. It is noted that the higher amplitude of the reflected signal, the lower frequency excitation; moreover, theresonant effect is observed in the case of the clamp support with rubber gasket during the torque setting in the experiments. Good agreement has been obtained between the experiments and theoretical calculations of this effect.

The use of composite steel-concrete columns and beam-columns in many structural systems is increasing globally due to the intrinsic synergy when these materials are designed and detailed together properly. However, limited test data are available to justify the structural system response factors and comprehensive design equations in current design specifications. This research, through the testing of 18 full-scale, slender concrete-filled steel tube (CFT) beam-columns, attempts to address the latter need. The circular and rectangular CFT specimens tested for this research are by far the longest and the most slender full-scale CFT members tested worldwide. These CFT specimens were subjected to a complex load protocol that includes pure compression, uniaxial and biaxial bending combined with compression, pure torsion, and torsion combined with compression. In addition, data from the hydrostatic pressure on the steel tubes due to the fresh concrete at casting was evaluated. The single most important contribution of this research is the clarification of the interaction between strength and stability in slender composite concrete-filled columns and beam-columns. Parallel to the experimental study, advanced computational analyses were carried out to calibrate material and element models that characterize the salient features of the observed CFT response, such as steel local buckling and residual stresses, concrete confinement, stability effects, strength, and stiffness degradation, among others. Based on the observed behavior, simplified guidelines for the computation of the strength and stiffness parameters for CFT columns and beam-columns are proposed for design purposes.