Hat sections, single and double, made of steel are frequently encountered in automotive body structural components such as front rails, B-Pillar, and rockers of unitized-body cars. These thin-walled components can play a significant role in terms of crashworthiness and impact energy absorption, through a nonlinear phenomenon called as progressive dynamic buckling. As modern vehicle safety design relies heavily on computer-aided engineering, there is a great need for analysis-based predictions to yield close correlation with test results. Although hat sections subjected to axial loading have been studied widely in the past, there is scanty information in published literature on modeling procedures that can lead to robust prediction of test responses. In the current study, both single-hat and double-hat components made of mild steel are studied extensively experimentally and numerically to quantify statistical variations in test responses such as peak load, mean load and energy absorption, and formulate modeling conditions for capturing elasto-plastic material behavior, strain rate sensitivity, spot-welds, etc. that can lead to robust predictions of force-time and force-displacement histories as well as failure modes. In addition, keeping initial stages of vehicle design in mind, the effectiveness of soft computing techniques based on polynomial regression analysis, radial basis functions and artificial neural networks for quick assessment of the behaviors of steel hat sections has been demonstrated. The study is extended to double-hat sections subjected to eccentric impact loading which has not been previously reported. A lightweight enhancement of load carrying capacity of steel hat section components has been investigated with PU (polyurethane) foam-filled single and double hat sections, and subjecting the same to quasi-static and axial impact loading. Good predictions of load-displacement responses are again obtained and shortening of fold lengths vis-à-vis hollow sections is observed. Finally, the performance of hat sections made of glass fiber-reinforced composites is studied as a potential lightweight substitute to steel hat section components. The challenging task of numerical prediction of the behaviors of the composite hat sections has been undertaken using a consistent modeling and analysis procedure described earlier and by choosing an appropriate constitutive behavior available in the popular explicit contact-impact analysis solver, LS-DYNA.

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Denna rapport behandlar genomförandet av ett examensarbete på högskolenivå inom maskinteknik vid Högskolan i Borås. Examensarbetet har utförts hos SP Sveriges Tekniska Forskningsinstitut AB, enheterna SP Safety – Mechanical Research i Borås och Göteborg samt Food and Bioscience i Göteborg. Den största delen av arbetet har utförts vid sektionen Mechanical Research Göteborg. Målet med examensarbetet var att kombinera analys av experimentell bilddata från konfokalmikroskopi och mekanisk lastdata från en dragcell som gradvis deformerar ett polyuretanskum med modellering av skummets mekaniska egenskaper med hjälp av finita elementmetoder (FEM). Syftet var att bestämma elasticitetsmodul och Poissons tal. En viktig del av projektet var också att säkerställa hög repeterbarhet och möjliggöra vidareutveckling av metodiken genom att skapa rutiner för hur de olika delmomenten i arbetscykeln bäst utförs. Polyuretanskum, liksom många andra mjuka heterogena biomaterial saknar i dagsläget uppmätta eller beräknade mekaniska egenskaper. Därför finns potential för att den framtagna metodiken kommer till användning för att bestämma materialparametrar och analysera beteenden för fler av dessa material. Genom att bestämma materialparametrarna är det sedan möjligt att¬ utföra hållfasthetsberäkningar på sådana material, och korrelera materialparametrarna till processparametrarna vid tillverkningen för att optimera materialets egenskaper. Studien började med att ett prov av polyuretanskum placerades i en dragcell där det utsattes för en kraft så att det gradvis deformerades. Med hjälp av ett konfokalmikroskop kan hela deformationsprocessen följas i hög upplösning. De framtagna bildserierna analyserades sedan med hjälp av DaVis, en mjukvara som genomför så kallad digital image correlation-analys, med vars hjälp lokala förskjutningar kunde bestämmas. För att kunna utföra FEM-beräkningar delades materialstrukturen in i elementnät med hjälp av den fritt tillgängliga programvaran OOF2. Elementnät och förskjutningsdata importerades sedan till Matlab och insticksmodulen CalFEM. Med hjälp av CalFEM konstruerades en materialmodell med elasticitetsmodul och Poissons tal som inparametrar. Valideringskriterium användes för att säkerställa korrektheten i finita elementanalyserna. Elasticitetsmodulen bestämdes till 4.6 MPa och Poissons tal till 0.33 ± 0.06. Med tillgängliga data kunde inte modellen användas för att uppskatta båda parametrarna samtidigt. Poissons tal bestämdes genom manuell analys av bildserierna. Metodiken kan förbättras och vidareutvecklas genom att analysera fler provbitar för att ta hänsyn till lokala fluktuationer i materialstrukturen, samt avbilda provet i tredimensioner. Tredimensionell avbildning skulle också möjliggöra konstruktion av en tredimensionell beräkningsmodell av materialet. / This bachelor thesis deals with the implementation of a degree in mechanical engineering at the University of Borås. The thesis work has been conducted at SP Technical Research Institute of Sweden AB at the departments SP Safety – Mechanical Research in Borås and Gothenburg and Food and Bioscience in Gothenburg. The major part of the work has been done at the Mechanical Research department in Gothenburg. The aim of the thesis work was to combine analysis of experimental image data from confocal laser scanning microscopy and mechanical load data from a tensile cell that gradually deforms a polyurethane foam with modelling of the mechanical properties of the foam using finite element methods (FEM). The purpose was to determine Young’s modulus and Poisson's ratio. A crucial part of the project was also to facilitate a high degree of repeatability and further development of the method through establishing routines and best practices for how to implement different parts of the method. There is currently a lack of measured or calculated properties for polyurethane foams, as is the case also for many other soft heterogeneous biomaterials. This implies that the developed method has potential use for determining material parameters and analyzing behavior also for other materials of this type. Determining the material parameters facilitates strength calculations on these materials and makes it possible to correlate material parameters to process parameters during manufacturing to optimize material performance. The polyurethane foam was placed in a tensile cell, exposed to a force and slowly, gradually deformed. Using a confocal microscope, the entire deformation process can be observed at high resolution. The obtained image series were then analyzed using DaVis, a software that can perform so called digital image correlation analysis where local displacements could be determined. In order to perform the finite element calculations, the material structure was divided into an element mesh using the software OOF2. The element mesh and displacement data were then imported to Matlab and the plugin module CalFEM. Using CalFEM, a material model involving Young’s modulus and Poisson’s ratio was created. Young’s modulus was determined to be 4.6 MPa and Poisson’s ratio 0.33 ± 0.06. Using the available data, the model was insufficient to determine both parameters simultaneously. Therefore, Poisson’s ratio was determined through manual analysis of the image series. The method can be improved and further developed mainly by analyzing several samples to account for local fluctuations in the material structure and by using three-dimensional imaging methods. The latter would also open up for creating a three-dimensional model of the material.

Avaliou-se a influência da recirculação da fase líquida e do regime de alimentação em reator anaeróbio no tratamento de esgoto sanitário. Utilizou-se um reator anaeróbio operado em bateladas seqüenciais, contendo biomassa imobilizada (ASBBR), em escala piloto, com volume total de 1,2 \'M POT.3\' (\'fi\' 1,0 m e altura 1,53 m). O leito suporte para a imobilização da biomassa era constituído por matrizes cúbicas de espuma de poliuretano, com 5 cm de aresta, confinadas em cesto de aço inox 304, colocado no interior do reator. A influência da recirculação da fase líquida sobre o desempenho do ASBBR quanto à remoção de matéria orgânica e quanto ao arraste de sólidos foi avaliada submetendo-se o reator às velocidades ascensionais de 1,27; 3,82; 7,64 e 10,18 m/h resultantes das diferentes vazões de recirculação impostas. Contrariamente ao observado em pesquisas anteriores em reatores operados em escala de bancada e alimentados com água residuária sintética, não houve aumento significativo da eficiência do reator com o aumento da velocidade ascensional no tratamento de esgoto sanitário. A influência do regime de alimentação de esgoto sanitário no desempenho do ASBBR foi avaliada submetendo-se o reator a tempos de enchimento correspondentes a 0,25 e 0,5 do tempo total de ciclo, utilizando-se a vazão de recirculação de 6 \'M POT.3\'/h, que foi a que apresentou os melhores resultados nos ensaios anteriores. Concluiu-se que o reator pode ser operado sob batelada alimentada com duração de até 0,5 tempo de ciclo, sem que seu desempenho seja significativamente alterado. Esse resultado é importante, pois representa que o sistema de tratamento composto por reatores ASBBR pode ser projetado com número menor de reatores. A fim de esclarecer dúvidas sobre o desempenho do ASBBR observado no tratamento de água residuária de composição complexa (esgoto sanitário), o reator foi alimentado com água residuária facilmente degradável (etanol). O desempenho do reator foi aquém do esperado, mesmo quando alimentado com composto de fácil degradação. Os ensaios de atividade metanogênica específica (AME) demonstraram que houve decréscimo dos valores de AME com o aumento da velocidade ascensional. Os valores obtidos foram 0,0632; 0,0509; 0,0248 e 0,0299 g DQO-CH4/(g STV.d), respectivamente, para os valores de Va de 1,27; 3,82; 7,64 e 10,19 m/h. Concluiu-se que a baixa eficiência de remoção de matéria orgânica deveu-se ao abaixamento progressivo da atividade metanogênica do lodo, cujas causas não puderam ser completamente esclarecidas nesta pesquisa. / The influence of the liquid phase recirculation and the feeding regimen on the performance of an anaerobic sequencing batch reactor containing immobilized biomass (ASBBR) applied for the treatment of domestic sewage was evaluated. Biomass immobilization was provided by a basket containing cubic polyurethane foam matrices (5 cm side) inside the 1.2 \'M POT.3\' (1.0 m diameter and 1.53 m height) pilot-scale reactor. The influence of the liquid phase recirculation on the reactor performance in respect to organic matter and solids wash-out was verified by subjecting the reactor to a wide range of up flow velocities (1.27; 3.82; 7.64 and 10.18 m/h) resulting from different recirculation flow rates imposed. The increase of the up flow velocity did not increase the efficiency of the pilot reactor as expected. This result contradicts those obtained with bench-scale ASBBR experiments treating synthetic wastewaters. The influence of the feeding regimen was verified by subjecting the reactor to feeding times correspondent to 0.25 and 0.50 of the total cycle time, at the recirculation flow rate of 6 \'M POT.3\'/h. It could be concluded that the reactor can be operated at the feeding batch mode up to 0.5 of the cycle time. This result is important for full scale applications considering that a treatment system composed of ASBBR reactors can be designed using a lower number of units. In order to clear some aspects related to the limited performance of the ASBBR reactor treating a complex wastewater (sewage), the reactor was subjected to an easily degradable wastewater (ethanol). However, the performance was not improved even when the reactor was treating an easily degradable compound. The results from the specific methanogenic activity (SMA) demonstrated a decrease on the values of SMA with the increase of the up flow velocity. The values of SMA were 0.0632; 0.0509; 0.0248 and 0.0299 g DQO-CH4/(g STV.d) for the Va of 1.27; 3.82; 7.64 and 10.19 m/h respectively. It could be concluded that the low efficiency obtained for organic matter removal was due mainly to the progressive decrease of the sludge methanogenic activity. The causes for that behaviour could not be completely explained in this research. It could be concluded that the reactor performance was iv clearly limited by the low productivity of the methanogenic populations present in the biomass.

Métodos de Microbiologia de anaeróbios estritos e de Biologia Molecular foram empregados para se conhecer a diversidade de microrganismos relacionados à degradação de ascarel em reatores anaeróbios metanogênicos. A avaliação de potencial metanogênico foi realizada para a escolha da melhor condição nutricional, bem como, para a seleção de material suporte e solvente adequado a solubilização do ascarel. Nos ensaios em batelada, a produção de metano foi maior nos reatores contendo etanol (média de 0,22 - 0,46 molCH4/gSTV, 46h). Remoção de 85,6% (86,7 mg/L de PCB em Aroclor 1016 e 1260) foi obtida na condição com espuma de poliuretano, etanol (46g/L) e formiato (680 mg/L). Diferentes solventes e surfactantes, tais como, DMSO, dioxano, ácido acético, ácido fórmico, n-hexano, acetona, etano, metanol, Tween 80, SDS (10%) e Triton X-100 foram avaliados para a solubilização de ascarel. Dentre esses, metanol, Triton X-100 e ácido fórmico foram eleitos para a realização de ensaio em reatores em batelada contendo espuma de poliuretano, com o propósito de avaliar o potencial metanogênico na degradação de PCB. Os valores de produção de metano foram muito semelhantes (0,21 0,38 molCH4/mLgSTV, 45h) nas diferentes condições, no entanto, a remoção de PCB foi maior nos reatores com metanol 790 mg/L (86,6%), ácido Fórmico 600 mg/L (84,5%) e Triton X-100 1% (72,1%). Portanto, a melhor condição foi contemplada para a operação do reator anaeróbio horizontal de leito fixo (RAHLF) no tratamento do ascarel, ou seja, células imobilizadas em espuma de poliuretano, etanol e formiato (como fonte de carbono), Triton X-100 (0,1%) e metanol (como solvente). No RAHLF, a remoção média de matéria orgânica (DQO) foi de 91% para concentração afluente média de 1270 mg/L. A presença de morfologias semelhantes à Methanosarcina e bacilos fluorescentes foi confirmada em exames microscópicos. Na análise filogenética, por meio de PCR/DGGE e seqüenciamento das bandas recortadas, os grupos encontrados foram relacionados aos Filos Proteobacteria, Firmicutes, Spirochaetes, Chlorobi e Chloroflexi, sendo que neste último estão incluídos representantes relacionados a degradação de PCBs. Dentre as arquéias metanogênicas verificou-se similaridade de 99% e 97% com Methanosaeta sp. e Methanolinea sp., relacionadas com a metanogenese acetoclástica e hidrogenotrófica, respectivamente / Molecular biology and microbiology methods were used to study the microbial communities related to degradation of ascarel at methanogenic conditions in an anaerobic reactor. The methanogenic potential was evaluated to choose the better nutritional condition as well as to select the better support material and the most suitable solvent to favor the solubilization of ascarel. The methane production was higher (0.22 0.46 molCH4/mLgSTV, 46h) in batch reactors containing ethanol (46 g/L) and formate (680 mg/L), the PCB elimination attaining 85.6% (86.7 mg/L de PCB as Aroclor 1016 and 1260) when Polyuretane foam was used as support material. Different solvents, namely DMSO, dioxane, n-hexane, acetic acid, formic acid, acetone, ethane, methanol, and surfactants, such as 10% SDS,, Triton X-100, were evaluated aiming o determine the better condition to solubilize ascarel. According to the results of such experiments, methanol, formic acid and Triton X-100 were selected for carrying out the batch experiments in reactors containing polyurethane foam to evaluate the methane production during the PCBs degradation. Regardless of the operation conditions the methane production rates were similar (0.21 0.38 molCH4/gSTV, 45h), however the elimination of PCB was higher in the reactors containing methanol (790 mg/L), formic acid (600 mg/L) and Triton X-100 (1%). Therefore, the better condition for treating ascarel-containing residues in a bench-scale horizontal-flow immobilized biomass (HAIB) was attained with cells immobilized in polyurethane foam when ethanol and formate were used as carbon sources, and in presence of Triton X-100 and methanol, the average elimination of organic material attaining 91% for affluent concentration of 1270 mg/L. The presence of Methanosarcina and fluorescent rods was confirmed by microscopy analysis. According to the filogenetics analysis, which was carried out by PCR/DGGE and band-sequencing, the Bacteria domain are related to the Filos Proteobacteria, Firmicutes, Spirochaetes, Chlorobi and Chloroflexi, this latter being directly related to the degradation of PCB. Among the methanogenic Archea, a similiraty of 99% and 97% was observed to Methanosaeta sp. and Methanolinea sp. related to acetoclastic and hydrogenthrophic methanogenesis, respectively

Os objetivos deste trabalho foram avaliar o desempenho do reator anaeróbio operado em batelada seqüencial quando submetido ao aumento progressivo da concentração de glicose e estimar os parâmetros cinéticos da degradação da glicose. Inicialmente o reator foi operado com ciclos de 8 horas, tratando glicose nas concentrações, aproximadas, de 500, 1000 e 2000 mg/L. Não foi detectada glicose no efluente nas três condições. O reator operou de maneira estável, tratando aproximadamente 500 mg/L de glicose, com eficiência na remoção da DQO filtrada entre 93% e 97%. Na operação com concentrações de glicose no afluente próximas de 1000 mg/L e 2000 mg/L, observou-se instabilidade operacional, principalmente devido à produção de polímeros extracelulares (EPS) que comprometeram a hidrodinâmica e a transferência de massa no sistema. Os valores médios da concentrações de ácidos voláteis no efluente foram de 159 ± 72 mg/L e 374 ± 92 mg/L, respectivamente. Aos perfis de concentração de glicose foi ajustado modelo de primeira ordem, enquanto que um modelo modificado, contemplando concentração residual de matéria orgânica, foi ajustado aos perfis temporais de DQO. Para verificar a formação do EPS, operou-se o reator com 3 horas de ciclo nas concentrações, aproximadas, de 500 e 1000 mg/L. Esta fase teve como objetivo verificar a hipótese, segundo a qual, a produção de EPS seria resultado da exposição da biomassa a baixas concentrações de matéria orgânica por longo período. Dessa forma, reduzindo o tempo de ciclo, a exposição a baixas concentrações também seria reduzida. No entanto, embora o reator tenha operado com relativa estabilidade, verificou-se formação de grande quantidade de EPS logo na primeira condição operacional, com aproximadamente, 500 mg/L de glicose no afluente, indicando que a hipótese não estava correta. / The main objectives of this study were to evaluate the performance of the anaerobic sequencing batch reactor when subjected to a progressive increasing of the influent glucose concentration and estimate the kinetic parameters of glucoses degradation. Initially the reactor was operated with 8-hour cycles, treating glucose at concentrations of 500, 1000 and 2000 mg/L. Glucose was not detected in the effluent in all these three conditions. The reactor showed operating stability treating glucose concentration of approximately 500mg/L, with efficiencies between 93% to 97% in the filtrated COD removal. In the operation with glucose concentrations of 1000 mg/L and 2000 mg/L, approximately, it could be noticed an operational instability, caused mainly by a production of extracellular polymers (EPS) leading to hydrodynamic and mass transfer problems in the reactor. The mean values of volatile acids concentration in the effluent were about 159 ± 72mg/L and 374 ± 92mg/L, respectively. A first order model was adjusted to glucose concentration profiles, and a modified model, including a residual concentration of substrate, was adjusted to COD temporal profiles. To verify the EPS formation, the reactor was operated with 3-hour cycle in the concentrations of 500 and 1000 mg/L This stage had the objective of verifying if the EPS production would result from the exposure of the biomass to low concentration of substrate for a long period of time. Thus, reducing the time cycle, the exposure to low concentrations would also be reduced. Nevertheless, even with the reactor operating with relative stability, the hypotheses could not be verified due the formation of a large amounts of EPS right in the first operational condition with approximately to 500 mg/L of glucose in the influent, showing that the hypothesis was not right.

Métodos de Microbiologia de anaeróbios estritos e de Biologia Molecular foram empregados para se conhecer a diversidade de microrganismos relacionados à degradação de ascarel em reatores anaeróbios metanogênicos. A avaliação de potencial metanogênico foi realizada para a escolha da melhor condição nutricional, bem como, para a seleção de material suporte e solvente adequado a solubilização do ascarel. Nos ensaios em batelada, a produção de metano foi maior nos reatores contendo etanol (média de 0,22 - 0,46 molCH4/gSTV, 46h). Remoção de 85,6% (86,7 mg/L de PCB em Aroclor 1016 e 1260) foi obtida na condição com espuma de poliuretano, etanol (46g/L) e formiato (680 mg/L). Diferentes solventes e surfactantes, tais como, DMSO, dioxano, ácido acético, ácido fórmico, n-hexano, acetona, etano, metanol, Tween 80, SDS (10%) e Triton X-100 foram avaliados para a solubilização de ascarel. Dentre esses, metanol, Triton X-100 e ácido fórmico foram eleitos para a realização de ensaio em reatores em batelada contendo espuma de poliuretano, com o propósito de avaliar o potencial metanogênico na degradação de PCB. Os valores de produção de metano foram muito semelhantes (0,21 0,38 molCH4/mLgSTV, 45h) nas diferentes condições, no entanto, a remoção de PCB foi maior nos reatores com metanol 790 mg/L (86,6%), ácido Fórmico 600 mg/L (84,5%) e Triton X-100 1% (72,1%). Portanto, a melhor condição foi contemplada para a operação do reator anaeróbio horizontal de leito fixo (RAHLF) no tratamento do ascarel, ou seja, células imobilizadas em espuma de poliuretano, etanol e formiato (como fonte de carbono), Triton X-100 (0,1%) e metanol (como solvente). No RAHLF, a remoção média de matéria orgânica (DQO) foi de 91% para concentração afluente média de 1270 mg/L. A presença de morfologias semelhantes à Methanosarcina e bacilos fluorescentes foi confirmada em exames microscópicos. Na análise filogenética, por meio de PCR/DGGE e seqüenciamento das bandas recortadas, os grupos encontrados foram relacionados aos Filos Proteobacteria, Firmicutes, Spirochaetes, Chlorobi e Chloroflexi, sendo que neste último estão incluídos representantes relacionados a degradação de PCBs. Dentre as arquéias metanogênicas verificou-se similaridade de 99% e 97% com Methanosaeta sp. e Methanolinea sp., relacionadas com a metanogenese acetoclástica e hidrogenotrófica, respectivamente / Molecular biology and microbiology methods were used to study the microbial communities related to degradation of ascarel at methanogenic conditions in an anaerobic reactor. The methanogenic potential was evaluated to choose the better nutritional condition as well as to select the better support material and the most suitable solvent to favor the solubilization of ascarel. The methane production was higher (0.22 0.46 molCH4/mLgSTV, 46h) in batch reactors containing ethanol (46 g/L) and formate (680 mg/L), the PCB elimination attaining 85.6% (86.7 mg/L de PCB as Aroclor 1016 and 1260) when Polyuretane foam was used as support material. Different solvents, namely DMSO, dioxane, n-hexane, acetic acid, formic acid, acetone, ethane, methanol, and surfactants, such as 10% SDS,, Triton X-100, were evaluated aiming o determine the better condition to solubilize ascarel. According to the results of such experiments, methanol, formic acid and Triton X-100 were selected for carrying out the batch experiments in reactors containing polyurethane foam to evaluate the methane production during the PCBs degradation. Regardless of the operation conditions the methane production rates were similar (0.21 0.38 molCH4/gSTV, 45h), however the elimination of PCB was higher in the reactors containing methanol (790 mg/L), formic acid (600 mg/L) and Triton X-100 (1%). Therefore, the better condition for treating ascarel-containing residues in a bench-scale horizontal-flow immobilized biomass (HAIB) was attained with cells immobilized in polyurethane foam when ethanol and formate were used as carbon sources, and in presence of Triton X-100 and methanol, the average elimination of organic material attaining 91% for affluent concentration of 1270 mg/L. The presence of Methanosarcina and fluorescent rods was confirmed by microscopy analysis. According to the filogenetics analysis, which was carried out by PCR/DGGE and band-sequencing, the Bacteria domain are related to the Filos Proteobacteria, Firmicutes, Spirochaetes, Chlorobi and Chloroflexi, this latter being directly related to the degradation of PCB. Among the methanogenic Archea, a similiraty of 99% and 97% was observed to Methanosaeta sp. and Methanolinea sp. related to acetoclastic and hydrogenthrophic methanogenesis, respectively

La mousse de polyuréthane est un matériau cellulaire caractérisé par un spectre de propriétés mécaniques intéressant : une faible densité, une capacité à absorber l’énergie de déformation et une faible raideur.Elle présente également des propriétés telles qu’une excellente isolation thermique et acoustique, une forte absorption des liquides et une diffusion complexe de la lumière. Ce spectre de propriétés fait de la mousse de polyuréthane un des matériaux couramment utilisés dans de nombreuses applications phoniques, thermiques et de confort. Pour contrôler la vibration transmise aux occupants des sièges, plusieurs dispositifs automatiques de régulation et de contrôle sont actuellement en cours de développement tels que les amortisseurs actifs et semi-actifs. La performance de ces derniers dépend bien évidemment de la prédiction des comportements de tous les composants du siège et en particulier la mousse. D’une façon générale, il est indispensable de modéliser le comportement mécanique complexe de la mousse de polyuréthane et d’identifier ses propriétés quasi-statique et dynamiques afin d’optimiser la conception des systèmes incluant la mousse en particulier l’optimisation de l’aspect confort. Dans cette optique, l’objectif principal de cette thèse consiste à implémenter des modèles mécaniques de la mousse de polyuréthane fiables et capables de prévoir sa réponse sous différentes conditions d’essais. Dans la littérature, on retrouve les divers modèles développés tels que les modèles de mémoire entier et fractionnaire. L’inconvénient majeur de ces modèles est lié à la dépendance de leurs paramètres vis-à-vis des conditions d’essais, chose qui affecte le caractère général de leur représentativité des comportements quasi-statique et dynamique de la mousse polyuréthane. Pour pallier à cet inconvénient, nous avons développé des modèles qui, grâce à des choix judicieux de méthodes d’identification, assurent une représentativité plus générale des comportements quasi-statique et dynamique de la mousse polyuréthane. En effet, nous avons démontré qu’on peut exprimer les paramètres dimensionnels des modèles développés par le produit de deux parties indépendantes ; une regroupant les conditions d’essais et une autre définissant les paramètres adimensionnels et invariants qui caractérisent le matériau. Ces résultats ont été obtenus à partir de plusieurs études expérimentales qui ont permis l’appréhension du comportement quasi-statique (à travers des essais de compression unidirectionnelle) et dynamique (à travers des tests en vibration entretenue). La mousse, sous des grandes déformations, présente à la fois un comportement élastique non linéaire et un comportement viscoélastique. En outre, une discrimination entre les modèles développés particulièrement en quasi-statique a été effectuée. Les avantages et les limites de chacun y ont été discutés. / Polyurethane foam is a cellular material characterized by an interesting mechanical spectrum of properties: low density, capacity to absorb the deformation energy and low stiffness. It presents also several other properties, such as excellent thermal and acoustic insulation, high absorption of fluids and a complex scattering of light. This spectrum of properties makes polyurethane foam commonly used in many thermal, acoustic and comfort applications. To control the vibration transmitted to the seat occupants, several automatic devices for regulation and control are currently outstanding developments like active and semi-active dampers. The performance of these devices depends, of course, on the prediction of the behaviour of all the seat components and especially foam. Generally, it is essential to model the complex mechanical behaviour of polyurethane foam and identify its quasi-staticand dynamicproperties in order to optimize the design of systems with foam particularly the optimization of the comfort aspect. In this mind, the main goal of this thesis is to implement mechanical models of polyurethane foam reliable and able to provide its response under different test conditions. Several models has been developed in literature such as memory fractional and integer models. The main disadvantage of these models is the dependence of their parameters against the test conditions. It affects the general character of their representativeness to the quasi-static and dynamic behaviours of polyurethane foam. To solve this problem, we developed models with specific identification methods to ensure broader representation of the quasi-static and dynamic behaviour of polyurethane foam. Indeed, we have demonstrated that we can express the dimensional parameters of the developed models by the product of two independent parts; the first contain only the test conditions and the second define the dimensionless and invariant parameters that characterize the foam material. The developed models have been establish after several experimental studies allowing the apprehension of the quasi-static behaviour (through unidirectional compression tests) and the dynamic behaviour (through harmonic vibration tests). The polyurethane foam, under large deformations, exhibits a non linear elastic behaviour and viscoelastic behaviour. In addition, discrimination between the models developed especially in quasi-static case has been conducted. The advantages and limitations of each model have been discussed.

Os objetivos deste trabalho foram avaliar o desempenho do reator anaeróbio operado em batelada seqüencial quando submetido ao aumento progressivo da concentração de glicose e estimar os parâmetros cinéticos da degradação da glicose. Inicialmente o reator foi operado com ciclos de 8 horas, tratando glicose nas concentrações, aproximadas, de 500, 1000 e 2000 mg/L. Não foi detectada glicose no efluente nas três condições. O reator operou de maneira estável, tratando aproximadamente 500 mg/L de glicose, com eficiência na remoção da DQO filtrada entre 93% e 97%. Na operação com concentrações de glicose no afluente próximas de 1000 mg/L e 2000 mg/L, observou-se instabilidade operacional, principalmente devido à produção de polímeros extracelulares (EPS) que comprometeram a hidrodinâmica e a transferência de massa no sistema. Os valores médios da concentrações de ácidos voláteis no efluente foram de 159 ± 72 mg/L e 374 ± 92 mg/L, respectivamente. Aos perfis de concentração de glicose foi ajustado modelo de primeira ordem, enquanto que um modelo modificado, contemplando concentração residual de matéria orgânica, foi ajustado aos perfis temporais de DQO. Para verificar a formação do EPS, operou-se o reator com 3 horas de ciclo nas concentrações, aproximadas, de 500 e 1000 mg/L. Esta fase teve como objetivo verificar a hipótese, segundo a qual, a produção de EPS seria resultado da exposição da biomassa a baixas concentrações de matéria orgânica por longo período. Dessa forma, reduzindo o tempo de ciclo, a exposição a baixas concentrações também seria reduzida. No entanto, embora o reator tenha operado com relativa estabilidade, verificou-se formação de grande quantidade de EPS logo na primeira condição operacional, com aproximadamente, 500 mg/L de glicose no afluente, indicando que a hipótese não estava correta. / The main objectives of this study were to evaluate the performance of the anaerobic sequencing batch reactor when subjected to a progressive increasing of the influent glucose concentration and estimate the kinetic parameters of glucoses degradation. Initially the reactor was operated with 8-hour cycles, treating glucose at concentrations of 500, 1000 and 2000 mg/L. Glucose was not detected in the effluent in all these three conditions. The reactor showed operating stability treating glucose concentration of approximately 500mg/L, with efficiencies between 93% to 97% in the filtrated COD removal. In the operation with glucose concentrations of 1000 mg/L and 2000 mg/L, approximately, it could be noticed an operational instability, caused mainly by a production of extracellular polymers (EPS) leading to hydrodynamic and mass transfer problems in the reactor. The mean values of volatile acids concentration in the effluent were about 159 ± 72mg/L and 374 ± 92mg/L, respectively. A first order model was adjusted to glucose concentration profiles, and a modified model, including a residual concentration of substrate, was adjusted to COD temporal profiles. To verify the EPS formation, the reactor was operated with 3-hour cycle in the concentrations of 500 and 1000 mg/L This stage had the objective of verifying if the EPS production would result from the exposure of the biomass to low concentration of substrate for a long period of time. Thus, reducing the time cycle, the exposure to low concentrations would also be reduced. Nevertheless, even with the reactor operating with relative stability, the hypotheses could not be verified due the formation of a large amounts of EPS right in the first operational condition with approximately to 500 mg/L of glucose in the influent, showing that the hypothesis was not right.

Avaliou-se a influência da recirculação da fase líquida e do regime de alimentação em reator anaeróbio no tratamento de esgoto sanitário. Utilizou-se um reator anaeróbio operado em bateladas seqüenciais, contendo biomassa imobilizada (ASBBR), em escala piloto, com volume total de 1,2 \'M POT.3\' (\'fi\' 1,0 m e altura 1,53 m). O leito suporte para a imobilização da biomassa era constituído por matrizes cúbicas de espuma de poliuretano, com 5 cm de aresta, confinadas em cesto de aço inox 304, colocado no interior do reator. A influência da recirculação da fase líquida sobre o desempenho do ASBBR quanto à remoção de matéria orgânica e quanto ao arraste de sólidos foi avaliada submetendo-se o reator às velocidades ascensionais de 1,27; 3,82; 7,64 e 10,18 m/h resultantes das diferentes vazões de recirculação impostas. Contrariamente ao observado em pesquisas anteriores em reatores operados em escala de bancada e alimentados com água residuária sintética, não houve aumento significativo da eficiência do reator com o aumento da velocidade ascensional no tratamento de esgoto sanitário. A influência do regime de alimentação de esgoto sanitário no desempenho do ASBBR foi avaliada submetendo-se o reator a tempos de enchimento correspondentes a 0,25 e 0,5 do tempo total de ciclo, utilizando-se a vazão de recirculação de 6 \'M POT.3\'/h, que foi a que apresentou os melhores resultados nos ensaios anteriores. Concluiu-se que o reator pode ser operado sob batelada alimentada com duração de até 0,5 tempo de ciclo, sem que seu desempenho seja significativamente alterado. Esse resultado é importante, pois representa que o sistema de tratamento composto por reatores ASBBR pode ser projetado com número menor de reatores. A fim de esclarecer dúvidas sobre o desempenho do ASBBR observado no tratamento de água residuária de composição complexa (esgoto sanitário), o reator foi alimentado com água residuária facilmente degradável (etanol). O desempenho do reator foi aquém do esperado, mesmo quando alimentado com composto de fácil degradação. Os ensaios de atividade metanogênica específica (AME) demonstraram que houve decréscimo dos valores de AME com o aumento da velocidade ascensional. Os valores obtidos foram 0,0632; 0,0509; 0,0248 e 0,0299 g DQO-CH4/(g STV.d), respectivamente, para os valores de Va de 1,27; 3,82; 7,64 e 10,19 m/h. Concluiu-se que a baixa eficiência de remoção de matéria orgânica deveu-se ao abaixamento progressivo da atividade metanogênica do lodo, cujas causas não puderam ser completamente esclarecidas nesta pesquisa. / The influence of the liquid phase recirculation and the feeding regimen on the performance of an anaerobic sequencing batch reactor containing immobilized biomass (ASBBR) applied for the treatment of domestic sewage was evaluated. Biomass immobilization was provided by a basket containing cubic polyurethane foam matrices (5 cm side) inside the 1.2 \'M POT.3\' (1.0 m diameter and 1.53 m height) pilot-scale reactor. The influence of the liquid phase recirculation on the reactor performance in respect to organic matter and solids wash-out was verified by subjecting the reactor to a wide range of up flow velocities (1.27; 3.82; 7.64 and 10.18 m/h) resulting from different recirculation flow rates imposed. The increase of the up flow velocity did not increase the efficiency of the pilot reactor as expected. This result contradicts those obtained with bench-scale ASBBR experiments treating synthetic wastewaters. The influence of the feeding regimen was verified by subjecting the reactor to feeding times correspondent to 0.25 and 0.50 of the total cycle time, at the recirculation flow rate of 6 \'M POT.3\'/h. It could be concluded that the reactor can be operated at the feeding batch mode up to 0.5 of the cycle time. This result is important for full scale applications considering that a treatment system composed of ASBBR reactors can be designed using a lower number of units. In order to clear some aspects related to the limited performance of the ASBBR reactor treating a complex wastewater (sewage), the reactor was subjected to an easily degradable wastewater (ethanol). However, the performance was not improved even when the reactor was treating an easily degradable compound. The results from the specific methanogenic activity (SMA) demonstrated a decrease on the values of SMA with the increase of the up flow velocity. The values of SMA were 0.0632; 0.0509; 0.0248 and 0.0299 g DQO-CH4/(g STV.d) for the Va of 1.27; 3.82; 7.64 and 10.19 m/h respectively. It could be concluded that the low efficiency obtained for organic matter removal was due mainly to the progressive decrease of the sludge methanogenic activity. The causes for that behaviour could not be completely explained in this research. It could be concluded that the reactor performance was iv clearly limited by the low productivity of the methanogenic populations present in the biomass.