An interdisciplinary study concerning the durability of adhesively elastomer/metal bonded joints in marine environments is reported. The generation of OH⁻ ions at the bondline due to an imposed cathodic current from an external source is suspected to be the predominant cause of failure. A surface analysis study was performed early in this research for the purpose of identifying the cause(s) of failure. Characterization of the rubber and the metal failure surfaces with XPS (X-ray Photoelectron Spectroscopy) showed similar composition on both sides and to that of the bulk degraded primer component of the adhesive. Saponification of the adhesive and the leaching of chlorine (forming HCI that attacks the oxide) are identified as two possible failure mechanisms. The locus of failure is believed to be very close to the . adhesive/oxide interface. The exposure of bulk adhesive free-standing films to different environments showed that the hydroxyl is detrimental in the environmental durability of these specimens judging by the percentage of net mass uptake. An alternate interfacial failure mechanism is also presented where the neutralization of the adhesion-promoting attachment sites (A.S.) at the interface leads to de-adhesion and whereby OH⁻ ions chemically break-up the -COOH-Fe bond forming a non-operative activated complex at the degraded crack tip. Debond, or loss of adhesion, can exist in two modes. Weakening denotes debond growth which takes place undetected to the naked eye, and is governed by a diffusion-control degradation process that gives a straight line when plotted against the square root of time. Delamination, on the other hand, is a "post weakening" process., Debond rates in this mode are influenced by the applied total strain energy release rate, G_T, and by the environment and can be described by an exponential function in G_T. The effect of shear stress on debond acceleration was determined to be minimal. While compressive stresses seem to be beneficial in slowing the ingression of the bulk hydroxyl into the bondline, no noticeable improvement was detected when an imposed current was used. The use of zinc phosphate-coated steel substrates is shown to improve bond durability significantly at low voltages. Similar trends are observed when silane (γ-aminopropyltrimethoxy) modified primer were used in bonding. Two approaches are used in order to model debonding: empirical and analytical. Statistical Analysis System (SAS) is used to fit the empirical model which draws heavily on the functional dependencies of debond rates on the accelerating parameters, i.e., temperature, stress, and applied voltage. An Arrhenius relationship is shown to model the effect of temperature very well. Also, voltage effect is correlated with the corresponding current densities which, in turn, were found to obey an exponential relationship with debond rates. SAS fits of the experimental data are shown to model the process accurately and could be utilized for life predictions. Integration of delamination rates in real time is a feasible method to predict durability as well. A generalized analytical model for debonding is also developed, and it draws on the similarities between this application and corrosion fatigue of metals. The model is based on the conservation of mass of the involved species and is composed of a system of partial equations and their associated boundary conditions. Furthermore, temperature and voltage-dependent diffusion coefficients and reaction rate constants were used. The resulting boundary value problem amounts to a diffusion-chemical reaction mechanism into which a mechano-chemical failure mechanism is incorporated. A simplified version of the full scale analytical model is solved numerically and some interesting conclusions concerning the failure criterion are drawn. The model also simulates the weakening and delamination behavior and allows for temperature and voltage treatment as well. Delay times are also predicted as a function of the applied voltage and temperature. A particularly important conclusion is that the "marching boundary" phenomena seems to account for most of the accelerating influence of applied G. / Ph. D.

Existing closed form solutions for the stress analysis of the single lap joint were studied intensively, and methods of analysis and assumptions between the analyses of Goland and Reissner, Hart-Smith and Delale and Erdogan were compared. The existing SAAS3V finite element program was modified to accommodate additional mesh generation and plotting capabilities. The modified version, SAAS3VP, was used for performing linear elastic and viscoelastic analyses on the single lap joint, and a non-linear viscoelastic analysis on the thick adherend specimen. Metlbond 1113 and Araldite adhesive properties were used in the linear elastic and viscoelastic analyses, respectively. FM-73 adhesive properties were used in the non-linear viscoelastic analysis. Time-dependent shear moduli were calculated from the results of the latter analysis and compared with the experimentally obtained shear modulus of Krieger. Interface layers were defined in both the single lap and thick adherend analyses and the influence of changing the interface layer stiffness on adhesive stresses was also investigated. / M.S.

Ball Grid Array (BGA) solder joints are an array of solder alloy spheres sandwiched between package substrate and printed circuit board (PCB). These solder joints provide electrical connections and mechanical integrity to the assembly of package and PCB. Upcoming advanced packaging applications will involve heavier components, higher service temperatures and higher current densities, which will result in additional stresses on BGA joints accelerating their failure. Additionally, mismatch in the coefficient of thermal expansion (CTE) between the substrate, solder balls and PCB results in fracture near the solder-substrate interface posing a reliability risk. Moreover, higher current densities at elevated temperatures, also aggravate electromigration (EM) failure. It is important to mitigate these reliability risks associated with accelerated thermal cycling (ATC) and high current density EM. In this dissertation, various approaches to improve the ATC and EM reliability of packages have been investigated. First, BGA solder alloy composition was modified by doping Bi in the conventionally used Sn-3.0Ag-0.5Cu (SAC305) and Sn-4.0Ag-0.5Cu (SAC405) alloys to improve the mechanical strength of the solder joints. The effect of 1-3% Bi doping on aging induced changes in hardness, creep strength, tensile strength, viscoplasticity and microstructure was studied. Second, a reliability improvement measure (RIM) to mitigate fatigue failure of BGA solder joints was investigated. The microstructures of solder joints subjected to ATC were investigated for fatigue fractures and recrystallization of grains. Third, RIM measures to prevent EM failure of packages caused by high current density were investigated. The ability of novel substrate designs in prolonging time to failure of solder joints in packages along with EM failure mechanisms have been discussed. This dissertation thus provides insights on the efficacy and mechanisms of various reliability improvement measures to mitigate the ATC and EM reliability risks in BGA solder joints to guide future packaging design.

Nos eqüinos, as articulações sinoviais são submetidas a graus variáveis de estresse físico, de acordo com o tipo de movimento executado. Com o trabalho ou treinamento intenso, o aumento da carga imposta aos seus tecidos pode provocar sinovite mecanicamente induzida, com produção e liberação de citocinas, e conseqüentemente estimulação de metaloproteinases e de outros componentes inflamatórios. Estes eventos podem acarretar em desequilíbrio entre os processos de síntese e degradação de proteoglicanos e glicosaminoglicanos da matriz cartilagínea, levando a osteoartrite. Perante a magnitude de ocorrência de osteoartrite em eqüinos atletas, teve-se como objetivo caracterizar a população de cavalos, com diagnóstico firmado de osteoartrite, atendida junto ao Serviço de Clínica Médica de Eqüinos do Hospital Veterinário (HOVET) da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo (FMVZ/USP), em um período de 10 anos. O levantamento da casuística foi executado através da análise de fichas de registro dos casos antigos. A amostragem foi composta envolvendo a totalidade de casos de eqüídeos, com diagnóstico firmado da doença articular, arrolando-se e analisando-se dados referentes a: espécie, idade, sexo, peso, raça, atividade esportiva, início e evolução da doença, tipo de manifestação clínica, e exames radiográficos. Foram analisados 152 prontuários de eqüídeos acometidos por osteoartrite. Observou-se que a maioria tratava-se de animais da espécie eqüina, com idade média de 8 anos, macho ou fêmea, das raças Quarto de Milha, Mangalarga Paulista e sem raça definida, pesando em torno de 420kg, praticantes de romaria ou provas de Quarto de Milha.O tempo médio entre o início da sintomatologia de osteoartrite e o atendimento hospitalar foi de 7,7 meses.A análise estatística não mostrou relação entre presença de claudicação, dor palpável, sensibilidade em casco, sensibilidade muscular, teste de flexão positiva e atividade exercida (p>0,05). Porém, mostrou correlação entre a presença de edema/calor e atividade exercida (p<0,05). Também não mostrou relação entre dor palpável, edema/calor, sensibilidade de casco, sensibilidade muscular, e claudicação (p>0,05). Mediante os resultados obtidos pela avaliação radiográfica dos pacientes acometidos por osteoartrite, notou-se que não houve relação direta entre o menor e maior escore em relação à presença ou não de claudicação. Concluiu-se que o perfil do paciente, acometido por osteoartrite, mais freqüentemente atendido pelo Serviço de Clínica Médica de Eqüinos ? HOVET ? USP trata-se da espécie eqüina, da raça Quarto de Milha, 8 anos de idade, 420 kg, praticante de provas de Quarto de Milha. / The equine sinovial joints are submitted do different degrees of physical stress, depending on the movement performed. With work and hard training, the increase on the loads applied to its tissues maycause mechanically induced synovitis, with production and release of cytokines, and consequently metalloproteinases stimulation and other inflammatory components. These events may lead to anunbalance between the synthesis and degradation processes, of proteoglycan and glicosaminoglycan of the cartilaginous matrix, leading to the osteoarthritis. Regarding the magnitude of the osteoarthritis incidence on athletic horses, our goal is to characterize the horse population with confirmed osteoarthritis diagnoses examined by the Equine Internal Medicine Service at the Veterinary Hospital at the College of Veterinary Medicine and Animal Science of University of São Paulo, in a 10 year period. The retrospective study was performed through the analysis of documented cases. The sampling included the totality of equide cases with confirmed joint disease diagnosis and analyzed considering: age, sex, breed, sportive activity, beginning and evolution of the disease, clinical signs observed and radiographic exam. One hundred and fifty two (152) equides hospital forms with confirmed osteoarthritis were analyzed .It was found that most cases were equines, with an average age of 8 years, either male or female, with the predominance of Quarter Horses, Mangalarga Paulista and Mixed Breds, weighing around 420Kg, used for long distance rides or western activities. The average time between the beginning of the osteoarthritis clinical signs and the referring to the hospital was 7,7 months. The statistical analysis did not show relation between lameness, palpable pain, hoof sensitivity, muscular pain, positive flexion test and use (p>0,05). Although, its howed a relation between edema /heat and use (p<0,05). No relation was found between palpable pain, edema/heat, hoof and muscular pain and lameness (p<0,05). The results found in the radiographic evaluation of the animals with osteoarthritis showed no direct relation between the radiographic score and lameness. The animals with osteoarthritis more frequently sent to the Equine Internal Medicine Service -HOVET-USP, is equine , Quarter Horse, 8 years old, 420Kg, used in western competitions.

As estruturas de madeira composta com alma em compensado já vem sendo amplamente utilizadas em diversos países onde as estruturas de madeira estão tecnologicamente mais desenvolvidas, oferecendo aos engenheiros civis mais uma opção de sistema construtivo eficiente, seguro e duradouro. Nesse trabalho são apresentados estudos teóricos e experimentais referentes às estruturas de madeira compostas utilizando compensado nas almas, e em especial as estruturas cuja ligação alma mesa é feita por pinos metálicos. O objetivo desse trabalho é desenvolver critérios de dimensionamento dessas estruturas para serem aplicados no Brasil. Vários critérios de dimensionamento de elementos compostos foram encontrados na bibliografia, alguns com simplificações que desconsideram efeitos de composição parcial e outros mais completos, que consideram deformações por cisalhamento, composição parcial etc. Com os resultados dos ensaios de vigas compostas pregadas foi possível comparar valores experimentais com resultados teóricos, concluiu-se que os critérios de dimensionamento do EUROCODE 5 são adequados. Os ensaios de rigidez de nó de pórtico de seção composta permitiram o desenvolvimento de metodologia para o cálculo da rigidez dessas ligações, visto que não existe formulação equivalente na bibliografia internacional. Concluiu-se que as ligações por pinos metálicos apresentam boa eficiência para serem utilizadas nas seções compostas com alma em compensado. As ligações de nó de pórtico com ligação alma/mesa pregadas podem ser consideradas rígidas na maioria dos casos estudados. / Plywood webbed structures have been applied in at several countries where timber structures are commonly used, giving civil engineers and builders one more option when looking for a safe, efficient and durable construction system. This work presents theoretical and experimental studies about plywood-webbed structures, with emphasis on nailed plywood webbed structures. The aim of this work is to develop design criteria for these structures to be used in Brazil. Several design criteria where found in the bibliography, some of them using simplifications for shear deflexions and joint deformations. Experimental results of nailed plywood webbed beams were compared with theoretical values from formulations found in the bibliography, concluding that EUROCODE 5 gives the best design criteria for nailed composite beams. Based on plywood webbed knee joints tests, a methodology to calculate the joint rigidity was proposed. The conclusions show the efficiency of this system and that nailed plywood webbed knee joints can be considered fixed for the majority of the specimens tested.

Motivated by the interests to understand bio-structure deformation and exploit their advantages to create bio-inspired systems for engineering applications, a curvature-based model for analyzing compliant mechanisms capable of large deformation in a three dimensional space has been developed. Unlike methods (such as finite element) that formulate problems based on displacements and/or rotational angles, superposition holds for curvatures in the case of finite rotation but not for rotational angles; thus the curvature-based formulation presents an advantage in presenting nonlinear geometries. Along with a generalized constraint that relaxes traditional boundary constraints (such as fixed, pinned or sliding constraint) on compliant mechanisms, the method of deriving the compliant members in the same global referenced frame is presented. The attractive features of the method, which greatly simplifies the models and improves the computation efficiency of multi-body system deformation where compliant beams play an important role, have been experimentally validated. To demonstrate the applicability of this proposed method to a broad spectrum of applications, three practical examples are given; the first example verifies the generalized constraint by analyzing the multi-axis rotation motion within a natural human knee joint and investigates the human-exoskeleton interactions through dynamic analysis. The second example studies a deformable bio-structure by incorporating the generalized joint constraint into the curvature-based model for automated poultry meat processing. The last example designs a bio-inspired robot with a compliant mechanism to serve as a flexonic mobile node for ferromagnetic structure health monitoring. The analytical models have been employed (with experimental validation) to investigate the effects of different joint constraints on the mechanism deformations. It is expected that the proposed method will find a broad range of applications involving compliant mechanisms.

As estruturas de madeira composta com alma em compensado já vem sendo amplamente utilizadas em diversos países onde as estruturas de madeira estão tecnologicamente mais desenvolvidas, oferecendo aos engenheiros civis mais uma opção de sistema construtivo eficiente, seguro e duradouro. Nesse trabalho são apresentados estudos teóricos e experimentais referentes às estruturas de madeira compostas utilizando compensado nas almas, e em especial as estruturas cuja ligação alma mesa é feita por pinos metálicos. O objetivo desse trabalho é desenvolver critérios de dimensionamento dessas estruturas para serem aplicados no Brasil. Vários critérios de dimensionamento de elementos compostos foram encontrados na bibliografia, alguns com simplificações que desconsideram efeitos de composição parcial e outros mais completos, que consideram deformações por cisalhamento, composição parcial etc. Com os resultados dos ensaios de vigas compostas pregadas foi possível comparar valores experimentais com resultados teóricos, concluiu-se que os critérios de dimensionamento do EUROCODE 5 são adequados. Os ensaios de rigidez de nó de pórtico de seção composta permitiram o desenvolvimento de metodologia para o cálculo da rigidez dessas ligações, visto que não existe formulação equivalente na bibliografia internacional. Concluiu-se que as ligações por pinos metálicos apresentam boa eficiência para serem utilizadas nas seções compostas com alma em compensado. As ligações de nó de pórtico com ligação alma/mesa pregadas podem ser consideradas rígidas na maioria dos casos estudados. / Plywood webbed structures have been applied in at several countries where timber structures are commonly used, giving civil engineers and builders one more option when looking for a safe, efficient and durable construction system. This work presents theoretical and experimental studies about plywood-webbed structures, with emphasis on nailed plywood webbed structures. The aim of this work is to develop design criteria for these structures to be used in Brazil. Several design criteria where found in the bibliography, some of them using simplifications for shear deflexions and joint deformations. Experimental results of nailed plywood webbed beams were compared with theoretical values from formulations found in the bibliography, concluding that EUROCODE 5 gives the best design criteria for nailed composite beams. Based on plywood webbed knee joints tests, a methodology to calculate the joint rigidity was proposed. The conclusions show the efficiency of this system and that nailed plywood webbed knee joints can be considered fixed for the majority of the specimens tested.

Nos eqüinos, as articulações sinoviais são submetidas a graus variáveis de estresse físico, de acordo com o tipo de movimento executado. Com o trabalho ou treinamento intenso, o aumento da carga imposta aos seus tecidos pode provocar sinovite mecanicamente induzida, com produção e liberação de citocinas, e conseqüentemente estimulação de metaloproteinases e de outros componentes inflamatórios. Estes eventos podem acarretar em desequilíbrio entre os processos de síntese e degradação de proteoglicanos e glicosaminoglicanos da matriz cartilagínea, levando a osteoartrite. Perante a magnitude de ocorrência de osteoartrite em eqüinos atletas, teve-se como objetivo caracterizar a população de cavalos, com diagnóstico firmado de osteoartrite, atendida junto ao Serviço de Clínica Médica de Eqüinos do Hospital Veterinário (HOVET) da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo (FMVZ/USP), em um período de 10 anos. O levantamento da casuística foi executado através da análise de fichas de registro dos casos antigos. A amostragem foi composta envolvendo a totalidade de casos de eqüídeos, com diagnóstico firmado da doença articular, arrolando-se e analisando-se dados referentes a: espécie, idade, sexo, peso, raça, atividade esportiva, início e evolução da doença, tipo de manifestação clínica, e exames radiográficos. Foram analisados 152 prontuários de eqüídeos acometidos por osteoartrite. Observou-se que a maioria tratava-se de animais da espécie eqüina, com idade média de 8 anos, macho ou fêmea, das raças Quarto de Milha, Mangalarga Paulista e sem raça definida, pesando em torno de 420kg, praticantes de romaria ou provas de Quarto de Milha.O tempo médio entre o início da sintomatologia de osteoartrite e o atendimento hospitalar foi de 7,7 meses.A análise estatística não mostrou relação entre presença de claudicação, dor palpável, sensibilidade em casco, sensibilidade muscular, teste de flexão positiva e atividade exercida (p>0,05). Porém, mostrou correlação entre a presença de edema/calor e atividade exercida (p<0,05). Também não mostrou relação entre dor palpável, edema/calor, sensibilidade de casco, sensibilidade muscular, e claudicação (p>0,05). Mediante os resultados obtidos pela avaliação radiográfica dos pacientes acometidos por osteoartrite, notou-se que não houve relação direta entre o menor e maior escore em relação à presença ou não de claudicação. Concluiu-se que o perfil do paciente, acometido por osteoartrite, mais freqüentemente atendido pelo Serviço de Clínica Médica de Eqüinos ? HOVET ? USP trata-se da espécie eqüina, da raça Quarto de Milha, 8 anos de idade, 420 kg, praticante de provas de Quarto de Milha. / The equine sinovial joints are submitted do different degrees of physical stress, depending on the movement performed. With work and hard training, the increase on the loads applied to its tissues maycause mechanically induced synovitis, with production and release of cytokines, and consequently metalloproteinases stimulation and other inflammatory components. These events may lead to anunbalance between the synthesis and degradation processes, of proteoglycan and glicosaminoglycan of the cartilaginous matrix, leading to the osteoarthritis. Regarding the magnitude of the osteoarthritis incidence on athletic horses, our goal is to characterize the horse population with confirmed osteoarthritis diagnoses examined by the Equine Internal Medicine Service at the Veterinary Hospital at the College of Veterinary Medicine and Animal Science of University of São Paulo, in a 10 year period. The retrospective study was performed through the analysis of documented cases. The sampling included the totality of equide cases with confirmed joint disease diagnosis and analyzed considering: age, sex, breed, sportive activity, beginning and evolution of the disease, clinical signs observed and radiographic exam. One hundred and fifty two (152) equides hospital forms with confirmed osteoarthritis were analyzed .It was found that most cases were equines, with an average age of 8 years, either male or female, with the predominance of Quarter Horses, Mangalarga Paulista and Mixed Breds, weighing around 420Kg, used for long distance rides or western activities. The average time between the beginning of the osteoarthritis clinical signs and the referring to the hospital was 7,7 months. The statistical analysis did not show relation between lameness, palpable pain, hoof sensitivity, muscular pain, positive flexion test and use (p>0,05). Although, its howed a relation between edema /heat and use (p<0,05). No relation was found between palpable pain, edema/heat, hoof and muscular pain and lameness (p<0,05). The results found in the radiographic evaluation of the animals with osteoarthritis showed no direct relation between the radiographic score and lameness. The animals with osteoarthritis more frequently sent to the Equine Internal Medicine Service -HOVET-USP, is equine , Quarter Horse, 8 years old, 420Kg, used in western competitions.

M.Ing. / This research project was initiated by a well-known international company (MAKRO SA), which had experienced floor joint problems occurring in their industrial floors. Floor joint problems i.e. joint damage and spalling of the joint area result, from a combination of construction workmanship and quality control problems, as well as from operational hard wheeled vehicle loading conditions. Damaging and spalling of joint edges are general problems occurring on warehouse floor slabs because of hard wheeled loads trafficking joints. In addition, joint filler detachment from the joint wall surface looks aesthetically poor and leaves the possibility of hygienic problems developing. In the case of MAKRO SA stores, the above problems are not acceptable and should be avoided at all costs. The objective of the report is to investigate solutions to solve the problem of joint damage in industrial floors due to problems occurring in practice, as described below. Floor joint edge problems are a result of three main reasons. First, subsoil quality. The quality of the subsoil is determined by the compaction effort and type of filler materials used, which in turn determine the amount of deflection that will be detected at joint edges. Subgrade quality determines whether deflection of the top concrete layer will occur. Poor compaction and filler material contributes to excessive deflection occurring due to inadequate support of the concrete floor slabs. Water penetration through the floor slab results in the fines of the subsoil being eroded or washed out, resulting in a less dense material, which will deflect under large vehicle and store racking loads. It is concluded that good quality subsoil conditions will result in less deflection and level irregularities of the top concrete floor slab, resulting in less joint damage and spalling. Secondly, the effect of floor and joint workmanship on damage and joint edge spalling. Level irregularities occur due to poor troweling or floating efforts at the joint area. Poor joint edge workmanship results from incorrect formwork removal from the joint wall resulting in a damaged joint edge and additional spalling of the joint to that occurring from wheel load impact. Joints undergo damage as forklifts traffic the joint area as wheel load and energy

Des tests de fissuration ont été réalisés sur des joints collés asymétriques. Ces assemblages asymétriques sont constitués de deux substrats de nature et/ou d’épaisseur différentes liés par un adhésif. Cette géométrie d’éprouvette semble peu utilisée pour effectuer des essais de fissuration. Elles présentent certains inconvénients et de ce fait n’ont fait l’objet d’aucune normalisation. Dans le cadre cette géométrie d’éprouvette d’essai a été néanmoins été retenue et utilisée dans trois configurations différentes pour la caractérisation mécanique des assemblages collés. Des protocoles d’essai et les schéma d’analyse associés ont été définis pour des essais de fissuration à vitesse de déplacement imposé (CRT : Constant Rate Test), à force imposée (CFT : Constant Force Test) ainsi qu’à déplacement imposé (CDT : Constant Displacement Test). Les analyses ont pu être étalonnées au moyen d’un étau matérialisant artificiellement la position d’un fissure. De nombreuses configurations ont été étudiées à l’occasion de ce travail tant du point de vue des adhésifs utilisés (epoxy, cyanoacrylate, acrylic mastic, PSA) que du point de vue des substrats encollés (alliage d’aluminium, composite à matrice organique, polycarbonate). Ces nouveaux tests s’avèrent prometteurs car ils permettent de suivre de façon continu et précision la propagation de fissure au sein de la liaison. En outre, l’analyse des déformations mesurées par extensométrie lors d’essai réalisés à déplacement imposé (CDT) permet un suivi précis de la réponse de la couche adhésive dans la zone contrainte et d’estimer la taille de cette dernière, y compris lorsque la colle est dans un état métastable. Un autre résultat important de ce travail concerne l’analyse de la modification du front de fissure celle-ci voit une diminution de l’adhésion entre les deux substrats. Enfin, un calcul plus précis du taux de restitution d’énergie a été proposé pour prendre en compte le caractère élastique de la couche adhésive, mais permettant aussi de mieux appréhender la redistribution des contraintes dans la colle, et ainsi mieux interpréter les essais mécaniques réalisés. Des analyses par Microscopie à Force Atomique (AFM) ainsi qu’au microscope électronique à balayage (MEB) ont été effectués sur les substrats encollés pour évaluer l’impact des traitements de surface. Des simulations numériques par la method des éléments finis ont été réalisées pour determiner l’état de contrainte dans nos éprouvette d’essai et ainsi expliquer la courbure du front de fissure et les faciès de rupture observés. Les nouvelles configurations expérimentales décrites dans ce manuscript nous paraissent prometteuses car elle offrent une amelioration très significative en terme de fiabilité et précision comparativement aux tests présentés habituellement pour ce type de travaux. / Adhesion was studied in asymmetric bonded joints using fracture mechanics tests. The asymmetric bonded joints consist of two different type and/or thickness materials bonded by an adhesive. Mentions of asymmetric bonded joint tests employed so far are rare in the literature. They are imperfect and therefore are not standardized. Accordingly three new tests were introduced in this work to study bonded joints. The new metrological routines and models were built for the CRT (Constant Rate Test), CFT (Constant Force Test) and the CDT (Constant Displacement Test). The routines were validated with the new Artificial Crack Tip test developed in this thesis. Different bonded systems were examined: the adhesives - epoxy, cyanoacrylate, acrylic mastic, PSA; the bonded adherends - aluminium alloys, CFRP composites and polycarbonate. The results obtained in the new tests are very promising in terms of the accuracy and continuous observation of crack kinetics. In addition it was found that the novel strain gauge technique, introduced in the CDT, test allows precise joint monitoring when the adhesive is in a metastable state and a precise estimation of process zone. Another interesting achievement of this work was describing the phenomenon of double crack curvature in the vicinity of the strong – weak adhesion transition zone. The next achievement was derivation of the strain energy release rate from the elastic foundation model, which gives better understanding of the mechanics and the measurements behind adhesive bonding. Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) studies were made of the bonded substrates to estimate the surface treatment effects. The stress state in asymmetric geometry was studied using finite element analysis (FEA), which explained the formation of the curved crack front and the origin of river patterns. The new tests developed in this study appear promising since they offer accurate and reliable results for the materials tested. / W pracy przedstawiono wyniki badan asymetrycznych zlaczy adhezyjnych z wykorzystaniem prób mechaniki pekania. Asymetryczne zlacza klejone powstaja przez polaczenie dwóch dowolnych materialów, o innym wskazniku na zginanie, za pomoca kleju. Zaproponowano trzy nowe metody eksperymentalne dla których zaprojektowano i zbudowano stanowiska badawcze. Poprawnosc modeli fizycznych i matematycznych wykorzystanych do interpretacji badanych zjawisk potwierdzono wykorzystujac opracowana w pracy próbe ze sztucznym frontem pekniecia. Próby przeprowadzono na zlaczach klejonych wykorzystujac kleje: epoksydowe, cjanoakrylowy, typu Mastic i PSA, laczonymi materialami byly: stopy aluminium, kompozyt weglowy oraz poliweglan. Wyniki badan uzyskane przy wykorzystaniu nowych metod wskazuja na ich pewnosc i dokladnosc, dodatkowo umozliwiaja ciagla obserwacje propagujacego pekniecia. Nowa metoda pomiaru parametrów mechaniki pekania oparta na pomiarach tensometrycznych zostala z powodzeniem zastosowana do zlaczy w których klej znajduje sie w stanie metastabilnym. W pracy zaobserwowano i przeanalizowano zjawisko powstawania podwójnego frontu pekniecia na granicy osrodków o róznych silach adhezji, dotad nie opisanego. Po raz pierwszy wyprowadzono równanie szybkosci uwalniania energii sprezystej wykorzystujac model belki na sprezystym podlozu, co umozliwia lepsze zrozumienie zachowania sie zlaczy klejonych. Przeprowadzone badania z uzyciem mikroskopii sil atomowych (AFM) oraz skaningowej mikroskopii elektronowej (SEM) umozliwily ocene efektów obróbki powierzchniowej stopów aluminium. W pracy dokonano analizy naprezen w asymetrycznych zlaczach adhezyjnych z wykorzystaniem metody elementów skonczonych (FEM). Analiza FEM pozwolila na wyjasnienie zjawiska powstawania zakrzywionego frontu pekniecia w badanych przelomach. Zaproponowane nowe metody badan zlaczy asymetrycznych zapewniaja dokladnosc i pewnosc pomiaru dla materialów wykorzystanych w badaniach.