The random discontinuous fiber composite has uniform properties in all directions. The wetlay process is an efficient method to manufacture random discontinuous thermoplastic preform sheets that can be molded into random composite plaques in the hot-press. Investigations were done on the molding parameters that included the set-point mold pressure, set-point mold temperature and cooling methods. The fibers used in the study included glass and carbon fiber. Polypropylene (PP) and Polyethylene Terephthalate (PET) were used as the matrix. Glass/PP and Glass/PET plaques that had fiber volume fractions ranging from 0.05 to 0.50 at an increment of 0.05 were molded. Both tensile and flexural tests were conducted. The test results showed a common pattern, i.e., the modulus and strength of the composite increased with the fiber volume fraction to a maximum and then started to descend. The test results were analyzed to find out the optimal fiber volume fraction that yielded the maximum modulus or strength. Carbon/PET composites plaques were also molded to compare their properties with Glass/PET composite at similar fiber volume fractions. Micrographs were taken of selected specimens to examine the internal structure of the material. Existing micromechanics models that predict the tensile modulus or strength of random fiber composites were examined. Predictions from some of the models were compared with test data. / Master of Science

The microstructure and mechanics of collagen and elastin protein fiber networks dictate the mechanical responses of all soft tissues and related organ systems. In this project, we endeavored to meet or exceed native tissue mechanical properties through mimicry of these extracellular matrix components with synthetic collagen fiber and elastin analogues. Significantly, these studies led to the development of a framework for the design and fabrication of protein-based soft tissue substitutes that reproduced many aspects of native biomechanics. A scalable process was developed for production of synthetic collagen microfibers at a rate of 60 m/hr. Fiber properties and ultrastructure were characterized by uniaxial mechanical testing, differential scanning calorimetry, transmission electron microscopy, and second harmonic generation analysis. In vivo responses to synthetic fibers were evaluated in a murine model. A scalable, semi-automated process was designed for the fabrication of multilamellar membranes comprised of sheets of an elastin analogue reinforced with synthetic collagen fibers. Fibers could be organized in a precisely defined three-dimensional hierarchical pattern. The structure of these fiber composites was analyzed by scanning and transmission electron microscopy, and digital volumetric imaging. The effects of fiber orientation and volume fraction on uniaxial mechanical responses were evaluated. Increased fiber volume fraction and alignment increased Young's modulus, resilience, and yield stress. Highly extensible, elastic tissues display a functionally significant transition from low to high modulus deformation at a transition point strain dictated by the crimped collagen microstructure. This response was replicated by the fabrication of dense arrays of microcrimped synthetic collagen fibers embedded in an elastin analogue. The degree of microcrimping could be varied, and generated a transition point mechanical response. Cyclic tensile deformation did not substantially alter microcrimp morphology. A series of small-diameter vascular grafts consisting of an elastin-like protein reinforced with controlled volume fractions and orientations of synthetic collagen fiber was designed and prototyped. The optimal design satisfied target properties with suture retention strength of 173 ± 4 g-f, burst strength of 1483 ± 143 mm Hg, and compliance of 5.1 ± 0.8 %/100 mm Hg.

The dynamics of fiber orientation is of great interest for efforts to predict the microstructure and material properties of a suspension flow system. In this research a fiber-level, hybrid simulation method, LBM‒EBF (coupled lattice‒Boltzmann method with the external boundary force method) is undertaken to advance the current understanding of the hydrodynamic interaction induced rotational diffusion mechanism for rigid fibers in semidilute suspension of low Reynolds number flow. The LBM‒EBF simulations correctly predict the orbit constant distribution of fibers in a sheared semidilute suspension flow. It is demonstrated that an anisotropic, weak rotary diffusion model can fit the orbit constant distribution very well, but it can not describe the asymmetry in Stokes flow observed in semidilute suspension. The rotational diffusion process is then characterized with a three dimensional spatial tensor representation of the rotational diffusivity. A scalar measure of the rotational diffusion‒'scalar Folgar‒Tucker constant', C[subscript I], is extracted from this tensor. The study provides substantial numerical evidence that the range of C[subscript I] (0.0038 to 0.0165) obtained by Folgar&Tucker (J. reinf. plast. and comp, v.3, 1984) in a semidilute regime is overly diffusive, and that the correct magnitude is of O(10⁻⁴). The study reveals that the interactions among fibers become more frequent with either the decrease of fiber aspect-ratio, r[subscript p] (keeping nL³ constant, where n is the fiber number density, and L is the fiber length) or with the increase of nL³ (keeping r[subscript p] constant) in the semidilute regime, which in consequence causes an increase in C[subscript I]. The rheological properties of sheared semidilute suspension are also computed with direct LBM‒EBF simulations. The LBM‒EBF investigation is extended to characterize the fiber orientation in a linearly contracting channel similar to a paper machine 'headbox'. It is found that the rotational diffusion is the predominant term over the strain rate in the semidilute regime for a low Reynolds number flow, and it results in a decreasing trend of rotational Peclet number, Pe, along the contraction centerline. Lastly, in order to improve the numerical consistency of the existing LBM‒EBF approach, a modification to the body force term in the LB equation is suggested, which can recover the exact macroscopic hydrodynamics from the mesoscale.

No description available.

Predicting the effective elastic properties of a composite material based on the elastic properties of the constituent materials is extremely difficult, even when the microstructure is known. However, there are cases where certain properties in constituents always carry over to a composite, regardless of the microstructure of the composite. We call such instances exact relations. The general theory of exact relations allows us to find all of these instances in a wide variety of contexts including elasticity, conductivity, and piezoelectricity. We combine this theory with ideas from representation theory to find all exact relations for fiber-reinforced polycrystalline composites. We further extend these ideas to the concept of links. When two composites have the same microstructure but different constituent materials, their effective tensors may be related. We use the theory of exact relations to find such relations, which we call links. In this work we describe a special set of links between elasticity tensors of fiber-reinforced polycrystalline composites. These links allow us to generalize certain results from specific examples to generate new information about this widely-used class of composites. In particular, we apply the link to obtain information about composites made from two transversely isotropic materials and polycrystals made from one orthotropic material. / Mathematics

In this thesis, experiments and simulations are performed to study the deployment dynamics of space webs and space booms, focusing on the deployment and stabilization phases of the space web and the behavior of the bi-stable tape spring booms after long-term stowage. The space web, Suaineadh, was launched onboard the sounding rocket REXUS-12 from the Swedish launch base Esrange in Kiruna on 19 March 2012. It served as a technology demonstrator for a space web. A reaction wheel was used to actively control the deployment and stabilization states of the 2×2 m2 space web. After ejection from the rocket, the web was deployed but entanglements occurred since the web did not start to deploy at the specified angular velocity. The deployment dynamics was reconstructed by simulations from the information recorded by inertial measurement units and cameras. Simulations show that if the web would have started to deploy at the specified angular velocity, the web would most likely have been deployed and stabilized in space by the motor, reaction wheel and controller used in the experiment. A modified control method was developed to stabilize the out-of-plane motions before or during deployment. New web arms with tape springs were proposed to avoid entanglements. A deployable booms assembly composed of four 1-m long bi-stable glass fiber tape springs was designed for the electromagnetically clean 3U CubeSat Small Explorer for Advanced Missions (SEAM). The deployment dynamics and reliability of the SEAM boom design after long-term stowage were tested by on-ground experiments. A simple analytical model was developed to predict the deployment dynamics and to assess the effects of the GOLS and the combined effects of friction, viscoelastic strain energy relaxation, and other factors that act to decrease the deployment force. In order to mitigate the viscoelastic effects and thus ensure self-deployment, different tape springs were designed, manufactured and tested. A numerical model was used to assess the long-term stowage effects on the deployment capability of bi-stable tape springs including the friction, nonlinear-elastic and viscoelastic effects. A finite element method was used to model a meter-class fully coiled bi-stable tape spring boom and verified by analytical models. / <p>QC 20170508</p> / SEAM

Submitted by JÚLIO HEBER SILVA (julioheber@yahoo.com.br) on 2017-01-12T18:01:08Z No. of bitstreams: 2 Dissertação - Rodrigo Rocha Andrade - 2015.pdf: 2602785 bytes, checksum: 247e93d65c955ab4bec180868a79f2e7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-01-16T10:51:51Z (GMT) No. of bitstreams: 2 Dissertação - Rodrigo Rocha Andrade - 2015.pdf: 2602785 bytes, checksum: 247e93d65c955ab4bec180868a79f2e7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-01-16T10:51:51Z (GMT). No. of bitstreams: 2 Dissertação - Rodrigo Rocha Andrade - 2015.pdf: 2602785 bytes, checksum: 247e93d65c955ab4bec180868a79f2e7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-03-24 / Previous studies show that there is effective interaction between silanized glass fiber and resin matrix formed by methacrylates; However, there is no information on the use of milled glass fiber and the resin incorporated as a filler particle in order to obtain better mechanical properties in composites for the manufacture of intraradiculares pins. The objectives of this study were to evaluate the influence of different types (barium silicate and / or glass fiber powder) and charged particle concentrations in flexural strength, resistance to diametrical and Knoop microhardness traction, an experimental composite composed of 47.5% loading of particles, 30 % glass fiber and resin matrix of 22.5% (BISGMA and TEGDMA (1: 1)); evaluate the morphology of the filler particles and their interaction with the experimental composite in scanning electron microscopy. For producing glass fiber powder, fibers were milled in a mortar grinder / pestle, and then six experimental groups (N = 10) were prepared, varying the ratio of the kind of charged particle: CONTROL - 47.5% barium silicate and 0.0% glass fiber powder; G7.5 - 40.0% barium silicate and 7.5% glass fiber powder; G17.5 - barium silicate 30.0% and 17.5% glass fiber powder; G27.5 - barium silicate 20.0% and 27.5% glass fiber powder; G37.5% - 10.0% barium silicate and 37.5% glass powder vibrates; G47.5% - 0.0% barium silicate and 47.5% glass fiber powder. Cylindrical samples (3 mm x 6 mm) were produced for the diametral tensile strength test, and samples in bar format (25 mm x 2 mm x 2 mm) for flexural and microhardness knoop throws. Resistance tests were performed at 0.5 mm / min on a universal testing machine (Instron 5965). The Knoop microhardness test was made 0.2 KHN (200 g) for 40 seconds at a hardness tester (Shimadzu HMV2). After verification of normality and homogeneity of data distribution with the Kolmogorov-Smirnov test, the data were submitted to ANOVA and Tukey tests (α = 0.05). Statistical analysis demonstrated (p = 0.001): flexural strength: CONTROL - 259.91 ± 26.01a; G7.5 - 212.48 ± 35.91b; G17.5 - 177.63 ± 24.88bc; G27.5 - 166.58 ± 30.84c; G37.5 - 92.08 ± 6.46d; G47.5 - 80.60 ± 17.89d; Diametral tensile strength: CONTROL - 31.05 ± 2.98a; G7.5 - 14.55 ± 3.70b; G27.5 - 12.65 ± 3.34bc; G17.5 - 8.62 ± 3.51cd; G47.5 - 8.04 ± 1.63d; G37.5 - 6.63 ± 2.85d; Knoop microhardness: CONTROL - 75.69 ± 12.19a; G37.5 - 67.62 ± 1.79ab; G27.5 - 65.72 ± 2.01b; G47.5 - 64.06 ± 1.61b; G7.5 - 62.79 ± 2.79b; G17.5 - 59.87 ± 2.33b. The gradual substitution a percentage of the barium silicate glass fiber powder in a glass fiber reinforced composite trial resulted in a decrease in the results of flexural strength, diametral tensile strength and Knoop hardness. Morphologically, glass fiber powder made up of particles with heterogeneous and larger than the particle of barium silicate. The interaction of the glass fiber powder to the resin matrix and fiber reinforcement have not proved effective. / Estudos prévios demonstram haver efetiva interação entre fibra de vidro silanizada e matriz resinosa formada por metacrilatos; porém, inexiste informação sobre a utilização da fibra de vidro moída e incorporada à resina como partícula de carga, com a finalidade de obter melhores propriedades mecânicas em compósitos destinados à fabricação de pinos intraradiculares. Os objetivos deste trabalho foram: avaliar a influência de diferentes tipos (silicato de bário e/ou pó de fibra de vidro) e concentrações de partícula de carga na resistência flexural, resistência à tração diametral e microdureza Knoop, de um compósito experimental composto por 47,5 % de partículas de carga, 30 % de fibra de vidro e 22,5 % de matriz resinosa (BISGMA e TEGDMA (1:1)); avaliar a morfologia das partículas de carga e sua interação com o compósito experimental em microscopia eletrônica de varredura. Para produção do pó de fibra de vidro, fibras foram moídas em um moinho almofariz/pistilo e então seis grupos experimentais (N = 10) foram confeccionados, variando a proporção do tipo de partícula de carga: CONTROLE – 47,5 % silicato de bário e 0,0 % pó de fibra de vidro; G7,5 – 40,0 % silicato de bário e 7,5 % pó de fibra de vidro; G17,5 – 30,0 % silicato de bário e 17,5 % pó de fibra de vidro; G27,5 – 20,0 % silicato de bário e 27,5 % pó de fibra de vidro; G37,5 % - 10,0 % silicato de bário e 37,5 % pó de vibra de vidro; G47,5 % - 0,0 % silicato de bário e 47,5 % pó de fibra de vidro. Amostras cilíndricas (3 mm x 6 mm) foram produzidas para o teste de resistência à tração diametral, e amostras em formato de barra (25 mm x 2 mm x 2 mm) para os testes de resistência flexural e microdureza knoop. Os testes de resistência foram executados a 0,5 mm/min em máquina de ensaios universais (Instron 5965). O teste de microdureza knoop foi feito a 0,2 KHN (200 g) por 40 segundos em um durômetro (HMV2 Shimadzu). Após verificação de normalidade e homogeneidade de distribuição dos dados com o teste Kolmogorov-Smirnov, os dados foram submetidos aos testes ANOVA e Tukey (α=0,05). Análises estatísticas demonstraram (p=0,001): resistência flexural: CONTROLE - 259,91±26,01a; G7,5 - 212,48±35,91b; G17,5 - 177,63±24,88bc; G27,5 - 166,58±30,84c; G37,5 – 92,08±6,46d ; G47,5 – 80,60±17,89d; Resistência à tração diametral: CONTROLE – 31,05±2,98a; G7,5 – 14,55±3,70b; G27,5 – 12,65±3,34bc; G17,5 – 8,62±3,51cd; G47,5 – 8,04±1,63d ; G37,5 – 6,63±2,85d; Microdureza Knoop: CONTROLE – 75,69±12,19a; G37,5 – 67,62±1,79ab; G27,5 – 65,72±2,01b; G47,5 – 64,06±1,61b; G7,5 – 62,79±2,79b; G17,5 – 59,87±2,33b. A substituição gradativa em percentual do silicato de bário pelo pó de fibra de vidro em um compósito experimental reforçado com fibra de vidro resultou em queda nos resultados de resistência flexural, tração diametral e microdureza knoop. Morfologicamente, a partícula de pó de fibra de vidro apresentou-se heterogênea e com tamanho maior que a partícula do silicato de bário. A interação do pó de fibra de vidro com a matriz resinosa e o reforço de fibra não se mostraram efetivos.

Virtual crack closure technique (VCCT) is commonly used to analyze debonding/delamination onset and growth in fiber reinforced composite assemblies. VCCT is a computational fracture mechanics based approach, and is based on Irwin&rsquo / s crack closure integral. In this study, the debonding/delamination onset and growth potential in a bonded fiber reinforced composite skin-flange assembly is investigated using the VCCT. A parametric finite element analyses is conducted. The finite element analyses results are compared with coupon level experimental results available in the literature. The effects of different finite element modeling techniques are investigated. The bonded flange-assembly is modeled with pure solid (3D) elements, plane stress (2D) shell elements and plane strain (2D) shell elements. In addition, mesh density, element order and geometric non-linearity parameters are investigated as well. The accuracy and performance of these different modeling techniques are assessed. Finally, effect of initial defect location on delamination growth potential is investigated. The results presented in this study are expected to provide an insight to practicing engineers in the aerospace industry.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2016-09-20T11:52:54Z No. of bitstreams: 2 Dissertação - Isabella Negro Favarão - 2014.pdf: 1147871 bytes, checksum: 0e08616a9e1bff5fb2e39258564e5493 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-09-20T11:53:59Z (GMT) No. of bitstreams: 2 Dissertação - Isabella Negro Favarão - 2014.pdf: 1147871 bytes, checksum: 0e08616a9e1bff5fb2e39258564e5493 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-09-20T11:53:59Z (GMT). No. of bitstreams: 2 Dissertação - Isabella Negro Favarão - 2014.pdf: 1147871 bytes, checksum: 0e08616a9e1bff5fb2e39258564e5493 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2014-02-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The aim of this study was to characterize the mechanical properties (Flexural strength, Diametral tensile strength, Knoop hardness, Young`s modulus, and Poisson's ratio) of a new experimental composite reinforced with glass fiber, and evaluate the fracture resistance and failure mode of bovine roots post-restored with a new experimental composite produce in direct or indirect (laboratory) mode and compare them with prefabricated fiber glass posts. Experimental composite specimens (22.5% resin, 30% 3mm-short silanized glass fibers, and 47.5% of filler particles) were prepared and tested in a universal testing machine according to the particular methodology of each test, scanning electron microscopy analysis was performed on samples fractured in bending test. Thirty endodontically treated bovine roots were divided into 3 groups (n = 10): PFP: prefabricated fiber glass posts EXP-DIR: posts made of experimental material directly polymerised into the root canal EXP-IND: posts made of experimental material indirectly polymerised. Specimens were subjected to compression load (0.5 mm/min), maximum load recorded in Newton, and fracture ranked as the failure mode. Descriptive analyzes showed averages: 259.91 ± 26.01 MPa (Flexural strength); 31.05 ± 2.97 MPa (Diametral Tensile strength); 135.6 ± 24.8 KHN (Knoop Hardness), 5.6 ± 0.95 GPa (Young`s modulus), 0.34 ± 0.02 (Poisson's ratio). ANOVA and Tukey analyzes showed statistical difference for fracture resistance (p <0.05): PFP (620.72 ± 59.29)A, EXP-IND (506.54 ± 27.07)B, EXP-DIR (157.76 ± 32.34)C. The developed composite showed appropriate mechanical properties and feasibility for production of intracanal posts, however dependent on the method of production, being the indirect method the best. / O objetivo deste estudo foi caracterizar as propriedades mecânicas (Resistência à Flexão, Resistência à Tração Diametral, Dureza Knoop, Módulo de Elasticidade, e Coeficiente de Poisson) de um novo compósito experimental reforçado com fibra de vidro polimerizado de maneira convencional, e avaliar a resistência e padrão de fratura de raízes de incisivos bovinos restauradas com pinos confeccionados com o novo compósito experimental de maneira direta ou indireta (laboratorial) e compará-las com pinos de fibra de vidro pré-fabricados. Amostras do compósito experimental (22,5% de resina, 30% de fibra de vidro curta silanizada (3mm), e 47,5% de partículas de carga) foram confeccionadas e testadas em máquina de ensaio universal de acordo com a metodologia específica de cada teste; análise em Microscopia Eletrônica de Varredura foi realizada nas amostras fraturadas no teste de flexão. Trinta raízes bovinas tratadas endodonticamente foram distribuídas em 3 grupos (n=10): PFP: pino de fibra de vidro pré-fabricado; EXP-DIR: pino de fibra de vidro confeccionado com material experimental polimerizado de forma direta no canal radicular; EXP-IND: pino de fibra de vidro confeccionado com o material experimental polimerizado de forma indireta. Os espécimes foram submetidos à carga compressiva (0,5 mm/min), carga máxima registrada em Newton, e classificados quanto ao padrão de fratura. Análises descritivas demonstraram médias: 259,91±26,01 MPa (Resistência Flexural); 31,05±2,97 MPa (Tração Diametral); 135,6±24,8 KHN (Dureza Knoop); 5,6±0,95 GPa (Módulo de Elasticidade); 0,34±0,02 (Coeficiente de Poisson). Análises com ANOVA e Tukey demonstraram diferença estatística (p<0,05) para o teste de resistência à fratura: PFP (620,72±59,29)A, EXP-IND (506,54±27,07)B, EXP-DIR (157,76±32,34)C. O compósito experimental desenvolvido demonstrou propriedades mecânicas adequadas e viabilidade para à confecção de retentores intrarradiculares, entretanto dependente do método de confecção, sendo a confecção indireta o melhor método.

Avaliou-se, por meio do teste de microtração, a resistência adesiva da interface pino de fibras de vidro /cimento/ dentina radicular, variando-se cimentos, adesivos dentinários e tempo de armazenamento. Foram utilizados dentes caninos humanos permanentes, extraídos por razões periodontais, que tiveram suas coroas seccionadas e as raízes preparadas para receber pinos de fibras de vidro (Fibrekor). Os dentes foram aleatoriamente divididos em grupos de dez, variando a técnica de cimentação adesiva e o tempo de armazenamento. Os cimentos utilizados foram (1) Panavia F, (2) Variolink II, (3) Enforce, com seus respectivos adesivos. Avaliou-se também a influência da aplicação de uma camada do adesivo hidrofóbico Scotchbond Multi-Purpose Plus [SBMP] com o cimento Panavia F e Enforce. Espécimes cimentados com Variolink II, Panavia F com SBMP e Enforce com SBMP foram armazenados em água destilada por três meses. Após a cimentação, as raízes foram seccionadas (longitudinalmente e horizontalmente) com disco diamantado obtendo-se espécimes de 1mm de espessura, dois por terço da raiz. Os espécimes foram submetidos ao teste de microtração e o modo de fratura analisado em microscópio óptico. Os valores médios de resistência (MPa) foram submetidos aos testes ANOVA e Tukey (p < 0,05). A análise estatística mostrou (1) diferenças significativas na resistência adesiva entre cimentos e terços sendo que na média total dos terços, o cimento Variolink II foi superior aos outros cimentos; (2) na análise por terços, o cimento Variolink II mostrou valores estatisticamente superiores para o terço cervical. Os cimentos Panavia F e Enforce apresentaram valores significativamente menores no terço cervical; (3) diferenças significativas na resistência adesiva, com a aplicação do adesivo hidrofóbico, independente da região avaliada; (4) diminuição significativa na resistência adesiva para os cimentos Variolink II e Enforce, após armazenamento em água; (5) após o armazenamento, o cimento Variolink II apresentou diminuição na resistência adesiva no terço cervical e o cimento Enforce nos terços médio e apical. O cimento Panavia F exibiu aumento significativo da resistência adesiva nos terços cervical e médio, e diminuição no terço apical; (6) em microscopia óptica, um padrão de fraturas predominantemente do tipo adesiva para todos os experimentos. / This study evaluated the microtensile bond strengths of the fiber post-resin / resin cement/ root dentin when were varied the resin cement, dentin bonding system and longterm water storage. Were used for this study, human canines teeth extracted for periodontal reasons. The crown was sectioned and root canals were prepared for fiber post-resin (Fibrekor). The teeth were randomly assigned into experimental groups (n = 10) when were varied the resin luting technique and term water storage. The resin cements were (1) Panavia F, (2) Variolink II, (3) Enforce mediated by their respective adhesives. Experimental groups, using Panavia F and Enforce, were prepared in the same way, except that the additional layer of a low-viscosity bonding resin (Scotchbond Multi-Purpose Plus [SBMP]) was placed on the bonded root dentin surface before luting the fiber post-resin. The teeth were stored for 3 months and subsequently prepared for microtensile bond strength testing. Beams of approximately 1mm2 were tested in tension at 0,5mm/mim in a universal testing machine. Fractured surfaces were examined under X 40 stereomicroscope to determine the mode of fracture. The data were divided into cervical, middle and apical regions and analyzed using ANOVA and Tukey\'s test (p < 0,05). The results of tensile bonding strengths showed (1) significant differences among resin cements and root dentin regions, were presented higher mean bond strength values to Variolink II, when compared with others; (2) the cervical third of Variolink II demonstrated higher values, to Panavia F and Enforce demonstrated lower values for that regions; (3) the application of the additional layer of the hydrophobic adhesive resulted in significant improved in the tensile bonding strength; (4) water storage for 3 months produced bond strengths that were significant lower for Variolink II e Enforce; (5) after storage, the Variolink II reduced bond strengths in the cervical third and Enforce in the middle and apical regions. The cervical and middle third of Panavia F presented higher mean bond strength values and apical regions demonstrated lower values; (6) No cohesive fractures within resin cement, fiber-reinforced composite resin post, or root dentin were identified.