Academic literature on the topic 'Interface de-bonding'
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Journal articles on the topic "Interface de-bonding"
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Dai, Ying, Xing Ji, Lin Ye, and Yiu Wing Mai. "The Reliability of Fragmentation Test." Key Engineering Materials 312 (June 2006): 155–60. http://dx.doi.org/10.4028/www.scientific.net/kem.312.155.
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The single fiber fragmentation test has been continuously used to determine the interfacial shear strength. However, the results of the tests were still suspected by some researchers. To evaluate the reliability of the fragmentation test, the stress singularity near the interface end of fragmentation is investigated. According to the local failure modes near the interface end of a fiber fragment, there are three cases of the interface end conditions to be considered for the fragmentation tests: (A) fiber breaks only, without matrix cracking and de-bonding, (B) fiber breaks and matrix cracks, without interface de-bonding, (C) fiber breaks and interface de-bonds, with or without matrix cracking. After the singularity analysis of stress field near the interface end was depicted, it is obvious, that the interfacial shear strength given by the fragmentation test is not proper, because of that a stress singularity exists near the interface end.
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Wu, Ming Liang, Jian Kang Huang, Ri Hong Han, and Yu Shi. "Stress Simulation for DE-GMAW in Bonding Steel with Aluminum." Advanced Materials Research 268-270 (July 2011): 24–29. http://dx.doi.org/10.4028/www.scientific.net/amr.268-270.24.
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DE-GMAW (Double-Electrode Gas Metal Arc Welding) is a new welding technology. It is possible to change the melting current while the base metal current still be controlled at a desired level because the changed part of the melting current would be bypassed without flowing through the workpiece. So the heat input of base metal can be controlled accurately in DE-GMAW, and this welding method is suitable for dissimilar metal welding which has strict requirements for heat input of base metal, such as joining of steel and aluminum. On the basis of heat source model of DE-GMAW, numerical simulation and analysis on temperature field and residual stress for DE-GMAW in bonding steel and aluminum were done. The results show that residual stress after welding changed sharply from close 0 MPa to about 130 MPa at the interface of aluminum and steel. This value is greater than the binding force of steel, aluminum interface.
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Liu, Zhanke, Yin L. Young, and Michael R. Motley. "Transient Response of Partially-Bonded Sandwich Plates Subject to Underwater Explosions." Shock and Vibration 17, no. 3 (2010): 233–50. http://dx.doi.org/10.1155/2010/919304.
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This paper investigated the influence of interfacial bonding on the transient response of sandwich plates subject to underwater explosions. It was found that un-bonded sandwich plates receive lower impact energy, and are able to dissipate more energy through plastic deformation of the foam core, than perfectly bonded plates. Consequently, interfacial de-bonding leads to lower net energy transfer from the explosion to the target structure although it also increases the structural deformation due to stiffness reduction. Parametric studies showed that theadvantage(diminishing of net energy transfer) is more significant than thedisadvantage(magnification of the interface deflection). Thus, interfacial de-bonding through active/passive mechanisms may be beneficial for blast-resistant designs.
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Yang, Seung Yong. "Cohesive Zone Parameters for the Interface between NiTi Shape Memory Alloy and CFRP." Key Engineering Materials 321-323 (October 2006): 196–99. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.196.
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To explore the structural strength of CFRP shape memory alloy composites, it is necessary to evaluate the interface bonding strength. Jang and Kishi experimentally investigated the adhesive strength between NiTi fibers and CFRP composite [1]. In this paper, the interface de-decohesion behavior was simulated by three-dimensional cohesive zone method. The values of related numerical parameters were chosen to fit the experimental result.
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Du, Mao, Dongling Li, and Yufei Liu. "Investigation of Plasma Activated Si-Si Bonded Interface by Infrared Image Based on Combination of Spatial Domain and Morphology." Micromachines 10, no. 7 (July 2, 2019): 445. http://dx.doi.org/10.3390/mi10070445.
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This paper presents a detection method for characterizing the bonded interface of O2 plasma activated silicon wafer direct bonding. The images, obtained by infrared imaging system, were analyzed by the software based on spatial domain and morphology methods. The spatial domain processing methods, including median filtering and Laplace operator, were applied to achieve de-noising and contrast enhancement. With optimized parameters of sharpening operator patterns, disk size, binarization threshold, morphological parameter A and B, the void contours were clear and convenient for segmentation, and the bonding rate was accurately calculated. Furthermore, the void characteristics with different sizes and distributions were also analyzed, and the detailed statistics of the void’s number and size are given. Moreover, the orthogonal experiment was designed and analyzed, indicating that O2 flow has the greatest influence on the bonding rate in comparison with activated time and power. With the optimized process parameters of activated power of 150 W, O2 flow of 100 sccm and time of 120 s, the testing results show that the bonding rate can reach 94.51% and the bonding strength is 12.32 MPa.
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Vedovello, Silvia Amélia Scudeler, Marcelo Grigoletto, Mário Vedovello Filho, Heloísa Cristina Valdrighi, and Mayury Kuramae. "Knoop hardness of enamel and shear bond strength of brackets bonded with composite resin with and without fluoride." Dental Press Journal of Orthodontics 17, no. 4 (August 2012): e1-e5. http://dx.doi.org/10.1590/s2176-94512012000400007.
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OBJECTIVE: The aim of this study was to evaluate the Knoop hardness of enamel, shear bond strength and failure pattern (adhesive, bracket/resin interface or mixed) after bonding and debonding brackets, using resin composite with fluoride (Ortho Lite Cure, Ortho Source®) and without fluoride (Orthobond, Morelli®). METHODS: Fragments (6 mm x 6 mm) of 40 bovine incisor crowns were embedded in acrylic self-polymerizing resin. The Knoop hardness measurements were performed before and after bonding metal brackets. The specimens were divided into two groups, according to composite resin: with fluoride (Ortho Lite Cure, Ortho Source®) and without fluoride (Orthobond, Morelli®). After bonding, the specimens were submitted to demineralization and remineralization cycling for 14 days. Shear bond strength testing was performed in a universal test machine (EMIC), at 5 mm/min crosshead speed. RESULTS: There was no significant difference in shear bond strength between Groups I and II. After demineralization and remineralization procedures (DE/RE), the specimens bonded with Ortho Lite Cure showed higher Knoop hardness than Orthobond. For both groups there was predominance of failure at bracket/resin interface. CONCLUSION: specimens bonded with fluoride resin composite showed higher microhardness after DE/RE cycling than those bonded with resin composite without fluoride, although no difference in shear bond strength was found.
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Dai, Ying, Xing Ji, and Guo Dong Jiang. "Effect of Stress Singularity on Stress Distribution and Initial Debonding of Interface End." Key Engineering Materials 334-335 (March 2007): 641–44. http://dx.doi.org/10.4028/www.scientific.net/kem.334-335.641.
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Interfacial stress distribution of bonded quarter planes subjected a concentrated force was re-investigated based on Bogy’s solution [1]. It’s found that the characteristic length of the singularity of interface end (δ), varies with the index of stress singularity at interface end from millimeter to nanometer. This is a unique characteristic of stress singularity at interface end. How the characteristic length of the singularity of interface end (δ) influences the initial de-bonding of the interface end is a new question worth to pay attention. It’s found in the photoelasticity experiments that usually the debonding initiated at the interface end with singularity, but as the index of stress singularity, as well as the characteristic length of singularity of interface end, decrease to some extent, the initial debonding moves to an inner point near the interface end. This phenomenon clearly shows the index of stress singularity has obvious influence on the debonding of interface end.
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Lawrence, C. C., G. J. Lake, and A. G. Thomas. "New Technique for Measurement of Rubber-to-Metal Bond Failure." Rubber Chemistry and Technology 78, no. 2 (May 1, 2005): 271–85. http://dx.doi.org/10.5254/1.3547883.
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Abstract A new test, involving combined pure and simple shear, that can produce failure very close to the interface between the rubber and the bonding agent in a rubber-to-metal joint, is described. The test allows changes in the position of the tip of the de-bonded region to be followed with time, enabling the failure rate to be determined. The latter can be related to the strain energy release rate so that a fracture mechanics based analysis can be applied. Failure characteristics can be correlated with features of the de-bond surface. The results suggest that even when failure is very close to the interface, the measured strength is similar to that of the rubber.
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Neto, Julio Pedra e. Cal, José de Albuquerque Calasans-Maia, Natalia Valli de Almeida, Helen Rohen, and Maria Angélica Galvão Freire. "Effect of a Metal Primer on the Adhesive Interface between Composite and Lingual Brackets." Journal of Contemporary Dental Practice 14, no. 6 (2013): 1106–8. http://dx.doi.org/10.5005/jp-journals-10024-1459.
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ABSTRACT Aim To test the null hypothesis was that there is no difference in the shear strength of indirectly bonded lingual brackets with or without prior application of metal primer on their bases. Materials and methods Forty recently extracted human premolars were obtained and randomly divided into two groups of 20 each: group I (control), phosphoric acid and indirect bonding with Maximum Cure (Reliance Orthodontic Products, Itasca, IL, USA); and group II, application of metal primer (Metal Primer, Reliance Orthodontic Products) on bracket base prior to conditioning and indirect bonding. All products were used according to the manufacturer's instructions. A universal testing machine was used to apply a shear force directly onto the enamel- bracket interface at a speed of 1.0 mm/min. Results Mean (SD) shear bond strength for group I was 12.87 (5.75) MPa and for the group II was 18.47 (8.48) MPa. The Student's t-test showed a significant difference (p = 0.0311) between the groups. The chi-square test for the adhesive remnant index (ARI) indicated that there was a significant difference (p = 0.2750). Conclusion The application of metal primer increased the adhesion of lingual brackets, and may be a promising procedure for clinical orthodontics. How to cite this article e Cal Neto JP, de Albuquerque Calasans-Maia J, de Almeida NV, Rohen H, Freire MAG. Effect of a Metal Primer on the Adhesive Interface Between Composite and Lingual Brackets. J Contemp Dent Pract 2013;14(6):1106- 1108.
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Filho, E. J. A., P. R. P. Motoyama, J. S. Mendonça, J. C. Silva, and T. A. D. Mendes. "A Eficácia Clínica da Técnica Úmida Etanólica em Restaurações de Resina Composta: Revisão de Literatura." Journal of Health Sciences 19, no. 5 (February 23, 2018): 95. http://dx.doi.org/10.17921/2447-8938.2017v19n5p95.
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O objetivo do presente estudo foi revisar a literatura a cerca da eficácia clínica na técnica úmida etanólica (TUE) em restaurações com resinas compostas. Foi realizada uma busca nas bases de dados PubMed, Bireme e Cochrane Library de artigos em inglês do período de 2007 a 2017, utilizando os seguintes descritores: Dentin, Dentin-Bonding Agents e Ethanol como estratégia de busca. Foram encontrados 101 artigos, dos quais apenas os ensaios clínicos foram selecionados, totalizando 6, mediante a relevância, sendo os demais artigos excluídos do presente estudo. A TUE consiste na substituição de água livre em dentina por solvente livre de água, etanol absoluto. A técnica simplificada consiste na aplicação de etanol absoluto por 1 minuto, previamente a aplicação do “Bond”, de adesivo convencional de 3 passos. A TUE tem se mostrado bastante promissora, pois vai haver a remoção de água presente na dentina, através de desidratação química e um encolhimento das fibras colágenas permitindo que os monômeros hidrofóbicos penetrem mais facilmente em dentina, sem o uso de “primers”. Dessa forma, diminuirá a sorção dos monômeros, consequentemente a hidrólise e a degradação da interface de união restauração/adesivo, aumentando a longevidade da restauração. Entretanto quando se trata de estudos clínicos a sua eficácia ainda não é bem estabelecida, acredita-se que seja por ação da pressão pulpar. Dessa forma, são necessários mais estudos clínicos e um maior período de observação para avaliar a durabilidade clínicas de restaurações com essa técnica.Palavras-chave: Dentin. Dentin-Bonding. Agents. Ethanol.
Dissertations / Theses on the topic "Interface de-bonding"
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Dekious, Ali. "Etude de la réponse acoustique des collages directs et temporaires." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT319.
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Le collage direct est maintenant utilisé par un nombre croissant d'applications en microélectronique (Elaboration de SOI, technologie imager Back Side Illumination, technologies 3D...). C'est une technique d'assemblage permettant de coller deux surfaces sans apport de matière adhésive. Principalement utilisée pour le collage de wafers, elle vient en complément de techniques telles que l'épitaxie ou le dépôt de couches minces. Ce collage s'effectue sous certaines conditions : il faut que les surfaces soient suffisamment propres, planes et lisses pour qu'il y ait une adhésion spontanée à température et pression ambiante. Enfin, un traitement thermique est appliqué pour augmenter l'énergie d'adhérence. Pendant le processus de fabrication, il peut apparaître des défauts de collage qui sont essentiellement dus à un piégeage de particules. Ces défauts se présentent sous la forme de bulles d'air. Finalement, les défauts de collage et l'énergie de collage sont les deux caractéristiques à partir desquelles est déduite une qualité de collage.Aujourd'hui, la technique utilisée pour la mesure d'énergie de collage est le clivage au coin. C'est une technique qui consiste dans un premier temps à séparer partiellement deux wafers par une lame, et dans un second temps, à calculer l'énergie de collage à partir d'une équation comportementale qui intègre la longueur de décollement. Mis à part le fait qu'elle permette la mesure d'énergie seulement sur quelques points, il se trouve que c'est une technique destructive. Un contrôle non destructif serait très intéressant pour l'industrie microélectronique et spécialement pour les lignes d'inspection. De plus, les procédés de fabrication microélectronique n'étant pas uniforme, avoir la possibilité d'obtenir une cartographie d'énergie de collage serait un atout majeur. A ce jour, aucune technique respectant ces deux exigences n'est connue. L'objectif de cette étude est d'utiliser la microscopie acoustique pour mesurer l'énergie de collage.Dans cette étude, un modèle inspiré de la "méthode des matrices hybrides" a été développé afin de modéliser des collages de différentes qualités. Le résultat de la modélisation montrera que le coefficient de réflexion acoustique de la structure collée est influencé par la qualité d'interface. En se plaçant dans des conditions précises, une méthode expérimentale est alors réalisée pour la mesure de la qualité d'interface. En parallèle, des wafers de Silicium réalisés par collage direct ont été spécialement conçus pour valider la méthode. Sur ce principe, des cartographies bidimensionnelles d'énergie de collage sont réalisées.Dans un second temps, la technique est améliorée afin d'augmenter la résolution latérale. Pour cela, un transducteur ayant une lentille est utilisé pour focalisé les ondes ultrasonores en points du collage. Une étude théorique est tout d'abord menée en utilisant le modèle du "spectre angulaire" afin de simuler la diffraction par la lentille. Enfin, des cartographies expérimentales confirmeront la faisabilité de mesures d'énergie de collage hautes résolutionsDirect bonding is used for many applications in microelectronics (SOI Silicon-On-Insulator technology, imager back side illumination technology, 3D technology...). It is a processes that consists in an assembly of two surfaces without any adhesive material. It is primarily used to bond silicon wafers and it is complementary with other microelectronics technique such as epitaxy, thin film deposition... Bonding requires special wafer surface conditions and preparations. The surfaces have to be clean, flat and smooth to obtain a spontaneous adhesion at ambient temperature and atmospheric pressure. A heat treatment is applied to increase the adherence energy. During the manufacturing process, bonding defects may appear which are due to trapping of particles. These bonding defects are essentially formed of air. Finally, bonding defects and bonding energy are the two main characteristics from which is deduced the bonding quality.Nowadays, the main technique that is used to measure the direct bonding energy is the double cantilever beam (DCB). The method consists in firstly partially separating the two wafers by a blade, and secondly calculating the bonding energy from an equation that integrates the debonding lenght. The major disadvantage of this technique is its destructiveness. Furthermore it is only possible to make measurements on few points.Thus a non-destructive characterisation could be very interesting especially for an industrial in-line inspection. Moreover, having the possibility to obtain a mapping of the bonding energy could lead to interesting development. Up to know, no technique can reach the both requirements. The aim of this work is to use the acoustic microscopy to measure the direct bonding energy.In this study, a model based on "hybrid matrix method" has been developed to model bonding with different qualities. The results of the modelling show that the acoustic reflection coefficient of the bonded structure is influenced by the quality of the interface. From these results, an experimental method is proposed to perform quality of the interface measurements from the reflection coefficients acquired under normal incidence. In parallel, silicon wafers have been bonded to validate the method. Finally, once the method validated, two-dimensional mappings of the interface quality are realised.Secondly, the technique is improved to increase the lateral resolution. For this, a transducer having a lens is used to focus the ultrasonic waves on the bonded structure. A theoretical study is conducted using the model of the "angular spectrum" to simulate the diffraction lens. Finally, experimental mapping confirm the feasibility of measuring bonding energy of high resolutions
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Martin, Júnior Manoel. "Sistemas adesivos convencional e autocondicionante : análise micromecânica tridimensional da interface dentina-adesivo /." Araçatuba : [s.n.], 2008. http://hdl.handle.net/11449/105580.
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Orientador: Eduardo Passos RochaBanca: Marco Antonio Luersen
Banca: Renato Herman Sundfeld
Banca: Marcelo Giannini
Banca: Washington Rodrigues Camargo
Resumo: OBJETIVO: Avaliar a distribuição das tensões na interface dentina-adesivo variando o sistema adesivo, convencional e autocondicionante, através do método dos elementos finitos tridimensional. MATERIAL E MÉTODO: Foram elaborados 4 modelos no programa Solidworks 2007, sendo: Mc - representação de um espécime em dentina (41x41x82 μm) restaurado com resina composta (RC), apresentando camada de adesivo, camada híbrida (CH), TAGs, dentina peri-tubular, dentina intertubular parcialmente desmineralizada, dentina intertubular e prolongamento odontoblástico, simulando a formação da CH segundo o sistema adesivo convencional; Mr - idêntico ao Mc, com ramificações laterais do infiltrado do adesivo; Ma - idêntico ao Mc, sem TAGs, e com "smear plug", simulando o sistema adesivo autocondicionante; Mat - idêntico ao Ma, com TAGs. Os modelos foram considerados isotrópicos, homogêneos e linearmente elásticos e a análise numérica foi realizada no ANSYS Workbench 10.0 para obtenção da máxima tensão principal (MAX) após aplicação de força de tração de 0,03 N perpendicular à superfície da RC. A base de todos os modelos foi fixada nos eixos x, y e z. RESULTADOS: A MAX foi maior para o sistema convencional. A presença da ramificação lateral aumentou a MAX na CH para o sistema convencional. Os TAGs modificaram a distribuição da MAX na camada de adesivo para o sistema autocondicionante. CONCLUSÃO: A CH para o sistema convencional apresentou maior MAX em comparação ao sistema autocondicionante. A presença das ramificações laterais do adesivo aumentaram a tensão na CH para o sistema convencional.
Abstract: OBJECTIVE: The aim of this study was to evaluate the stress distribution in the hybrid layer varying the adhesive system (total each and self-etching systems) using three-dimensional finite element analysis (FE). METHODS: 4 FE models (M) were developed in Solidworks 2007: Mc - representation of a specimen of dentin (41x41x82 μm) restored with composite resin (RC), showing the adhesive layer, hybrid layer (HL), TAGs, peri-tubular dentin, intertubular dentin in order to simulate simulating the HL according to the total-etch adhesive system; Mr - similar to Mc, with lateral branches of the adhesive; Ma - similar to Mc, without TAGs and showing the "smear plug" in order to simulate the environment for the self-ethcing adhesive system; Mat - similar to Ma, with TAGs. The models were considered isotropic, homogeneous and linearly elastic and numerical analysis was performed in ANSYS Workbench 10.0 to obtain the maximum principal stress (MAX) after application of a tension force of 0.03N perpendicular to the surface of the RC. The botton of all models was fixed in x, y and z axis. RESULTS: The highest MAX in HL was observed in the total etching system. The lateral branches increased the MAX in HL. The TAGs had a little influence on the stress distribution in self-ethching system. CONCLUSION: The HL for the total-etch system showed MAX higher in comparison with the self-etch system. The presence of TAGs increased the MAX in the HL for the total-etch system.
Doutor
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Anchieta, Rodolfo Bruniera. "Sistemas adesivos autocondicionantes : estudo micromecânico da interface de união através do método dos elementos finitos tridimensional /." Araçatuba : [s.n.], 2010. http://hdl.handle.net/11449/97368.
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Resumo: Introdução: Embora os sistemas adesivos autocondicionantes se caracterizem por desmineralizar e infiltrar a dentina simultaneamente, a presença de dentina alterada abaixo da camada híbrida tem sido reportada, sugerindo comportamento mecânico distinto. Proposição: Avaliar por meio do método dos elementos finitos tridimensional a influência da espessura da dentina parcialmente alterada no comportamento micromecânico de dois sistemas adesivos autocondicionantes. Materiais e Métodos: Foram elaborados 5 micro-modelos (M) simulando a interface dentina/adesivo (d/a) (82x41x41 μm), sendo: M1-representação da interface d/a baseada em sistema adesivo convencional de 2 passos; M2-representação de um sistema adesivo autocondicionante de 2 passos. Nos M3, M4 e M5 representação de um sistema adesivo autocondicionante de 1 passo, variando a espessura da camada de dentina parcialmente alterada em 0, 1,5 e 3 μm, respectivamente. Os modelos foram considerados isotrópicos, homogêneos e linearmente elásticos. A base de todos os modelos foi fixada nos eixos x, y e z, sendo aplicado um carregamento em tração (90º; 0,03 N) na face superior da resina composta. A análise numérica foi realizada para a obtenção da tensão principal máxima ( max). Resultados: o pico da max (MPa) foi encontrada no M5 (79,5), seguido do M4 (78,0) e do M3 (70). O topo dos tags foi o local mais solicitado em todos os modelos. Conclusão: O aumento da espessura da dentina parcialmente alterada aumentou a tensão na interface d/a; a ausência desta camada contribuiu para a menor concentração de tensão; o topo dos tags foi o local mais exigido na interface d/a.Abstract: Introduction: Although the self-etching adhesives are characterized by etching and infiltrating simultaneously the dentin, the presence of an altered dentin layer has been showed by literature, which might show specific mechanical behavior. Proposition: To evaluate through 3-D finite element analysis the influence of the partially altered dentin thickness on the micromechanical behavior of the self-etch adhesives. Materials and Methods: 5 micro-models (M) were developed for simulating the dentin/adhesive (d/a) interface (82x41x41 μm): M1-representation of the d/a interface based on 2 steps conventional adhesive system; M2-d/a interface based on 2 steps self-etch adhesive system M3, M4 and M5 - d/a interface based on all-in-one adhesive system, varying the thickness of the partially altered dentin (0, 1.5 and 3 μm, respectively). All the models were considered isotropic, homogeneous and lineally elastic. The bottom of all the models were constrained in the axes x, y and z. A tensile load (90o; 0.03N) was applied on the top of the composite resin. The numeric analysis was accomplished, being obtained the maximum principal stress ( max). Results: The pick of max (MPa) was found in M5 (79.5), followed by M4 (78.0) and M3 (70). The top of the resin tags was the most requested place in all models. Conclusion: The increase of the partially altered dentin thickness raised the max in the d/a interface; the absence of this layer contributed to the smallest tension concentration; the top of the tags showed higher stress concentration.
Orientador: Eduardo Passos Rocha
Coorientador: Renato Herman Sundfeld
Banca: Paulo Henrique dos Santos
Banca: André Figueiredo Reis
Mestre
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Sánchez-ayala, Alfonso. "AVALIAÇÃO DA INFLUÊNCIA DA CICLAGEM TÉRMICA E MECÂNICA NA EFETIVIDADE DA INTERFACE ADESIVA." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2008. http://tede2.uepg.br/jspui/handle/prefix/1695.
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Previous issue date: 2008-01-31The aim of this study was to evaluate in vitro the adhesive effectiveness in class V cavities using four different adhesive systems, being submit to thermocycling and occlusal load cycling. The cavities had a dimension of 3x2x1.8 mm3 and were made on amelo-cement junction on buccal and lingual of 80 human premolars (n=160). The used adhesive systems were Adper Single Bond 2, AdheSE, Adper Prompt LPop and One Coat 7.0. The used composite was Synergy® D6. The adhesive and photopolymerization (600 mW/cm2) proceedings were made conventionally and following the manufacturer recommendations. The specimens were divided in 4 groups (n=40) according to adhesive system used. Each group was divided in 4 subgroups (n=10) according to applycated stress (thermocycling, occlusal load cycling and thermocycling+occlusal load cycling). Each subgroup included 1 control group without stressing. The thermocycling was made using 500 cycles, with 5-55 C, dwell time of 15 seg and transfer time of 5 seg. The occlusal load cycling was made applying a force of 40-70 N during 50000 cycles with 2 Hz of frequency. Later, the specimens were impermeabilited and immersed in tracer agent of 50 % silver nitrate solution by 2 hours. Finally, the specimens were prepared for adhesive effectiveness evaluation through optic microscopy 40X (marginal microleakage occurrence) and scanning electronic microscopy 1000X (gaps formation). The tracer agent microleakage was measured qualitative (score) and quantitatively . The gap width was measured on 3 points of center of axial wall. The Kruskal-Wallis and post-hoc de Dunn, and ANOVA two-way and post-hoc Bonferroni tests were used on statistic analysis. Despite of few differences found in used adhesive system performance, the tendency could be observed to the increase of the marginal microleakage in the submitted groups specifically to thermocycling. On the other hand, the axial gaps formation presented progressively higher width in the submitted groups to thermocycling, occlusal load cycling and thermocycling+occlusal load cycling. It was concluded that the used adhesive system presented similar adhesive effectiveness when were submitted to thermal and mechanical stress.
A proposição deste estudo foi avaliar in vitro a efetividade adesiva em cavidades de classe V utilizando quatro diferentes sistemas adesivos, sendo submetidas a termociclagem e carga cíclica oclusal. As cavidades tiveram uma dimensão de 3x2x1.8 mm3 e foram realizadas na união amelo-cementária em vestibular e lingual de 80 pré-molares humanos (n=160). Os sistemas adesivos empregados foram Adper Single Bond 2, AdheSE, Adper Prompt L-Pop e One Coat 7.0. A resina composta utilizada foi Synergy D6. Os procedimentos de adesão e fotopolomerização (600 mW/cm2) foram realizados convencionalmente e seguindo as recomendações do fabricante. Os espécimes foram divididos em 4 grupos (n=40) segundo o tipo sistema adesivo utilizado. Cada grupo foi dividido em 4 subgrupos (n=10) segundo o tipo de estresse aplicado (termociclagem, carga cíclica oclusal e termociclagem+carga cíclica oclusal). Cada subgrupo incluiu 1 grupo controle sem estresse. A termociclagem foi realizada utilizando 500 ciclos a 5-55 C, 15 seg de tempo de permanência em cada temperatura e 5 seg de tempo de transferência. A carga cíclica oclusal foi realizada aplicando uma força de 40-70 N durante 50000 ciclos com freqüência de 2 Hz. Posteriormente, os espécimes foram impermeabilizados e imersos em agente traçador de solução a 50 de nitrato de prata por 2 horas. Finalmente, os espécimes foram preparados para a avaliação da efetividade adesiva por meio de microscopia óptica 40X (ocorrência de microinfiltração marginal) e microscopia eletrônica de varredura 1000x (formação de fendas). A microinfiltração do agente traçador foi mensurada qualitativa (escore) e quantitativamente . A largura das fendas foi medida (μm) em 3 pontos do centro da parede axial. Os testes de Kruskal-Wallis e post-hoc de Dunn, e ANOVA two-way e post-hoc Bonferroni foram utilizados na análise estatística. Apesar das poucas diferenças significativas encontradas no desempenho dos sistemas adesivos utilizados, pôde-se observar a tendência ao aumento da microinfiltração marginal nos grupos submetidos especificamente a termociclagem. Por outro lado, a formação de fendas axiais apresentaram progressivamente maior largura nos grupos submetidos a termociclagem, carga cíclica e termociclagem+carga cíclica. Concluise que os sistemas adesivos avaliados apresentaram efetividade adesiva similar quando foram submetidos a estresse térmico e mecânico.
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Arrais, Cesar Augusto Galvão. "Influencia dos modos de ativação no grau de conversão, resitencia e morfologia da interface de união de sistemas de cimentação e adesivos." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/287822.
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Orientador: Marcelo GianniniTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ondontologia de Piracicaba
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Resumo: A não fotoativação do sistema adesivo previamente à aplicação do cimento resinoso tem sido proposta quando sistemas de cimentação de dupla ativação (SCDA - sistemas adesivos de dupla ativação / cimentos resinosos de dupla ativação) são utilizados. Entretanto, existe uma carência de relatos científicos a respeito da efetividade dos SCDA. Os objetivos deste estudo foram: 1- avaliar a resistência de união (RU) e a morfologia da interface de união de restaurações indiretas de compósito através da utilização da microscopia confocal laser quando os sistemas adesivos de dupla ativação foram ou não fotoativados previamente à aplicação dos cimentos resinosos; 2- analisar o grau de conversão (GC), através da Espectroscopia Infravermelha Transformada de Fourier (FTIR), e a RU de SCDAs quando a fotoativação não foi realizada ou atenuada pela presença da restauração indireta; 3- avaliar o GC e resistência coesiva de sistemas de união quando utilizados diferentes unidades de fotoativação (LEDs e de luz halógena). A RU e resistência coesiva foram avaliadas através do ensaio de microtração. Para a análise em microscopia confocal laser, diferentes corantes foram incorporados nos SCDAs previamente à sua aplicação. Para a análise do GC, os SCDAs foram aplicados na superfície do diamante da unidade de reflectância total atenuada acoplada ao espectrômetro infravermelho. O GC dos sistemas de união não relacionados aos SCDAs foi obtido utilizando-se filmes de resina adesiva. Os resultados demonstraram que a não fotoativação do sistema adesivo de dupla ativação previamente à cimentação não afetou a RU, e que os valores foram até superiores para um SCDA de 4ª geração quando o agente de união não foi fotoativado. A análise em microscopia confocal laser exibiu variação nas características morfológicas da interface de união, variando de acordo com o SCDA utilizado e com o modo de ativação de ambos componentes (sistema adesivo e cimento resinoso). Para alguns SCDAs, o GC foi reduzido pela presença do disco de compósito posicionado entre o SCDA e a ponta da unidade fotoativadora. A não fotoativação dos SCDAs resultou em GC inferiores aos obtidos com exposição direta da luz. A não fotoativação da maioria dos SCDAs também resultou em valores inferiores de RU, exceto quando um sistema de 4ª geração foi utilizado. A utilização de LED resultou em GC inferior ao obtido quando a luz halógena foi utilizada mas não afetou a resistência coesiva dos sistemas adesivos avaliados. Pode-se concluir que a não fotoativação dos sistemas adesivos é uma alternativa aceitável durante a cimentação de restaurações indiretas, porém os SCDAs necessitam de luz fotoativadora para garantir adequada RU. A utilização de LEDs pode comprometer o GC dos sistemas adesivos
Abstract: The lack of light-activation of dual-cured bonding agents before the resin cement application has been an alternative technique of cementing indirect restorations when dual-cured cementing systems are used (DCS ¿ dual-cured bonding agents / dual-cured resin cements). However, few reports exist regarding the effectiveness of DCS when dual-cured bonding agents are left in the uncured state before the seating of the indirect restoration. Therefore, the aims of this study were: 1- to evaluate the microtensile bond strength (MTBS) and micromorphology of the adhesive interface of indirect restorations by confocal laser microscopy (CLSM) when the dual-cured bonding agents were left in the uncured state; 2- to analyze the degree of conversion (DC) by Fourier Transformed Infrared Spectroscopy and the bond strength of indirect restorations when DCSs were applied to the tooth and light activated or allowed to self-cure; 3- to evaluate the DC and ultimate tensile strength (UTS) of bonding agents light-activated with light curing units (LEDs and halogen light). The MTBS and UTS were analyzed using microtensile bond strength test. Different dyes were incorporated to the DCSs before they were applied to teeth for the CSLM analysis. For the DC analysis, the DSCs were applied to the diamond surface of attenuated total reflectance unit of the infrared device. The DC of the bonding agents related to the study evaluating the effectiveness of light-curing units was obtained from thin resin adhesive films. The results demonstrated that the MTBS was not affected, and the values were even higher for one 4th generation DCS, when the dual-bonding agents were left in the uncured state before the resin cement application. The CLSM analysis exhibited some variation in the micromorphological features, which depended on the DCSs and on the curing modes of bonding agents and resin cements. Some DCSs showed lower DC when pre-cured resin composite discs were used. The self-cured groups exhibited lower MTBS than the light-activated ones, except for one 4th generation DCS. The LED promoted lower DC in all bonding agents than did the halogen light. No difference in UTS was observed when LED was used. It was concluded that leaving the dual-cured bonding agent in the uncured state before seating the indirect restoration may be a reliable technique to ensure adequate MTBS, but most DCSs should be light-activated after seating the indirect restoration to provide optimal bond strength. Some LEDs can compromise the DC of adhesive systems
Doutorado
Dentística
Doutor em Clínica Odontológica
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Peliz, Fernandes Maria Inez Lemos [UNESP]. "Avaliação da interface dentina/agentes protetores em restaurações com resina composta, através de microscopia eletrônica de varredura." Universidade Estadual Paulista (UNESP), 2003. http://hdl.handle.net/11449/101401.
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pelizfernandes_mil_dr_arafo.pdf: 974117 bytes, checksum: ac5bfc8ea4cf08f87cfa61b609255346 (MD5)O objetivo deste estudo foi avaliar a formação de microfendas entre diferentes agentes de proteção do complexo dentina-polpa e a estrutura dental. Cavidades de classe V, com dimensões padronizadas, foram preparadas nas faces V e L de 60 terceiros molares humanos recém-extraídos, divididos em 6 grupos: (1) Single Bond-SB, 3M ESPE; (2) Life-LF, Kerr Co.+ SB; (3) LF+Vitrebond-VT, 3M ESPE +SB; (4) VT+SB; (5) SB+VT; (6) SB+VT+SB; e restauradas com resina composta microhíbrida Filtek Z250 (3M ESPE), segundo as normas estabelecidas pelos fabricantes, exceto para os grupos 5 e 6 onde a dentina foi hibridizada previamente à aplicação do ionômero de vidro modificado por resina. Após ciclagem térmica, um segmento longitudinal de 800 æm de espessura foi obtido da porção central de cada restauração e, em seguida, submetidos às etapas de fixação, desidratação em grau ascendente de etanol e secagem através de HMDS. A adaptação interna dos materiais à parede axial foi analisada através do MEV, com 1000x de magnificação. Os dados obtidos foram analisados através do procedimento estatístico não-paramétrico de Kruskal-Wallis (p<0.05). O cimento de hidróxido de cálcio e ionômero de vidro modificado por resina aplicados sozinhos ou em conjunto (p<0.001), sob restauração de resina composta, resultou em microfendas com amplitude estatisticamente maiores do que quando a dentina foi somente hibridizada previamente a restauração. A hibridização dentinária permitiu selamento superior da interface dentina/restauração do que os demais agentes protetores avaliados.
The objective of this study was to evaluate the microgap with different materials used for pulp protection. The null hypothesis tested in this in vitro study was that the combination among calcium hydroxide, resin-modified glass ionomer and dentin adhesive, used as pulp protection in composite restorations would not result in greater axial gap than that obtained by hybridization only. Standardized class V preparations were performed in buccal and lingual surfaces of sixty caries-free extracted human third molars. The prepared teeth were randomly assessed in 6 groups: (1) Single Bond-SB, 3M ESPE; (2) Life-LF, Kerr Co.+ SB; (3) LF+Vitrebond-VT, 3M ESPE +SB; (4) VT+SB; (5) SB+VT; (6) SB+VT+SB; and restored with a microhybrid composite resin Filtek Z250 (3M ESPE), following the manufacturer's instructions. Except for group 5 and 6, which the ethanol- and water-based adhesive were applied prior the resin-modified glass ionomer. The specimens were then cross-sectioned with a thickness of 800 æm, fixed, dehydrated in ascending ethanol, and dried by means HMDS. The specimens were mounted in stubs, sputter coated and the internal adaptation of the materials to the axial wall analyzed under SEM with 1,000x magnification. The data obtained were analyzed with nonparametric tests (Kruskal-Wallis, p<0.05). The null hypothesis was rejected. Calcium hydroxide and resin-modified glass ionomer applied alone or in conjunction (p<0.001), under composite resin restoration, resulted in statistically wider micro gaps than when the dentin was only hybridized prior the restoration. Dentin hybridization provides superior sealing of the dentin and restoration interface than other pulp protection materials.
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Peliz, Fernandes Maria Inez Lemos. "Avaliação da interface dentina/agentes protetores em restaurações com resina composta, através de microscopia eletrônica de varredura /." Araraquara : [s.n.], 2003. http://hdl.handle.net/11449/101401.
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Orientador: Sillas Luiz Lordelo Duarte JúniorBanca: Welingtom Dinelli
Banca: Marcelo Ferrarezi de Andrade
Banca: José Roberto Cury Saad
Banca: Manio de Carvalho Tibúrcio
Banca: Camilo Anauate Netto
Resumo: O objetivo deste estudo foi avaliar a formação de microfendas entre diferentes agentes de proteção do complexo dentina-polpa e a estrutura dental. Cavidades de classe V, com dimensões padronizadas, foram preparadas nas faces V e L de 60 terceiros molares humanos recém-extraídos, divididos em 6 grupos: (1) Single Bond-SB, 3M ESPE; (2) Life-LF, Kerr Co.+ SB; (3) LF+Vitrebond-VT, 3M ESPE +SB; (4) VT+SB; (5) SB+VT; (6) SB+VT+SB; e restauradas com resina composta microhíbrida Filtek Z250 (3M ESPE), segundo as normas estabelecidas pelos fabricantes, exceto para os grupos 5 e 6 onde a dentina foi hibridizada previamente à aplicação do ionômero de vidro modificado por resina. Após ciclagem térmica, um segmento longitudinal de 800 æm de espessura foi obtido da porção central de cada restauração e, em seguida, submetidos às etapas de fixação, desidratação em grau ascendente de etanol e secagem através de HMDS. A adaptação interna dos materiais à parede axial foi analisada através do MEV, com 1000x de magnificação. Os dados obtidos foram analisados através do procedimento estatístico não-paramétrico de Kruskal-Wallis (p<0.05). O cimento de hidróxido de cálcio e ionômero de vidro modificado por resina aplicados sozinhos ou em conjunto (p<0.001), sob restauração de resina composta, resultou em microfendas com amplitude estatisticamente maiores do que quando a dentina foi somente hibridizada previamente a restauração. A hibridização dentinária permitiu selamento superior da interface dentina/restauração do que os demais agentes protetores avaliados.
Abstract: The objective of this study was to evaluate the microgap with different materials used for pulp protection. The null hypothesis tested in this in vitro study was that the combination among calcium hydroxide, resin-modified glass ionomer and dentin adhesive, used as pulp protection in composite restorations would not result in greater axial gap than that obtained by hybridization only. Standardized class V preparations were performed in buccal and lingual surfaces of sixty caries-free extracted human third molars. The prepared teeth were randomly assessed in 6 groups: (1) Single Bond-SB, 3M ESPE; (2) Life-LF, Kerr Co.+ SB; (3) LF+Vitrebond-VT, 3M ESPE +SB; (4) VT+SB; (5) SB+VT; (6) SB+VT+SB; and restored with a microhybrid composite resin Filtek Z250 (3M ESPE), following the manufacturer's instructions. Except for group 5 and 6, which the ethanol- and water-based adhesive were applied prior the resin-modified glass ionomer. The specimens were then cross-sectioned with a thickness of 800 æm, fixed, dehydrated in ascending ethanol, and dried by means HMDS. The specimens were mounted in stubs, sputter coated and the internal adaptation of the materials to the axial wall analyzed under SEM with 1,000x magnification. The data obtained were analyzed with nonparametric tests (Kruskal-Wallis, p<0.05). The null hypothesis was rejected. Calcium hydroxide and resin-modified glass ionomer applied alone or in conjunction (p<0.001), under composite resin restoration, resulted in statistically wider micro gaps than when the dentin was only hybridized prior the restoration. Dentin hybridization provides superior sealing of the dentin and restoration interface than other pulp protection materials.
Doutor
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Neto, Aminthas Alves Brasil. "AvaliaÃÃo da resistÃncia de uniÃo da interface adesiva de pinos de fibra de vidro e a dentina radicular." Universidade Federal do CearÃ, 2007. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=668.
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nÃo hÃO objetivo deste trabalho foi avaliar a resistÃncia de uniÃo da interface adesiva de pinos de fibra de vidro e dentina radicular, em trÃs regiÃes do conduto, fixados com trÃs sistemas de cimentaÃÃo. Vinte e quatro dentes humanos hÃgidos, recÃm-extraÃdos por razÃes ortodÃnticas ou periodontais, tiveram suas coroas removidas na junÃÃo cemento-esmalte com um disco diamantado, sob irrigaÃÃo. As raÃzes receberam tratamento endodÃntico e foram obturadas com guta-percha e um cimento endodÃntico contendo eugenol (Endofil). A desobstruÃÃo foi realizada uma semana apÃs o tÃrmino do tratamento endodÃntico em uma profundidade de 9 mm medida da regiÃo cervical da raiz. O pino (Reforpost Fibra de Vidro n 3) foi cimentado no conduto radicular com um dos trÃs sistemas de fixaÃÃo descritos a seguir (n = 8): no grupo 1 foi utilizado o sistema Single Bond 2/ RelyX ARC, no grupo 2 foi utilizado o sistema ED Primer/Panavia 21 e no grupo 3 foi utilizado o cimento RelyX Unicem. Todos os cimentos e sistemas adesivos foram utilizados de acordo com as instruÃÃes dos fabricantes. Posteriormente, as raÃzes foram seccionadas em uma mÃquina de corte, sob irrigaÃÃo, em trÃs porÃÃes, correspondentes aos terÃos cervical, mÃdio e apical da regiÃo do conduto preparada para o pino. Os espÃcimes foram submetidos ao teste de extrusÃo por cisalhamento (âpush-outâ) em uma mÃquina de ensaio universal a uma velocidade de 0,5 mm/min e os valores de resistÃncia de uniÃo mÃxima foram registrados e submetidos à anÃlise estatÃstica (p < 0,05). A anÃlise de variÃncia (ANOVA) mostrou diferenÃa estatÃstica significante entre os terÃos (cervical, mÃdio e apical) somente para o grupo do cimento Panavia 21, no qual o terÃo apical apresentou menor mÃdia de resistÃncia de uniÃo do que os terÃos cervical e mÃdio (teste de Tukey). Quando se comparou a resistÃncia de uniÃo em cada regiÃo da raiz, avaliando-se os materiais de cimentaÃÃo, a anÃlise de variÃncia (ANOVA) mostrou diferenÃa estatÃstica significante para as trÃs regiÃes do conduto. Para os terÃos mÃdio e apical, o cimento Panavia 21 apresentou mÃdia de resistÃncia de uniÃo significativamente menor do que os cimentos Single Bond 2/RelyX ARC e RelyX Unicem, sendo estes estatisticamente iguais entre si. Para o terÃo cervical, o cimento RelyX Unicem apresentou maiores valores de resistÃncia de uniÃo do que o cimento Panavia 21, tendo sido o cimento Single Bond 2/RelyX ARC estatisticamente semelhante aos outros dois materiais
The aim of this study was to assess the bond strength at the adhesive interface of fiber glass posts and root dentin, in three regions of the canal, fixed with three cementation systems. Twenty-four healthy human teeth, recently extracted for orthodontic or periodontal reasons, had their crowns removed at the cement-enamel junction with a diamond disk, under irrigation. The roots were endodontically treated and were filled with gutta percha and an endodontic cement containing eugenol (Endofil). One week after endodontic treatment ended, the obstruction was removed at a mean depth of 9mm in the cervical region of the root. The posts (Reforpost Fibra de Vidro No. 3) were cemented in the canals prepared with one of the three fixation systems described as follows (n = 8): in group 1 the Single Bond 2/ RelyX ARC system was used; in group 2 the ED Primer/Panavia 21 system, and in group 3 RelyX Unicem cement was used. All the cements and adhesive systems were used in accordance with the manufacturersâ instructions. Afterwards, the roots were sectioned in a cutting machine under irrigation, into three portions corresponding to the cervical, middle and apical thirds of the root canal region prepared for the post. The specimens were submitted to the pushout test in a universal test machine at a speed of 0.5 mm/min and the maximum bond strength values were recorded and submitted to statistical analysis (p < 0.05). Analysis of variance (ANOVA) showed statistically significant difference between the cervical, middle and apical thirds only for the Panavia 21 cement group, in which the apical third presented a lower mean bond strength value than the cervical and middle thirds (the TukeyÂs test). When the bond strength in each region of the root was compared to assess the cementing materials, the analysis of variance (ANOVA) showed statistically significant different for the three regions of the canal. For the middle and apical thirds, the Panavia 21 cement presented significantly lower mean bond strength than the Single Bond 2/RelyX ARC and RelyX Unicem cements, these being statistically equal between them. For the cervical third, RelyX Unicem cement presented higher bond strength values than the Panavia 21 cement and the Single Bond 2/RelyX ARC cement was statistically equal to the other two materials
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Higashi, Cristian. "Avaliação da dureza e módulo de elasticidade da interface de união resina – dentina utilizando a técnica de nanoindentação." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2008. http://tede2.uepg.br/jspui/handle/prefix/1747.
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The aim of this study was to assess the hardness and elastic modulus of resin-dentin bonding area formed by an ethanol/water-based (Adper TM Single Bond 2 [SB]) and an acetone-based system (One Step Plus [OS]), under different moisture conditions and application methods. On 24 human molars, a flat superficial dentin surface was exposed by wet abrasion. Two coats of SB or OS adhesive were applied on either a dry (D) or rewetted surface (W), under active (AA) or inactive (IA) application. After polymerization of the adhesives (600 mW/cm2/20 s), composite build-ups were constructed incrementally and specimens were stored in water (24 h). They were cross-sectioned perpendicular to the resin-dentin interface to obtain slices of 1.5 mm thickness that were embedded and polished before the test. Nanoindentations were made on composite resin, adhesive system, hybrid layer and dentin regions. The results of hardness and elastic modulus (GPa) of adhesive system and hybrid layer were analyzed by a three-way ANOVA and Tukey’s multiple comparison tests (α=0.05). The mean and standard deviation of hardness and elastic modulus values of composite resin were (1.02 ± 0.07) and (14.94 ± 0.67) respectively. In dentin, the hardness was (0.69 ± 0.10) and the elastic modulus (17.94 ± 1.84). In the adhesive layer, the highest hardness (0.38 ± 0.06) and elastic modulus (6.93 ± 0.93) of SB were obtained in W group. In this same area, the elastic modulus of OS (5.91 ± 1.12) was lowest in AA group. In the hybrid layer, the hardness of both adhesive systems was highest in AA group, however statistically significant just for OS (0.51 ± 0.2). In D group the highest hardness (0.47 ± 0.24) and elastic modulus (10.98 ± 4.65) of hybrid layer were obtained with AA. It was concluded that the active application of both adhesives in dry dentin resulted in higher hardness and elastic modulus values in the hybrid layer and the moisture increased hardness and elastic modulus values of Adper TM Single Bond 2 in the adhesive layer.
O objetivo deste trabalho foi avaliar a dureza e módulo de elasticidade da interface de união resina-dentina formado por adesivos convencionais de 2 passos à base de água/etanol (Adper TM Single Bond 2 [SB]) e à base de acetona (One Step Plus [OS]), variando a umidade dentinária e forma de aplicação dos mesmos. 24 terceiros molares humanos foram lixados para a obtenção de uma superfície dentinária plana. Duas gotas do adesivo SB ou OS foram aplicadas de forma ativa (AA) ou inativa (AI) sobre uma dentina seca (S) ou reumedecida (U). Após a fotopolimerização dos adesivos (600 mW/cm2 / 20 s) os dentes foram restaurados incrementalmente e armazenados em água destilada por 24 h. Cortes perpendiculares à interface de união foram realizados para obtenção de fatias de aproximadamente 1,5 mm de espessura, que foram embutidas e polidas previamente ao teste. Nanoindentações foram realizadas nas regiões da resina composta, sistema adesivo, camada híbrida e dentina. Os valores de dureza e módulo de elasticidade (GPa) do sistema adesivo e camada híbrida foram submetidos a uma análise de variância de 3 fatores de medidas repetidas e ao teste de comparações múltiplas de Tukey (α=0,05). A média e desvio padrão dos valores de dureza e módulo de elasticidade da resina composta (GPa) foram (1,02 ± 0,07) e (14,94 ± 0,67), respectivamente. Na dentina, a dureza foi (0,69 ± 0,10) e o módulo de elasticidade (17,94 ± 1,84). Na camada de adesivo, os maiores valores de dureza (0,38 ± 0,06) e módulo de elasticidade (6,93 ± 0,93) do SB foram obtidos no grupo U. Nesta mesma região, o módulo de elasticidade do OS (5,91 ± 1,12) foi menor para o grupo AA. Na região da camada híbrida, a dureza de ambos os sistemas adesivos foi maior no grupo AA, porém significativamente somente para o OS (0,51 ± 0,2). No grupo S os maiores valores de dureza (0,47 ± 0,24) e módulo de elasticidade (10,98 ± 4,65) da camada híbrida foram obtidos com AA. Concluiu-se que a aplicação ativa de ambos os sistemas adesivos em substrato dentinário seco resultou nos maiores valores de dureza e módulo de elasticidade na região da camada híbrida e a umidade dentinária influenciou positivamente nos valores de dureza e módulo de elasticidade do sistema adesivo Adper TM Single Bond 2 na região da camada de adesivo.
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Martin, Júnior Manoel [UNESP]. "Sistemas adesivos convencional e autocondicionante: análise micromecânica tridimensional da interface dentina-adesivo." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/105580.
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martinjunior_m_dr_araca.pdf: 402142 bytes, checksum: ec08401476b3983abaa71ed519f0d4e8 (MD5)OBJETIVO: Avaliar a distribuição das tensões na interface dentina-adesivo variando o sistema adesivo, convencional e autocondicionante, através do método dos elementos finitos tridimensional. MATERIAL E MÉTODO: Foram elaborados 4 modelos no programa Solidworks 2007, sendo: Mc - representação de um espécime em dentina (41x41x82 μm) restaurado com resina composta (RC), apresentando camada de adesivo, camada híbrida (CH), TAGs, dentina peri-tubular, dentina intertubular parcialmente desmineralizada, dentina intertubular e prolongamento odontoblástico, simulando a formação da CH segundo o sistema adesivo convencional; Mr - idêntico ao Mc, com ramificações laterais do infiltrado do adesivo; Ma – idêntico ao Mc, sem TAGs, e com “smear plug”, simulando o sistema adesivo autocondicionante; Mat – idêntico ao Ma, com TAGs. Os modelos foram considerados isotrópicos, homogêneos e linearmente elásticos e a análise numérica foi realizada no ANSYS Workbench 10.0 para obtenção da máxima tensão principal (MAX) após aplicação de força de tração de 0,03 N perpendicular à superfície da RC. A base de todos os modelos foi fixada nos eixos x, y e z. RESULTADOS: A MAX foi maior para o sistema convencional. A presença da ramificação lateral aumentou a MAX na CH para o sistema convencional. Os TAGs modificaram a distribuição da MAX na camada de adesivo para o sistema autocondicionante. CONCLUSÃO: A CH para o sistema convencional apresentou maior MAX em comparação ao sistema autocondicionante. A presença das ramificações laterais do adesivo aumentaram a tensão na CH para o sistema convencional.
OBJECTIVE: The aim of this study was to evaluate the stress distribution in the hybrid layer varying the adhesive system (total each and self-etching systems) using three-dimensional finite element analysis (FE). METHODS: 4 FE models (M) were developed in Solidworks 2007: Mc - representation of a specimen of dentin (41x41x82 μm) restored with composite resin (RC), showing the adhesive layer, hybrid layer (HL), TAGs, peri-tubular dentin, intertubular dentin in order to simulate simulating the HL according to the total-etch adhesive system; Mr - similar to Mc, with lateral branches of the adhesive; Ma – similar to Mc, without TAGs and showing the smear plug in order to simulate the environment for the self-ethcing adhesive system; Mat – similar to Ma, with TAGs. The models were considered isotropic, homogeneous and linearly elastic and numerical analysis was performed in ANSYS Workbench 10.0 to obtain the maximum principal stress (MAX) after application of a tension force of 0.03N perpendicular to the surface of the RC. The botton of all models was fixed in x, y and z axis. RESULTS: The highest MAX in HL was observed in the total etching system. The lateral branches increased the MAX in HL. The TAGs had a little influence on the stress distribution in self-ethching system. CONCLUSION: The HL for the total-etch system showed MAX higher in comparison with the self-etch system. The presence of TAGs increased the MAX in the HL for the total-etch system.
Book chapters on the topic "Interface de-bonding"
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"predicting the permissible external loading that a diamond-coated cutting tool can withstand without premature de-bonding. 3.1.6. Wear mechanisms. The failure of CVD diamond-coated inserts during machining can be in the form of flaking (interfacial failure) or abrasive wear (gradual cohesive failure) [22]. Ideally, a test of superb adhesion is when the diamond coating fully deteriorates by wear rather than flaking. Flaking will occur primarily due to poor adhesion between the diamond coating and the carbide substrate [6]. Therefore, flaking is clearly undesirable because the benefit of using a diamond coating is lost, except for the chip breaking assistance of faceted diamond crystals at the rake surface [29, 75]. If the adhesion strength of the CVD diamond coating is sufficient to withstand the machining stresses, then the abrasive action between the workpiece material and the diamond coating becomes the primary failure mechanism. Unless the CVD diamond coating is polished, a two-step wear mechanism is ex pected to occur. The first step is caused by the initial high surface roughness of the CVD diamond coating in which crack initiation occurs at the surface. The mecha nism that describes such behavior was proposed by Gunnars and Alahelisten [56]. They described a three-zone wear model as shown in Fig. 6. In this model, the role of residual stresses becomes significant in controlling crack propagation from the surface to the interface that could lead to interface failure (flaking). As outlined earlier, the high total compressive residual stress present in CVD diamond coatings on carbide inserts was assumed to be biaxial and oriented parallel to the interface. Wear starts to occur at the surface, which, because of geometry, allows stress to relax. A crack is more likely to initiate at protruding grains in zone I and propa gate preferentially along the (111) easy cleavage planes of diamond. The geometry at deeper depths, however, prevents the compressive residual stress from relaxing. Therefore, as the crack propagates deeper in the coating, it encounters higher com pressive stresses that cause the cracks to redirect their paths deviating from cleavage planes to a direction parallel to the interface in region II. The high compressive stress now causes cracks to propagate fast parallel to the interface resulting in a smooth surface in region III. Due to the smoother surface, fewer asperities will be present and it becomes harder to nucleate cracks." In Adhesion Aspects of Thin Films, Volume 1, 100–139. CRC Press, 2014. http://dx.doi.org/10.1201/b11971-20.
Full textConference papers on the topic "Interface de-bonding"
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Shi, Jun, Jianfeng Shi, Xinyu Nie, Yue Zhang, Guangzhong Li, Hanxin Chen, Yibin He, and Qingjun Wang. "Modeling the Interfacial De-Bonding Behavior Between Steel Wire and Adhesive." In ASME 2018 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/pvp2018-84379.
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A polyethylene pipe reinforced by winding steel wires (PSP) has been widely used in petroleum, chemical engineering, and water supply, etc. The PSP has outstanding mechanical properties due to its unique composite structure. However, according to earlier research, interfacial de-bonding between steel wire and adhesive is the cause for bulging failure of PSP joint, which is more likely to occur when the temperature and inner pressure increases to some extent in the application. In this study, the interfacial behavior between steel wire and adhesive was investigated and the interfacial failure process was analyzed. The pull-out test was conducted using specimens that were manufactured following PSP process parameters. Finite element models were established to represent the mechanical behavior and the de-bonding failure process of the steel-polymer interface. Contact surface with cohesive behavior based cohesive zone model was utilized to characterize the interfacial properties. The interfacial de-bonding failure process included stick-slip interaction and frictional sliding interaction. Both the stick-slip interaction and the adhesive-friction transition were modeled in the simulation. Results were presented in terms of pull-out load-displacement relationships, maximum pull-out force, and nonlinear stress distributions. The simulation result agreed well with the experimental result.
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Chen, Yong, and Wei Dong. "Parametric Studies of Nonlinear Damping Behavior of APS Thermal Barrier Coatings Based on Cohesive Interface Model." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-69343.
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Thermal barrier coatings (TBCs) could reduce the temperature of the turbine blades and allow them working at higher temperatures, which leads to higher durability and reliability of turbine blades, and improves engine performance and fuel efficiency. Recent researches shown that thermal barrier coatings have very good damping properties, which means it could also improve the high cycle fatigue (HCF) life of the turbine blades. Previous studies found that damping of air plasma spray (APS) thermal barrier coatings exhibit non-linearities (amplitude-dependent) due to its microstructures, which consists of several layers of splats with inter- and intra-microstructural micro-cracks. The main purpose of this paper is on the application of a bilinear cohesive interface model to simulate the microstructural features, the damage process and the contact friction between the interfaces of microstructural faults in APS ceramic topcoat. A representative volume element (RVE) model which coupled with the cohesive interface model is built and parametric relations, in terms of interface strength and stiffness, vibration amplitude and vibration cycles, are computed in this paper for understanding the effect of interfacial degradation, de-bonding, sliding, and contact friction between the interfaces of microstructural faults on the nonlinear damping properties. The calculation results could provide a fundamental understanding of the mechanisms responsible for the observed nonlinear energy dissipation and damping properties in APS ceramic coatings.
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Nargund, Shrikant. "Evaluation of Stress Wave Attenuation in a Polymer Matrix Composite Using Finite Element Analysis Technique." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-67055.
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The dynamic behavior of polymer composites is significantly affected by the properties of their micro constituents including shape and size of inclusions and inclusions/matrix adhesion properties. Wave propagation through such a composite is a complex phenomenon as it includes random scattering, absorption and transmittance of the incident wave and is dependent upon factors such as the properties, size and placement of the inclusions inside the matrix. Finite element modeling provides a viable approach for investigating the effects of micro constituent structure on the dynamic behavior of polymer composites. In this paper, we investigate the stress wave attenuation characteristics of a particulate polymer matrix composite using Finite Element (FE) analysis approach. The wave attenuation of ultrasonic sinusoidal waves of frequency ranging from 1 MHz to 4 MHz is evaluated for different FE models. The spherical inclusions are randomly distributed inside the polymer matrix with a certain minimum distance apart from each other. Inclusion-Matrix adhesion properties are studied by modeling a small region at the interface of inclusions and matrix known as interphase region. The interphase region is modeled explicitly using the cohesive zone modeling approach to study how the properties of this region will affect the wave attenuation characteristics of the polymer composite. Cohesive zone models are governed by traction separation law which helps in the measurement of the inclusion-matrix bonding strength and also allow the study of de-bonding at the interface in the critically stressed region produced due application of load. Thus the FE models consist of three phases; polymer matrix, particulate inclusions and the interphase region. Various three dimensional FE models are created using 3D tetrahedral/hexahedral elements by varying the radius of the spherical inclusions and by varying volume fraction of the inclusions. The analyses are performed using a general purpose finite element software LS-Dyna. A rate dependent viscoelastic material model with four terms in prony series expansion is used for modeling the polymer matrix. A linear elastic isotropic material model is used for modeling the inclusions. The wave attenuation is measured as reduction in the amplitude of the wave as it passes through the composite. A comparison of results for various models is done to check for general trend of attenuation coefficient as a function of size of inclusions, volume fraction of inclusions, frequency of loading and interphase region properties. Results show that volume fraction and load frequency have a maximum effect on the wave attenuation coefficient. Interphase region stiffness and interface de-bonding also plays an important role in attenuation characteristics of the polymer composite.
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Ju, Jaehyung, Roger J. Morgan, and J. N. Reddy. "Thermo-Mechanical Analysis of Composites Under Combined Conduction Heating and Large Deflection Bending." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81262.
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A novel conduction heating apparatus that combines thermal loading with large deflection bending is introduced, and its effectiveness for thermo-mechanical stress analysis was investigated. By clamping composite specimens (M40J/PMR-II-50, [0,90]s, a uni-tape cross-ply) on the radial sides of half cylinders having two different radii (78.74mm and 37.96mm), three different in-plane strains including a no strain condition were applied to the composites. Three different thermal loading experiments, 1) 23°C to −196°C to 250°C, 2) 23°C to 250°C, and 3) 23°C to −196°C were performed as a function of mechanical in-plane strain levels. The apparatus was excellent enough to generate cracks related to the in-plane stresses (or strains) on plies. The quadratic failure criteria solution based on the thermal residual stresses shows a good agreement with the experimental results at low temperatures, but does not supply a good agreement at high temperatures. A weak adhesion of fiber/matrix interface at high temperatures (250°C) might cause the de-bonding at the interface and subsequent exposure to −196°C caused the intensive crack propagation.
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Sahadi, Beatriz, Marcelo Giannini, Maicon Sebold, and Carolina André. "Analysis of dentin bond strength and bonding interface using alternative conditioners." In Congresso de Iniciação Científica UNICAMP. Universidade Estadual de Campinas, 2019. http://dx.doi.org/10.20396/revpibic2720193057.
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Lampropoulos, Andreas P., Neil Maisuria, and Ourania T. Tsioulou. "Experimental investigation of the behaviour of Unreinforced Masonry strengthened with UHPFRC." In IABSE Congress, New York, New York 2019: The Evolving Metropolis. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/newyork.2019.0878.
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<p>The majority of existing Unreinforced Masonry (URM) structures are prone to weathering and catastrophic events such as earthquakes. The repair and strengthening of unreinforced masonry is a challenging task mainly due to the poor connection between the new materials and the existing substrate. The applications of Fibre Reinforced Polymers (FRP) for the strengthening of URM show that premature de-bonding and failure of the strengthened elements may occur.</p><p>In the current study, the application of Ultra High Performance Fibre Reinforcement Concrete (UHPFRC) layers for the improvement of the structural performance of URM specimens made of engineering bricks has been examined. Different percentages of steel fibres have been used and layers have been cast in connection with the URM specimens. Additional provisions for the improvement of the connection between the UHPFRC and the bricks have also been examined. The effect of the thickness of the layers and the effect of the fibre percentage of the UHPFRC have been investigated via flexural out of plane tests. The load mid- span deflection results have been recorded alongside with the slip at the UHPFRC-to-bricks interface and the results show that the structural performance of the URM specimens can be significantly improved with the proposed technique.</p>
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Alexandre Maffei Sartini Paulillo, Luis, and Guilherme Dos Santos Pinto. "Microntensile bond strenght of interface betwen dentin surface and indirect composite resin trough diferent bonding methods." In XXIII Congresso de Iniciação Científica da Unicamp. Campinas - SP, Brazil: Galoá, 2015. http://dx.doi.org/10.19146/pibic-2015-37327.
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Landwehr, Derek, Jim Watts, Daryl Crawmer, and Beth Aperavich. "Instrumented Strain-Gage Measurement for Coating Adhesion During Four-Point Bending." In ITSC2018, edited by F. Azarmi, K. Balani, H. Li, T. Eden, K. Shinoda, T. Hussain, F. L. Toma, Y. C. Lau, and J. Veilleux. ASM International, 2018. http://dx.doi.org/10.31399/asm.cp.itsc2018p0120.
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Abstract ASTM C633 has been an industry standard for determining thermal spray coating adhesion and cohesion strengths for nearly 40 years. The test, however, has several drawbacks that can greatly affect the results. The epoxies used cannot withstand stresses greater than 15,000psi, producing data that may suggest coatings cannot function beyond the epoxy threshold under uniaxial tensile loading, resulting in data that can only be used for general quality control or acceptance testing. Previously published data shows coatings functioning beyond C633 limits, yet there is no standardized test to show true functional stress limitations. A four-point bend test method with an instrumented strain-gage has been used to show coating adhesion well beyond the yield point of the steel substrates and beyond the C633 limits for three materials and thermal spray processes: electric arc sprayed aluminum bronze, plasma sprayed alumina, and HVOF WC/Co/Cr. A strain-gage is applied to a prepared coating surface on a bend bar and loaded under tension or compression. The MTS universal load frame force data is used to calculate the stress at the coating/substrate interface by beam theory equations, allowing for stress and strain vs displacement curves to be generated and directly compared against C633 data for coating adhesion strengths. The resulting data can indicate microscopic coating behavior (cracking, de-bonding) as a result of the test sensitivity and can ultimately be used as design data for the practicing engineer.
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Iizuka, Hiroshi, and Hideo Takahashi. "Extensional Stiffness Loss of Synchronous-Belt Cords." In ASME 2000 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/detc2000/ptg-14412.
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Abstract Synchronous belts consist of a rubber, a facing fabric and a helical cord that reinforces the belt stiffness. Therefore, the fatigue failure of the helical cord through the life is important for the stiffness loss of the belts. The purpose of this study is to discuss the mechanism of the extensional stiffness loss of the helical cord during the bending fatigue. The experimental results show that the extensional stiffness reduces up to about 50–60% of the initial value by the accumulation of the bending fatigue damage. The main damage is the de-bonding along the interfaces of the stranded glass filaments in the cord. The three dimensional FEM results show that the extensional stiffness is reduced by the initiation of the de-bonding. Then a simplified mechanical model is proposed to explain the stiffness loss considering the de-bonding. The model reasonably well explains the extensional stiffness loss.
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Shin, Moochul, and Hailing Yu. "Numerical Evaluation of Splitting Performance of Prestressed Concrete Prisms With Larger Diameter Prestressing Wires." In 2019 Joint Rail Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/jrc2019-1315.
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This numerical study focuses on evaluating the structural performance of prestressed concrete prisms with larger diameter (0.315 in) prestressing wires. More commonly used prestressing wires are the 0.209 in (5.32 mm) diameter wires for prestressed concrete crossties. However, there has been an interest to adopt larger diameter prestressing wires in order to provide higher prestress forces with the aim of mitigating the structural damage of prestressed concrete crossties. Previous experimental studies demonstrated that small-scale pretensioned concrete prisms had excellent correlation in bonding performance of concrete ties pretensioned with 0.209 in (5.32 mm) wires or three- or seven-wire strands. Using a finite element (FE) modeling approach, this study investigates the effects of 8 mm diameter prestressing wires on the splitting/bursting performance of prisms at the onset of de-tensioning of the wires. The studied parameters include geometrical/mechanical parameters such as thickness of the concrete cover, spacing between the wires, level of prestress forces, and concrete release strength in compression. Cohesive elements with a newly developed nonlinear bond-slip model are assigned to the interface between the prestressing wires and the surrounding concrete. The parameters for the bond-slip model are calibrated based on a simple pull-out test on concrete cylinders with the 0.315 in (8 mm) diameter wires. The simulation results are compared with the predicted splitting performance of prisms pretensioned with 0.209 in (5.32 mm) wires or seven-wire strands. Based on the FE analysis results, recommendations are made on the minimum concrete cover thickness and wire spacing required to achieve acceptable splitting/bursting performance in prestressed concrete prisms.