|
|
Effect of Interlayer Composition on Bond Strength between FRC Framework and Composite Veneer
Ibarra, Jonatanh José ; Pavelka,, Vladimír (oponent) ; Poláček, Petr (vedoucí práce)
composite materials and determine the influence of interlayer composition in the bond strength of the adhesive joint between FRC frameworks and composite veneer (PFC) for dental applications. Samples consisting in FRC rods made with commercial dimethacrylate and S-glass fibers and PFC made of a resin mixture (bis-GMA and PEGDMA) with barium glass powder as the filler were constructed. A total of 84 samples were prepared and measured. The samples were divided into five different groups. The first group was made of series of samples without any interlayer. The other four groups were divided according the composition of the interlayer (thickness and resins used). PFC of the specimens differed in the filler content (0, 10, 40 wt. %). The FRC rod was identical for all samples. The universal testing machine ZWICK Z010 was used to determine the shear strength of adhesive joint. A Scanning Electron Microscope (SEM) was used to study the loci of failure. Results show that the addition of an interlayer between the fiber-reinforced and particle filled composite, resulted in an improvement on the shear strength bond. This is very important, since the use of these materials in dentistry has been increasing in the last years and adhesion still reminds one of the biggest problems in clinical application.
|
|
|
Vliv složení na pevnost adheze mezi částicovými a vláknovými kompozity.
Trautmann, Radoslav ; Klement, Josef (oponent) ; Roubalíková, Lenka (oponent) ; Jančář, Josef (vedoucí práce)
This PhD thesis dealt with the influence of adhesion between fiber (FRC) and particulate (PFC) composite and the composition of both components on the mechanical properties and type of fracture of bi-material composite specimens under static loading. The influence of method of preparing a bi-material composite bodies on the strength of adhesion between the composite components was also investigated. To evaluate the mechanical properties of bi-material PFC / FRC specimens were used as 3 and 4 point bending test at room temperature and relative humidity of 70%. Modified pull-out test was used to measure the shear strength of adhesion between fiber and particulate composite. These results were correlated with the results of structural and fractographic analysis (TGA, SEM). Experimental data were analyzed using existing micromechanical models and found a relationship between stiffness of model bi-material bodies, composition and geometry of the arrangement of their components and adhesion strength between these components. Based on these results, the optimal method of layering and preparation of PFC/FRC bi-material bodies was proposed. The proposed procedures were used for the preparation and pre-clinical tests of frameworks of dental bridges.
|
|
|
Advanced Layered Composites for Dental Applications
Šedivý, Zbyněk ; Kučera, Jaroslav (oponent) ; Štěpánek, Petr (oponent) ; Jančář, Josef (vedoucí práce)
PhD thesis deals with mechanical response of advanced layered composites for dental applications. Different composition of layers as well as different particle filled composites and fiber reinforced composites were examined under static three-point bending at room temperature. The results were correlated with the outputs of dynamic thermomechanical analysis (DMTA) and optical analysis (high speed video recording and SEM). Experimental data were used as a comparison with the results of analytical and numerical models in order to determine the best suited model for prediction of basic mechanical properties of layered composites. Based on these analyses, basic rules for clinical applications in dentistry such as minimally invasive bridges
|
|
|
Výpočtové modelování a analýza šíření trhlin v keramických kompozitech obsahující residuální napětí
Černý, Hynek ; Majer, Zdeněk (oponent) ; Ševeček, Oldřich (vedoucí práce)
Diplomová práce se zabývá 3D výpočtovým modelováním šíření trhlin v částicových a vrstevnatých keramických kompozitech. Nejdříve byly prozkoumány všechny dostupné nástroje lomové mechaniky v softwaru ANSYS a jejich vhodnost pro řešení zadaného tématu. V další části byl analyzován průchod trhliny částicovými kompozity, kde byl kladen důraz na vliv odlišné tuhosti a teplotní roztažnosti všech složek kompozitu. Nejdříve byl průchod trhliny odladěn na modelu homogenního materiálu, následně byl přidán vliv odlišné tuhosti složek kompozitu a v poslední fázi byl přidán i vliv zbytkové napjatosti. Z dosažených výsledků bylo možné popsat vliv dříve vyjmenovaných faktorů na energii potřebnou pro šíření trhlin. Tento vytvořený model by měl být aplikovatelný na i na model reálného kompozitu, díky čemuž by mělo být možné kvantifikovat, jestli je kompozit z hlediska šíření trhlin odolnější než homogenní materiál. V poslední části práce byl analyzován průchod trhliny vrstevnatými keramickými lamináty, kde byl opět kladen důraz na rozdílné tuhosti a teplotní roztažnosti všech složek laminátu. V této části bylo využito velké výhody programu ANSYS Mechanical APDL, a to možnosti skriptování. Pomocí vytvořených maker byl vytvořen parametrický model, který byl po zadání vstupních údajů schopný sám vytvořit geometrii výpočtového modelu, zadat okrajové podmínky, vytvořit síť výpočtového modelu, nastavit analýzu a spustit výpočet. Vytvořený model lze pak využít například pro zjišťování zdánlivé lomové houževnatosti laminátů, díky které lze posoudit nakolik je použitá konfigurace vhodnější než použití homogenního materiálu.
|
|
|
Advanced Layered Composites for Dental Applications
Šedivý, Zbyněk ; Kučera, Jaroslav (oponent) ; Štěpánek, Petr (oponent) ; Jančář, Josef (vedoucí práce)
PhD thesis deals with mechanical response of advanced layered composites for dental applications. Different composition of layers as well as different particle filled composites and fiber reinforced composites were examined under static three-point bending at room temperature. The results were correlated with the outputs of dynamic thermomechanical analysis (DMTA) and optical analysis (high speed video recording and SEM). Experimental data were used as a comparison with the results of analytical and numerical models in order to determine the best suited model for prediction of basic mechanical properties of layered composites. Based on these analyses, basic rules for clinical applications in dentistry such as minimally invasive bridges
|
|
|
Vliv složení na pevnost adheze mezi částicovými a vláknovými kompozity.
Trautmann, Radoslav ; Klement, Josef (oponent) ; Roubalíková, Lenka (oponent) ; Jančář, Josef (vedoucí práce)
This PhD thesis dealt with the influence of adhesion between fiber (FRC) and particulate (PFC) composite and the composition of both components on the mechanical properties and type of fracture of bi-material composite specimens under static loading. The influence of method of preparing a bi-material composite bodies on the strength of adhesion between the composite components was also investigated. To evaluate the mechanical properties of bi-material PFC / FRC specimens were used as 3 and 4 point bending test at room temperature and relative humidity of 70%. Modified pull-out test was used to measure the shear strength of adhesion between fiber and particulate composite. These results were correlated with the results of structural and fractographic analysis (TGA, SEM). Experimental data were analyzed using existing micromechanical models and found a relationship between stiffness of model bi-material bodies, composition and geometry of the arrangement of their components and adhesion strength between these components. Based on these results, the optimal method of layering and preparation of PFC/FRC bi-material bodies was proposed. The proposed procedures were used for the preparation and pre-clinical tests of frameworks of dental bridges.
|
|
|
Effect of Interlayer Composition on Bond Strength between FRC Framework and Composite Veneer
Ibarra, Jonatanh José ; Pavelka,, Vladimír (oponent) ; Poláček, Petr (vedoucí práce)
composite materials and determine the influence of interlayer composition in the bond strength of the adhesive joint between FRC frameworks and composite veneer (PFC) for dental applications. Samples consisting in FRC rods made with commercial dimethacrylate and S-glass fibers and PFC made of a resin mixture (bis-GMA and PEGDMA) with barium glass powder as the filler were constructed. A total of 84 samples were prepared and measured. The samples were divided into five different groups. The first group was made of series of samples without any interlayer. The other four groups were divided according the composition of the interlayer (thickness and resins used). PFC of the specimens differed in the filler content (0, 10, 40 wt. %). The FRC rod was identical for all samples. The universal testing machine ZWICK Z010 was used to determine the shear strength of adhesive joint. A Scanning Electron Microscope (SEM) was used to study the loci of failure. Results show that the addition of an interlayer between the fiber-reinforced and particle filled composite, resulted in an improvement on the shear strength bond. This is very important, since the use of these materials in dentistry has been increasing in the last years and adhesion still reminds one of the biggest problems in clinical application.
|
host ::
RSS.