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Niwut Juntavee - One of the best experts on this subject based on the ideXlab platform.

  • Flexural Strength of Different Monolithic Computer-Assisted Design and Computer-Assisted Manufacturing Ceramic Materials upon Different Thermal Tempering Processes.
    European Journal of Dentistry, 2020
    Co-Authors: Niwut Juntavee, Pithiwat Uasuwan
    Abstract:

    OBJECTIVE  Strength of ceramics related with sintering procedure. This study investigated the influence of different Tempering processes on flexural strength of three monolithic ceramic materials. MATERIALS AND METHODS  Specimens were prepared in bar-shape (width × length × thickness = 4 × 14 × 1.2 mm) from yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP, inCoris TZI [I]), zirconia-reinforced lithium silicate (ZLS, Vita Suprinity [V]), and lithium disilicate (LS2, IPS e.max CAD [E]), and sintered with different Tempering processes: slow (S), normal (N), and fast (F) cooling procedure (n = 15/group). Flexural strength (σ) was determined using three-point bending test apparatus at 1 mm/min crosshead speed. STATISTICAL ANALYSIS  The analysis of variance and Bonferroni's multiple comparisons were determined for significant difference (α = 0.05). Weibull analysis was applied for survival probability, Weibull modulus (m), and characteristics strength (σo). Microstructures were evaluated with scanning electron microscope and X-ray diffraction. RESULTS  The mean ± standard deviation (MPa) of σ, m, and σo were: 1,183.98 ± 204.26, 6.23, 1,271.80 for IS; 1,084.43 ± 204.79, 5.76, 1,170.08 for IN; 777.19 ± 99.77, 8.78, 819.96 for IF; 267.15 ± 32.71, 9.11, 281.48 for VS; 218.43 ± 38.46, 6.40, 234.23 for VN; 252.67 ± 37.58, 7.20, 269.23 for VF; 392.09 ± 37.91, 11.37, 409.23 for ES; 378.88 ± 55.38, 7.45, 403.11 for EN, and 390.94 ± 25.34, 16.00, 403.51 for EF. Thermal Tempering significantly affected flexural strength of Y-TZP (p 0.05). Y-TZP indicated significantly higher flexural strength upon slow Tempering than others. CONCLUSION  Enhancing flexural strength of Y-TZP can be achieved through slow Tempering process and was suggested as a process for monolithic zirconia. Strengthening of ZLS and LS2 cannot be accomplished through Tempering; thus, either S-, N-, or F- Tempering procedure can be performed. Nevertheless, to minimize sintering time, rapid Thermal Tempering is more preferable for both ZLS and LS2.

  • Flexural Strength of Different Monolithic Computer-Assisted Design and Computer-Assisted Manufacturing Ceramic Materials upon Different Thermal Tempering Processes.
    European journal of dentistry, 2020
    Co-Authors: Niwut Juntavee, Pithiwat Uasuwan
    Abstract:

     Strength of ceramics related with sintering procedure. This study investigated the influence of different Tempering processes on flexural strength of three monolithic ceramic materials.  Specimens were prepared in bar-shape (width × length × thickness = 4 × 14 × 1.2 mm) from yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP, inCoris TZI [I]), zirconia-reinforced lithium silicate (ZLS, Vita Suprinity [V]), and lithium disilicate (LS2, IPS e.max CAD [E]), and sintered with different Tempering processes: slow (S), normal (N), and fast (F) cooling procedure (n = 15/group). Flexural strength (σ) was determined using three-point bending test apparatus at 1 mm/min crosshead speed.  The analysis of variance and Bonferroni's multiple comparisons were determined for significant difference (α = 0.05). Weibull analysis was applied for survival probability, Weibull modulus (m), and characteristics strength (σo). Microstructures were evaluated with scanning electron microscope and X-ray diffraction.  The mean ± standard deviation (MPa) of σ, m, and σo were: 1,183.98 ± 204.26, 6.23, 1,271.80 for IS; 1,084.43 ± 204.79, 5.76, 1,170.08 for IN; 777.19 ± 99.77, 8.78, 819.96 for IF; 267.15 ± 32.71, 9.11, 281.48 for VS; 218.43 ± 38.46, 6.40, 234.23 for VN; 252.67 ± 37.58, 7.20, 269.23 for VF; 392.09 ± 37.91, 11.37, 409.23 for ES; 378.88 ± 55.38, 7.45, 403.11 for EN, and 390.94 ± 25.34, 16.00, 403.51 for EF. Thermal Tempering significantly affected flexural strength of Y-TZP (p < 0.05), but not either ZLS or LS2 (p > 0.05). Y-TZP indicated significantly higher flexural strength upon slow Tempering than others.  Enhancing flexural strength of Y-TZP can be achieved through slow Tempering process and was suggested as a process for monolithic zirconia. Strengthening of ZLS and LS2 cannot be accomplished through Tempering; thus, either S-, N-, or F- Tempering procedure can be performed. Nevertheless, to minimize sintering time, rapid Thermal Tempering is more preferable for both ZLS and LS2.

  • Influence of Thermal Tempering processes on color characteristics of different monolithic computer-assisted design and computer-assisted manufacturing ceramic materials.
    Journal of clinical and experimental dentistry, 2019
    Co-Authors: Niwut Juntavee, Pithiwat Uasuwan
    Abstract:

    The optical properties of dental restoration were influenced by the sintering parameters. This study investigated the effects of different Tempering processes on optical properties of three monolithic Cad-Cam ceramics. 135 monolithic material bars (4 mm width, 14 mm length, 1.2 mm thickness) were prepared from yttria-stabilized tetragonal zirconia polycrystalline (inCoris TZI, I), zirconia-reinforced lithium silicate (Vita Suprinity, V), and lithium disilicate glass (e.max CAD, E) ceramics, with different Tempering processes through slow (S), normal (N), and fast (F) cooling (n=15). The color appearance (∆EW), translucency parameter (TP), contrast ratio (CR), and opalescence parameter (OP) were determined. ANOVA and Bonferroni's multiple comparisons were determined for significant difference (α=0.05). The grain sizes were microscopically examined by scanning electron microscope. The phase transformation of zirconia was determined using X ray diffraction. The mean±sd of ΔEW, TP, CR, OP were 74.15±0.46, 1.26±0.15, 0.977±0.006, 1.02±0.12 for IS; 74.00±0.83, 1.27±0.19, 0.977±0.007, 1.02±0.12 for IN; 74.44±0.64, 1.70±0.08, 0.965±0.003, 1.30±0.07 for IF; 73.35±1.32, 2.44±0.24, 0.958±0.006, 2.10±0.20 for VS; 66.37±0.88, 4.05±0.3, 0.911±0.010, 3.18±0.20 for VN; 67.02±0.65, 3.79±0.17, 0.919±0.006, 3.01±0.13 for VF; 60.01±0.30, 5.53±0.17, 0.821±0.006, 2.71±0.06 for ES; 60.18±0.23, 5.49±0.17, 0.822±0.006, 2.66±0.05 for EN; and 59.82±0.26, 5.36±0.06, 0.826±0.002, 2.64±0.07 for EF. The color parameters were significantly affected by type of materials, Tempering processes, and their interactions (p<0.05). Phase transformation from t→m related with Tempering procedure for zirconia. Rapid Thermal Tempering process of Y-TZP resulted in larger grain size and t→m phase transformation leading to higher translucency. To achieve optimum translucency, a fast Thermal Tempering process was suggested for inCoris TZI and IPS e.max CAD, whilst a normal Tempering process was recommended for Vita Suprinity. Key words:Color, cooling process, contrast, opalescence, Thermal Tempering, translucency.

  • influence of Thermal Tempering processes on color characteristics of different monolithic computer assisted design and computer assisted manufacturing ceramic materials
    Journal of Clinical and Experimental Dentistry, 2019
    Co-Authors: Niwut Juntavee, Pithiwat Uasuwan
    Abstract:

    Background The optical properties of dental restoration were influenced by the sintering parameters. This study investigated the effects of different Tempering processes on optical properties of three monolithic Cad-Cam ceramics. Material and Methods 135 monolithic material bars (4 mm width, 14 mm length, 1.2 mm thickness) were prepared from yttria-stabilized tetragonal zirconia polycrystalline (inCoris TZI, I), zirconia-reinforced lithium silicate (Vita Suprinity, V), and lithium disilicate glass (e.max CAD, E) ceramics, with different Tempering processes through slow (S), normal (N), and fast (F) cooling (n=15). The color appearance (∆EW), translucency parameter (TP), contrast ratio (CR), and opalescence parameter (OP) were determined. ANOVA and Bonferroni's multiple comparisons were determined for significant difference (α=0.05). The grain sizes were microscopically examined by scanning electron microscope. The phase transformation of zirconia was determined using X ray diffraction. Results The mean±sd of ΔEW, TP, CR, OP were 74.15±0.46, 1.26±0.15, 0.977±0.006, 1.02±0.12 for IS; 74.00±0.83, 1.27±0.19, 0.977±0.007, 1.02±0.12 for IN; 74.44±0.64, 1.70±0.08, 0.965±0.003, 1.30±0.07 for IF; 73.35±1.32, 2.44±0.24, 0.958±0.006, 2.10±0.20 for VS; 66.37±0.88, 4.05±0.3, 0.911±0.010, 3.18±0.20 for VN; 67.02±0.65, 3.79±0.17, 0.919±0.006, 3.01±0.13 for VF; 60.01±0.30, 5.53±0.17, 0.821±0.006, 2.71±0.06 for ES; 60.18±0.23, 5.49±0.17, 0.822±0.006, 2.66±0.05 for EN; and 59.82±0.26, 5.36±0.06, 0.826±0.002, 2.64±0.07 for EF. The color parameters were significantly affected by type of materials, Tempering processes, and their interactions (p<0.05). Phase transformation from t→m related with Tempering procedure for zirconia. Conclusions Rapid Thermal Tempering process of Y-TZP resulted in larger grain size and t→m phase transformation leading to higher translucency. To achieve optimum translucency, a fast Thermal Tempering process was suggested for inCoris TZI and IPS e.max CAD, whilst a normal Tempering process was recommended for Vita Suprinity. Key words:Color, cooling process, contrast, opalescence, Thermal Tempering, translucency.

  • Influence of Thermal Tempering processes on color characteristics of different monolithic computer-assisted design and computer-assisted manufacturing ceramic materials.
    Journal of Clinical and Experimental Dentistry, 2019
    Co-Authors: Niwut Juntavee, Pithiwat Uasuwan
    Abstract:

    Background The optical properties of dental restoration were influenced by the sintering parameters. This study investigated the effects of different Tempering processes on optical properties of three monolithic Cad-Cam ceramics. Material and Methods 135 monolithic material bars (4 mm width, 14 mm length, 1.2 mm thickness) were prepared from yttria-stabilized tetragonal zirconia polycrystalline (inCoris TZI, I), zirconia-reinforced lithium silicate (Vita Suprinity, V), and lithium disilicate glass (e.max CAD, E) ceramics, with different Tempering processes through slow (S), normal (N), and fast (F) cooling (n=15). The color appearance (∆EW), translucency parameter (TP), contrast ratio (CR), and opalescence parameter (OP) were determined. ANOVA and Bonferroni's multiple comparisons were determined for significant difference (α=0.05). The grain sizes were microscopically examined by scanning electron microscope. The phase transformation of zirconia was determined using X ray diffraction. Results The mean±sd of ΔEW, TP, CR, OP were 74.15±0.46, 1.26±0.15, 0.977±0.006, 1.02±0.12 for IS; 74.00±0.83, 1.27±0.19, 0.977±0.007, 1.02±0.12 for IN; 74.44±0.64, 1.70±0.08, 0.965±0.003, 1.30±0.07 for IF; 73.35±1.32, 2.44±0.24, 0.958±0.006, 2.10±0.20 for VS; 66.37±0.88, 4.05±0.3, 0.911±0.010, 3.18±0.20 for VN; 67.02±0.65, 3.79±0.17, 0.919±0.006, 3.01±0.13 for VF; 60.01±0.30, 5.53±0.17, 0.821±0.006, 2.71±0.06 for ES; 60.18±0.23, 5.49±0.17, 0.822±0.006, 2.66±0.05 for EN; and 59.82±0.26, 5.36±0.06, 0.826±0.002, 2.64±0.07 for EF. The color parameters were significantly affected by type of materials, Tempering processes, and their interactions (p

Pithiwat Uasuwan - One of the best experts on this subject based on the ideXlab platform.

  • Flexural Strength of Different Monolithic Computer-Assisted Design and Computer-Assisted Manufacturing Ceramic Materials upon Different Thermal Tempering Processes.
    European Journal of Dentistry, 2020
    Co-Authors: Niwut Juntavee, Pithiwat Uasuwan
    Abstract:

    OBJECTIVE  Strength of ceramics related with sintering procedure. This study investigated the influence of different Tempering processes on flexural strength of three monolithic ceramic materials. MATERIALS AND METHODS  Specimens were prepared in bar-shape (width × length × thickness = 4 × 14 × 1.2 mm) from yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP, inCoris TZI [I]), zirconia-reinforced lithium silicate (ZLS, Vita Suprinity [V]), and lithium disilicate (LS2, IPS e.max CAD [E]), and sintered with different Tempering processes: slow (S), normal (N), and fast (F) cooling procedure (n = 15/group). Flexural strength (σ) was determined using three-point bending test apparatus at 1 mm/min crosshead speed. STATISTICAL ANALYSIS  The analysis of variance and Bonferroni's multiple comparisons were determined for significant difference (α = 0.05). Weibull analysis was applied for survival probability, Weibull modulus (m), and characteristics strength (σo). Microstructures were evaluated with scanning electron microscope and X-ray diffraction. RESULTS  The mean ± standard deviation (MPa) of σ, m, and σo were: 1,183.98 ± 204.26, 6.23, 1,271.80 for IS; 1,084.43 ± 204.79, 5.76, 1,170.08 for IN; 777.19 ± 99.77, 8.78, 819.96 for IF; 267.15 ± 32.71, 9.11, 281.48 for VS; 218.43 ± 38.46, 6.40, 234.23 for VN; 252.67 ± 37.58, 7.20, 269.23 for VF; 392.09 ± 37.91, 11.37, 409.23 for ES; 378.88 ± 55.38, 7.45, 403.11 for EN, and 390.94 ± 25.34, 16.00, 403.51 for EF. Thermal Tempering significantly affected flexural strength of Y-TZP (p 0.05). Y-TZP indicated significantly higher flexural strength upon slow Tempering than others. CONCLUSION  Enhancing flexural strength of Y-TZP can be achieved through slow Tempering process and was suggested as a process for monolithic zirconia. Strengthening of ZLS and LS2 cannot be accomplished through Tempering; thus, either S-, N-, or F- Tempering procedure can be performed. Nevertheless, to minimize sintering time, rapid Thermal Tempering is more preferable for both ZLS and LS2.

  • Flexural Strength of Different Monolithic Computer-Assisted Design and Computer-Assisted Manufacturing Ceramic Materials upon Different Thermal Tempering Processes.
    European journal of dentistry, 2020
    Co-Authors: Niwut Juntavee, Pithiwat Uasuwan
    Abstract:

     Strength of ceramics related with sintering procedure. This study investigated the influence of different Tempering processes on flexural strength of three monolithic ceramic materials.  Specimens were prepared in bar-shape (width × length × thickness = 4 × 14 × 1.2 mm) from yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP, inCoris TZI [I]), zirconia-reinforced lithium silicate (ZLS, Vita Suprinity [V]), and lithium disilicate (LS2, IPS e.max CAD [E]), and sintered with different Tempering processes: slow (S), normal (N), and fast (F) cooling procedure (n = 15/group). Flexural strength (σ) was determined using three-point bending test apparatus at 1 mm/min crosshead speed.  The analysis of variance and Bonferroni's multiple comparisons were determined for significant difference (α = 0.05). Weibull analysis was applied for survival probability, Weibull modulus (m), and characteristics strength (σo). Microstructures were evaluated with scanning electron microscope and X-ray diffraction.  The mean ± standard deviation (MPa) of σ, m, and σo were: 1,183.98 ± 204.26, 6.23, 1,271.80 for IS; 1,084.43 ± 204.79, 5.76, 1,170.08 for IN; 777.19 ± 99.77, 8.78, 819.96 for IF; 267.15 ± 32.71, 9.11, 281.48 for VS; 218.43 ± 38.46, 6.40, 234.23 for VN; 252.67 ± 37.58, 7.20, 269.23 for VF; 392.09 ± 37.91, 11.37, 409.23 for ES; 378.88 ± 55.38, 7.45, 403.11 for EN, and 390.94 ± 25.34, 16.00, 403.51 for EF. Thermal Tempering significantly affected flexural strength of Y-TZP (p < 0.05), but not either ZLS or LS2 (p > 0.05). Y-TZP indicated significantly higher flexural strength upon slow Tempering than others.  Enhancing flexural strength of Y-TZP can be achieved through slow Tempering process and was suggested as a process for monolithic zirconia. Strengthening of ZLS and LS2 cannot be accomplished through Tempering; thus, either S-, N-, or F- Tempering procedure can be performed. Nevertheless, to minimize sintering time, rapid Thermal Tempering is more preferable for both ZLS and LS2.

  • Influence of Thermal Tempering processes on color characteristics of different monolithic computer-assisted design and computer-assisted manufacturing ceramic materials.
    Journal of clinical and experimental dentistry, 2019
    Co-Authors: Niwut Juntavee, Pithiwat Uasuwan
    Abstract:

    The optical properties of dental restoration were influenced by the sintering parameters. This study investigated the effects of different Tempering processes on optical properties of three monolithic Cad-Cam ceramics. 135 monolithic material bars (4 mm width, 14 mm length, 1.2 mm thickness) were prepared from yttria-stabilized tetragonal zirconia polycrystalline (inCoris TZI, I), zirconia-reinforced lithium silicate (Vita Suprinity, V), and lithium disilicate glass (e.max CAD, E) ceramics, with different Tempering processes through slow (S), normal (N), and fast (F) cooling (n=15). The color appearance (∆EW), translucency parameter (TP), contrast ratio (CR), and opalescence parameter (OP) were determined. ANOVA and Bonferroni's multiple comparisons were determined for significant difference (α=0.05). The grain sizes were microscopically examined by scanning electron microscope. The phase transformation of zirconia was determined using X ray diffraction. The mean±sd of ΔEW, TP, CR, OP were 74.15±0.46, 1.26±0.15, 0.977±0.006, 1.02±0.12 for IS; 74.00±0.83, 1.27±0.19, 0.977±0.007, 1.02±0.12 for IN; 74.44±0.64, 1.70±0.08, 0.965±0.003, 1.30±0.07 for IF; 73.35±1.32, 2.44±0.24, 0.958±0.006, 2.10±0.20 for VS; 66.37±0.88, 4.05±0.3, 0.911±0.010, 3.18±0.20 for VN; 67.02±0.65, 3.79±0.17, 0.919±0.006, 3.01±0.13 for VF; 60.01±0.30, 5.53±0.17, 0.821±0.006, 2.71±0.06 for ES; 60.18±0.23, 5.49±0.17, 0.822±0.006, 2.66±0.05 for EN; and 59.82±0.26, 5.36±0.06, 0.826±0.002, 2.64±0.07 for EF. The color parameters were significantly affected by type of materials, Tempering processes, and their interactions (p<0.05). Phase transformation from t→m related with Tempering procedure for zirconia. Rapid Thermal Tempering process of Y-TZP resulted in larger grain size and t→m phase transformation leading to higher translucency. To achieve optimum translucency, a fast Thermal Tempering process was suggested for inCoris TZI and IPS e.max CAD, whilst a normal Tempering process was recommended for Vita Suprinity. Key words:Color, cooling process, contrast, opalescence, Thermal Tempering, translucency.

  • influence of Thermal Tempering processes on color characteristics of different monolithic computer assisted design and computer assisted manufacturing ceramic materials
    Journal of Clinical and Experimental Dentistry, 2019
    Co-Authors: Niwut Juntavee, Pithiwat Uasuwan
    Abstract:

    Background The optical properties of dental restoration were influenced by the sintering parameters. This study investigated the effects of different Tempering processes on optical properties of three monolithic Cad-Cam ceramics. Material and Methods 135 monolithic material bars (4 mm width, 14 mm length, 1.2 mm thickness) were prepared from yttria-stabilized tetragonal zirconia polycrystalline (inCoris TZI, I), zirconia-reinforced lithium silicate (Vita Suprinity, V), and lithium disilicate glass (e.max CAD, E) ceramics, with different Tempering processes through slow (S), normal (N), and fast (F) cooling (n=15). The color appearance (∆EW), translucency parameter (TP), contrast ratio (CR), and opalescence parameter (OP) were determined. ANOVA and Bonferroni's multiple comparisons were determined for significant difference (α=0.05). The grain sizes were microscopically examined by scanning electron microscope. The phase transformation of zirconia was determined using X ray diffraction. Results The mean±sd of ΔEW, TP, CR, OP were 74.15±0.46, 1.26±0.15, 0.977±0.006, 1.02±0.12 for IS; 74.00±0.83, 1.27±0.19, 0.977±0.007, 1.02±0.12 for IN; 74.44±0.64, 1.70±0.08, 0.965±0.003, 1.30±0.07 for IF; 73.35±1.32, 2.44±0.24, 0.958±0.006, 2.10±0.20 for VS; 66.37±0.88, 4.05±0.3, 0.911±0.010, 3.18±0.20 for VN; 67.02±0.65, 3.79±0.17, 0.919±0.006, 3.01±0.13 for VF; 60.01±0.30, 5.53±0.17, 0.821±0.006, 2.71±0.06 for ES; 60.18±0.23, 5.49±0.17, 0.822±0.006, 2.66±0.05 for EN; and 59.82±0.26, 5.36±0.06, 0.826±0.002, 2.64±0.07 for EF. The color parameters were significantly affected by type of materials, Tempering processes, and their interactions (p<0.05). Phase transformation from t→m related with Tempering procedure for zirconia. Conclusions Rapid Thermal Tempering process of Y-TZP resulted in larger grain size and t→m phase transformation leading to higher translucency. To achieve optimum translucency, a fast Thermal Tempering process was suggested for inCoris TZI and IPS e.max CAD, whilst a normal Tempering process was recommended for Vita Suprinity. Key words:Color, cooling process, contrast, opalescence, Thermal Tempering, translucency.

  • Influence of Thermal Tempering processes on color characteristics of different monolithic computer-assisted design and computer-assisted manufacturing ceramic materials.
    Journal of Clinical and Experimental Dentistry, 2019
    Co-Authors: Niwut Juntavee, Pithiwat Uasuwan
    Abstract:

    Background The optical properties of dental restoration were influenced by the sintering parameters. This study investigated the effects of different Tempering processes on optical properties of three monolithic Cad-Cam ceramics. Material and Methods 135 monolithic material bars (4 mm width, 14 mm length, 1.2 mm thickness) were prepared from yttria-stabilized tetragonal zirconia polycrystalline (inCoris TZI, I), zirconia-reinforced lithium silicate (Vita Suprinity, V), and lithium disilicate glass (e.max CAD, E) ceramics, with different Tempering processes through slow (S), normal (N), and fast (F) cooling (n=15). The color appearance (∆EW), translucency parameter (TP), contrast ratio (CR), and opalescence parameter (OP) were determined. ANOVA and Bonferroni's multiple comparisons were determined for significant difference (α=0.05). The grain sizes were microscopically examined by scanning electron microscope. The phase transformation of zirconia was determined using X ray diffraction. Results The mean±sd of ΔEW, TP, CR, OP were 74.15±0.46, 1.26±0.15, 0.977±0.006, 1.02±0.12 for IS; 74.00±0.83, 1.27±0.19, 0.977±0.007, 1.02±0.12 for IN; 74.44±0.64, 1.70±0.08, 0.965±0.003, 1.30±0.07 for IF; 73.35±1.32, 2.44±0.24, 0.958±0.006, 2.10±0.20 for VS; 66.37±0.88, 4.05±0.3, 0.911±0.010, 3.18±0.20 for VN; 67.02±0.65, 3.79±0.17, 0.919±0.006, 3.01±0.13 for VF; 60.01±0.30, 5.53±0.17, 0.821±0.006, 2.71±0.06 for ES; 60.18±0.23, 5.49±0.17, 0.822±0.006, 2.66±0.05 for EN; and 59.82±0.26, 5.36±0.06, 0.826±0.002, 2.64±0.07 for EF. The color parameters were significantly affected by type of materials, Tempering processes, and their interactions (p

Laurent Daudeville - One of the best experts on this subject based on the ideXlab platform.

  • Point fixings in annealed and tempered glass structures: Modeling and optimization of bolted connections
    Engineering Structures, 2009
    Co-Authors: Fabrice Bernard, Laurent Daudeville
    Abstract:

    In the design of high load bearing elements made of tempered flat glass, connections cannot be avoided when large spans or high stiffness beams are considered. This paper investigates bolted connections in glass structures; the main objective is to determine the optimal joint. This work is performed through the determination of stress states due to both Thermal Tempering and in-plane loading. The modeling of the Thermal Tempering is performed with the FE software Abaqus and additional user subroutines. Experiments on industrial Tempering line with specific set-up allow the determination of the air flow in the hole and then of the forced convection coefficients. The radiative heat transfer is also modeled numerically and the semi-transparency of glass in the near infrared is considered. In order to calculate residual stresses, the visco-elasticity of glass and the structural relaxation phenomena are taken into account. The computed stresses are checked against photo-elastic measurements. As various holes are considered, this study allows to determine the hole geometry for which the Tempering process is the most effective. For the study of the consequences of in-plane loading, a large experimental campaign has been performed. The studied connection is derived from countersunk supports. The influences of different parameters as the hole geometry, the nature of the washer between glass and metallic connector as well as the glass-washer material friction coefficient were investigated. The modeling of these tests is performed with the FE software Abaqus. This modeling takes into account the ductility of the materials, the friction and the clearances between the parts. This modeling is validated thanks to failure stress measurements. The combination of modeling and experiments leads to identify optimal connection.

  • Calcul des contraintes résiduelles dans les zones d'assemblage de plaques en verre trempé
    Mecanique & Industries, 2005
    Co-Authors: Fabrice Bernard, Laurent Daudeville
    Abstract:

    Prediction of residual stresses near joints in tempered glass plates. This work deals with the use of glass as a real structural material and concerns more particularly the calculation of residual stresses due to Tempering in the vicinity of dowel type joints inserted into chamfered holes in the aim of predicting the load bearing capacity of such joints. This work presents numerical simulation results of the Thermal Tempering by the Finite Element Method in order to calculate transient and residual stresses near edges of a glass plate (2D calculation) and near holes (3D calculation). During Thermal Tempering, glass is considered as a viscoelastic material. The Narayanaswamy's model is used. It takes into account the structural relaxation phenomena. The particular difficulty is the correct modelling of heat transfers since transient and residual stresses strongly depend on the history of temperature within the plate, close to the edge and to the hole. Both the forced convection due to the blowing of air and the radiative heat transfer are modeled numerically. The semi-transparency of glass in the near infrared range is considered. The convective heat transfer coefficients on the edge and hole walls are identified thanks to a specific experimental set-up and validated from simulations of heat transfer tests. The computed residual stresses are checked against photo-elastic measurements. Such a work allows the optimization of the glass plate geometry in the vicinity of the joint in the aim of a maximum reinforcement.

  • Sur le dimensionnement des structures en verre trempé
    Revue Française de Génie Civil, 2002
    Co-Authors: Fabrice Bernard, Laurent Daudeville
    Abstract:

    This work deals with the use of glass as a real structural material, and concerns more particularly the detailed study of the potentiality of a connection by insertion of a steel dowel in a hole of a glass plate, in the aim of the making of long beams or beams with large inertia. The determination of the optimal geometry for such a connection passes first by the superposition of two stress states (the first one is generated by the Thermal Tempering and the second is due to the loading of the metallic connector in the plane of the glass plate). Then a design method ensuring the durability of the structure is proposed. MOTS-CLES : verre structural, connexions, trempe thermique, transferts de chaleur, elements finis, fractographie, photoelasticite

  • Residual Stresses Near Holes in Tempered Glass Plates
    Materials Science Forum, 2002
    Co-Authors: Laurent Daudeville, Frédéric Bernard
    Abstract:

    This work presents numerical simulation results of the Thermal Tempering by the Finite Element Method in order to calculate transient and residual stresses near edges of a glass plate (2D calculation) and near holes (3D calculation). During Thermal Tempering, glass ιs considered as a viscoelastic material. The Narayanaswamy's model is used. It takes into account the structural relaxation phenomena. The particular difficulty is the correct modelling of heat transfers since transient and residual stresses strongly depend on the history of temperature within the plate, close to the edge and the hole. Both the forced convection due to the blowing of air and the radiative heat transfer are modelled numerically. The semi-transparency of glass in the near infrared range is considered. The convective heat transfer coefficients on the edge and hole walls are identified thanks to a specific experimental set-up and validated from simulations of heat transfer tests. The computed residual stresses are checked against photo-elastic measurements.

  • Finite element computation of residual stresses near holes in tempered glass plates
    2001
    Co-Authors: Fabrice Bernard, Rene Gy, Laurent Daudeville
    Abstract:

    This work presents numerical results of the Thermal Tempering simulation by the finite element method in order to calculate residual stresses near edges of a glass plate (2D calculation) and near chamfered holes (3D calculation). During Thermal Tempering, glass is considered as a viscoelastic material. Narayanaswamy's model is used; it takes into account the structural relaxation phenomena. Particular difficulty is the correct modelling of heat transfers since residual stresses strongly depend on the history of temperature within the plate, close to the edges and in the vicinity of the hole. Both the forced convection due to the blowing of air and the radiative heat transfer are modelled numerically. The semi-transparency of glass in the near infrared range is considered. The convective heat transfer coefficients on the edge and hole walls are identified thanks to a specific experimental setup and validated from simulations of heat transfer tests. The computed residual stresses are checked against photoelastic measurements.

Chafik Karra - One of the best experts on this subject based on the ideXlab platform.

  • Study of the Influence of Thermal Tempering on the Bending Behavior of the Silico Soda Lime Glass Material
    2019
    Co-Authors: Souad Hamdoun, Mounir Kchaou, Chafik Karra
    Abstract:

    In this contribution, we examine the mechanical behavior of tempered soda-lime-silica glass plates and show that improvements in performance can be achieved through the change of the structural and mechanical properties. Tests of Thermal Tempering by air jet have been performed on glass plates of different dimensions. Three-point bending tests have been conducted on nontempered and fully tempered float glass plates of four different sizes. A parametric study on the thickness of the plate and the conditions of Tempering has been performed. The experimental results show that the Thermal Tempering improves the rupture resistance of glass plates. This experimental study has been supplemented by a numerical finite element simulation of the stress state which has shown a satisfactory comparison with experimental results. Finally, the numerical results show that the design deflection of tempered glass is much less than commonly assumed. In this contribution, we examine the mechanical behavior of tempered soda-lime-silica glass plates and show that improvements in performance can be achieved through the change of the structural and mechanical properties. Tests of Thermal Tempering by air jet have been performed on glass plates of different dimensions. Three-point bending tests have been conducted on nontempered and fully tempered float glass plates of four different sizes. A parametric study on the thickness of the plate and the conditions of Tempering has been performed. The experimental results show that the Thermal Tempering improves the rupture resistance of glass plates. This experimental study has been supplemented by a numerical finite element simulation of the stress state which has shown a satisfactory comparison with experimental results. Finally, the numerical results show that the design deflection of tempered glass is much less than commonly assumed.

  • Study of the Influence of Thermal Tempering on the Bending Behavior of the Silico Soda Lime Glass Material
    2012
    Co-Authors: Souad Hamdoun, Mounir Kchaou, Chafik Karra
    Abstract:

    In this contribution, we examine the mechanical behavior of tempered soda-lime-silica glass plates and show that improvements in performance can be achieved through the change of the structural and mechanical properties. Tests of Thermal Tempering by air jet have been performed on glass plates of different dimensions. Three-point bending tests have been conducted on nontempered and fully tempered float glass plates of four different sizes. A parametric study on the thickness of the plate and the conditions of Tempering has been performed. The experimental results show that the Thermal Tempering improves the rupture resistance of glass plates. This experimental study has been supplemented by a numerical finite element simulation of the stress state which has shown a satisfactory comparison with experimental results. Finally, the numerical results show that the design deflection of tempered glass is much less than commonly assumed. Keywords:  Thermal Tempering, glass, bending, stress, deflection

Pitsinee Serirojanakul - One of the best experts on this subject based on the ideXlab platform.

  • Influence of different veneering techniques and Thermal Tempering on flexural strength of ceramic veneered yttria partially stabilized tetragonal zirconia polycrystalline restoration.
    Journal of clinical and experimental dentistry, 2019
    Co-Authors: Niwut Juntavee, Pitsinee Serirojanakul
    Abstract:

    Different technique for ceramic veneering and Thermal Tempering process are expected to be a reason for alteration in strength of ceramic veneered zirconia. This study evaluates the effect of different veneering technique and varied Thermal Tempering process on flexural strength of ceramic veneered zirconia. Ceramic veneered zirconia bars (25 mm length, 4 mm width, 0.7&1.0mm of zirconia & ceramic thickness) were prepared from zirconia block (e.max® ZirCAD), sintered at 1500°C for 4 hours, and veneered with ceramics with different techniques including CAD-fused using e.max CAD® (C), Pressed-on using e.max® Zirpress (P), and layering using e.max® ceram (L), with different Tempering process through fast (F), medium (M), and slow (L) cooling (n=15). The specimens were determined for flexural strength on a universal testing machine. ANOVA and Bonferroni's multiple comparisons were used to determine for significant difference (α=0.05). Weibull analysis was applied for survival probability, Weibull modulus (m), and characteristics strength (σc). The interfaces were microscopically examined. The phase transformation of zirconia was determined using X ray diffraction. The mean±sd (MPa), m, σc of flexural strength were 922.06±83.45, 12.78, 958.32 for CF, 924.26±74.64, 14.28, 959.62 for CM, 930.25±92.42, 11.83, 970.83 for CS, 518.29±59.97, 10.11, 542.97 for PF, 516.50±67.51, 8.75, 539.17 for PM, and 520.51±42.38, 14.59, 544.51 for PS, 604.36±64.09, 11.28, 630.67 for LF, 583.81±56.95, 11.67, 609.81 for LM, 547.33±52.23, 12.19, 569.36 for LS. The flexural strength was significantly affected by veneering technique (p<0.05). No significant effect on flexural strength upon Tempering process was evidenced (P >0.05). Phase transformation from t→m related with veneering and Tempering procedure. Strength of ceramic veneered zirconia associated with different veneering techniques, but not directly related with Tempering process. CAD-on ceramic veneering zirconia is benefit for enhancing the strength of ceramic bilayer and was recommended as a method for ceramic veneering zirconia. Key words:CAD-CAM, cooling process, flexural strength, Thermal Tempering, zirconia.

  • Influence of different veneering techniques and Thermal Tempering on flexural strength of ceramic veneered yttria partially stabilized tetragonal zirconia polycrystalline restoration.
    Journal of Clinical and Experimental Dentistry, 2019
    Co-Authors: Niwut Juntavee, Pitsinee Serirojanakul
    Abstract:

    Background Different technique for ceramic veneering and Thermal Tempering process are expected to be a reason for alteration in strength of ceramic veneered zirconia. This study evaluates the effect of different veneering technique and varied Thermal Tempering process on flexural strength of ceramic veneered zirconia. Material and Methods Ceramic veneered zirconia bars (25 mm length, 4 mm width, 0.7&1.0mm of zirconia & ceramic thickness) were prepared from zirconia block (e.max® ZirCAD), sintered at 1500°C for 4 hours, and veneered with ceramics with different techniques including CAD-fused using e.max CAD® (C), Pressed-on using e.max® Zirpress (P), and layering using e.max® ceram (L), with different Tempering process through fast (F), medium (M), and slow (L) cooling (n=15). The specimens were determined for flexural strength on a universal testing machine. ANOVA and Bonferroni's multiple comparisons were used to determine for significant difference (α=0.05). Weibull analysis was applied for survival probability, Weibull modulus (m), and characteristics strength (σc). The interfaces were microscopically examined. The phase transformation of zirconia was determined using X ray diffraction. Results The mean±sd (MPa), m, σc of flexural strength were 922.06±83.45, 12.78, 958.32 for CF, 924.26±74.64, 14.28, 959.62 for CM, 930.25±92.42, 11.83, 970.83 for CS, 518.29±59.97, 10.11, 542.97 for PF, 516.50±67.51, 8.75, 539.17 for PM, and 520.51±42.38, 14.59, 544.51 for PS, 604.36±64.09, 11.28, 630.67 for LF, 583.81±56.95, 11.67, 609.81 for LM, 547.33±52.23, 12.19, 569.36 for LS. The flexural strength was significantly affected by veneering technique (p 0.05). Phase transformation from t→m related with veneering and Tempering procedure. Conclusions Strength of ceramic veneered zirconia associated with different veneering techniques, but not directly related with Tempering process. CAD-on ceramic veneering zirconia is benefit for enhancing the strength of ceramic bilayer and was recommended as a method for ceramic veneering zirconia. Key words:CAD-CAM, cooling process, flexural strength, Thermal Tempering, zirconia.