Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9952847 | Journal of the Mechanical Behavior of Biomedical Materials | 2018 | 7 Pages |
Abstract
This study aimed to characterize the fatigue behavior using two fatigue methods, boundary and staircase, and to predict the probability of failure (Pf) of zirconia-reinforced lithium silicate glass-ceramic (ZLS). Bar-shaped specimens of ZLS (18â¯Ã4â¯Ã1.2â¯mm) were fabricated. Thirty specimens were subjected to a three-point flexural strength test using a universal testing machine with 0.5â¯mm/min crosshead speed, in 37â¯Â°C distilled water. Flexural strength data were analyzed with Weibull statistics. Eighty-six bars were subjected to cyclic fatigue using boundary and staircase methods. Fatigue tests were performed in a pneumatic cycling machine (2â¯Hz, 37â¯Â°C distilled water) for 10â¯Â³â¯and 104 cycles. Fatigue data were analyzed using an inverse power law relationship and log normal-lifetime distribution. Fracture toughness (KIc) was determined using V-notched specimens (18â¯Ã4â¯Ã3â¯mm) and the short beam toughness method (nâ¯=â¯7). Vickers hardness (VH) was evaluated (4.9â¯N, 20â¯s). Fractographic and EDS analyses were also performed. ZLS showed a characteristic strength of 197â¯MPa, Weibull modulus of 4, VH of 6.67â¯GPa and KIc of 1.93â¯MPaâ¯m1/2. After 103 cycles, for both methods, there was a degradation of 78% of the initial strength. There was no significant degradation when the number of cycles increased from 103 to 104. Both methods resulted in similar Pf and precision at 40â¯MPa (~50% Pf). Yet, staircase shows good accuracy and precision in predicting the stress amplitude for a Pf near 50%; while boundary is also effective for Pf lower than 50%. The fatigue methods evaluated show similar accuracy and precision for predicting the Pf of a glass-ceramic when simulations were made in the range of stress levels and lifetimes used in the fatigue tests.
Keywords
Related Topics
Physical Sciences and Engineering
Engineering
Biomedical Engineering
Authors
Rodrigo Ottoni, Jason A. Griggs, Pedro H. Corazza, Álvaro Della Bona, Márcia Borba,