Abstract
The brittle fracture of a light-cured composite resin used in dental restoration was examined using a high-speed extensometer consisting of an optical fiber and a position-sensing detector (PSD). Single-edge-cracked specimens for tensile testing were fabricated by packing the composite between two rectangular plates of polymethyl methacrylate (PMMA). In order to study the dynamic effect of brittle fracture and the nonelastic effect of the material, the specimens were pin-loaded with a special jig so that they could split and fly apart in the loading direction after fracture. The flying height and residual deformation of the split specimen were measured to estimate the elastic energy E e and nonelastic energy E n, respectively. The fracture energy E f required to create a new fracture surface was obtained by subtracting E e and E n from the external work U ex applied to the specimen. The results showed that the ratio E f/ U ex was about 32% for the composite specimen over a wide range of the fracture load, while it was about 45% for the PMMA specimen. The energy release rate G f was also estimated using E f. The results indicated that, although G f increased with the fracture load, the increasing slope for the composite specimen was smaller than that of the PMMA specimen.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
