- ItemOpen AccessInfluences on Flexural Strength And Deformation Behavior of Led Cured Microhybrid And Nanofilled Dental Resin Composites(2015 Biomedical Engineering Society Annual Meeting, 2015, Tampa, Florida, United States, 2015) Osuntoki, A.A; Ajibola, O.O.E; Adeleye, O.A; Fakinlede, O.A; Adegbulugbe, C.IA major modern application of engineering materials is to support biological tissues. Mechanical tests that closely simulate the real world activity on these materials are the most reliable way of predicting their service performance under load bearing activity. Flexural strength is an important property for characterizing brittle materials because the test generates complex tensions by combining tensile stress, compression and shear. In general, high flexural strength is desired for restorative materials that support the occlusal forces of posterior teeth. Several factors such as curing time and strain rates as well as the constituents of the dental resin composites affect the flexural strength. Deformation behaviour of restorations, such as shrinkage and shearing from curing and mastication, have also been a major concern for clinicians because of void and crack formations in restored tooth structure which affects the mechanical properties of the resin composites.
- ItemOpen AccessViscoelastic-Viscoplastic Material Model for Nonlinear Deformation of Dental Resin Composites(21st International Conference on Computer Methods in Mechanics, 2015, Gdansk, Poland, 2015) Adeleye, O.A; Fakinlede, O.A; Ajiboye, J.S; Adegbulugbe, C.IThe rate-dependence, recoverable and irrecoverable nonlinear deformation behavior of microhybrid and nanofilled dental resin composites cured with the conventional light emitting diode (LED) and exponential light emitting diode (HiLED) composites under uniaxial loading is here presented. Experimental study based on displacement controlled multiple stress creep recovery (MSCR) tests revealed hysteresis loop in loading and unloading states indicating an inherent viscoelastic nature, and at stress values less than 4 MPa, rate dependent recoverable strains were observed. But at stress values higher than 4 MPa, irreversible strains were observed which also indicates viscoplasticity. Hence a viscoelastic-viscoplastic constitutive model can be used to represent the material deformation behavior for the dental resin composite.
- ItemOpen AccessSymbolic Nonlinear Analysis of Viscoelastic Pipes(International Conference on Innovations and Technology (IET 2011), 2010) Adeleye, O.A; Fakinlede, O.AIn this study, a novel application domain of symbolic computation of nonlinear finite element method using a viscoelastic pipes has been presented. The problem of geometric nonlinearity due to the effect of high temperature, large displacement, small strain and moderate rotation of viscoelastic pipes was modeled and validated with numerical, symbolic and graphical computation in a unified manner called symbolic analysis. The current study has shown that the symbolic computation is effective and efficient, it saves computation time which can be seen in the symbolically integrated element-stiffness matrices in the nonlinear finite element method which by-passes time-consuming numerical quadrature operation, especially as the number of Gauss points increases. The symbolic computation also gives the analyst more visibility with respect to the solution method and the engineer can then more easily grasp the inter-relationship of the problem variables, recognize the simplification to be made and do a better and more accurate job. The computer codes of the finite element formulation used in this work was generated through the symbolic programming of the finite element computer code in AceGen and AceFEM computer program.