PURPOSE Fiber-reinforced composite (FRC) posts have gained much interest recently and understanding of their viscoelastic properties is important as they can be used in stress-bearing posterior restorations. The aim of this study was to evaluate the creep behavior and the viscoelastic properties of four commercial FRC posts under different temperatures and different storage conditions. METHOD...

The macroscopic viscoelastic behavior of collagen gel was studied through relaxation time distribution spectrum obtained from stress relaxation tests and viscoelastic constitutive modeling. Biaxial stress relaxation tests were performed to characterize the viscoelastic behavior of collagen gel crosslinked with Genipin solution. Relaxation time distribution spectrum was obtained from the stress ...

The viscoelastic properties of nine silicone-, polysulfide-, and polyether-based impression materials were determined using creep tests. During deformation the materials demonstrated linear viscoelastic behavior. The creep compliance curves, recovery, and percent set were calculated. Permanent deformation in these materials is a result of lack of recovery of elastic deformation as well as visco...

Structure– phenomenological hereditary model for prediction of viscoelastic properties of layered polymer composites based on hereditary mechanics and theory of laminated plates relationships was elaborated. Interrelated creep and relaxation constitutive equations of layered composite was derived on the basis of algebra of resolvent operators and matrix algorithms. On example of cross-ply carbo...

The interior transmission problem (ITP), which plays a fundamental role in inverse scattering theories involving penetrable defects, is investigated within the framework of mechanical waves scattered by piecewise-homogeneous, elastic or viscoelastic obstacles in a likewise heterogeneous background solid. For generality, the obstacle is allowed to be multiply connected, having both penetrable co...

In quasi-static tests, flexible polyurethane foam undergoing large compressive loading and unloading deformation exhibits highly nonlinear and viscoelastic behavior. In particular, the response in the first cycle is significantly different from the response in subsequent cycles. In addition, the stresses in the loading paths are higher than those in unloading paths. It is assumed that this quas...

In this paper, we consider an infinitely long viscoelastic thread in a tube filled with a Newtonian fluid. We apply Jeffreys model as the rheological relation for the thread. The thread moves due to a constant pressure gradient, but so slowly that the quasi-static creeping flow approximation is applicable. We investigate the effect of the ratio of viscosities, fluid elasticity, confinement and ...

The exact solution is given for the folding by compression of a viscoelastic layer embedded in a viscoelastic medium, under the assumption that there is perfect adherence between layer and medium. This solution agrees closely with the earlier result obtained by Biot which was based on the assumption that layer and medium could slip over each other. In a previous publication, Biot [l] has discus...

In the electronics industry epoxy molding compounds, underfills and adhesives are used for the packaging of electronic components. These materials are applied in liquid form, cured at elevated temperatures and then cooled down to room temperature. During these processing steps residual stresses are built up resulting from both cure and thermal shrinkage. These residual stresses add up to the st...