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SUMMARYThis work aims at evaluating the discretization errors associated to the ÿnite volume and ÿnite element methods of polymer melt ow in closed channels. Two strategies are discussed: (i) Richardson extrapolation and (ii) a posteriori error estimation based on projection=smoothing techniques. The numerical model accounts for the full interaction between the thermal e ects caused by viscous heating and the momentum di usion e ects dictated by a shear rate and temperature-dependent constitutive model. The simulations have been performed for the commercial polymer Polyacetal POM-M90-44.

In this work, aspects of discretization errors associated with finite volume (FV) and equivalent finite element (FE) modelling strategies are discussed within the framework of polymer melt flow. The computational approaches are based on the generalized Newtonian model in conjunction with Cross constitutive equation. The numerical examples illustrate one and two-dimensional fluid flows, in which the latter is discretized using structured quadrilateral elements / volumes. A study on the best strategy to compute non-linear viscosities at control volume boundaries is also presented for FV. Based on well established a posteriori error estimation techniques, it is demonstrated that, in this class of problems, FV discretization errors and differences between FE and FV solutions are greatly affected by the scheme used to compute the FV non-linear coefficients at the control volume surfaces. Simulations for rectangular channels show that FE yields smaller global errors then FV for velocity and temperature solutions

The fretting is responsible for many failures of components in the industry. It is present in assemblies like rivet and screw fixture, dovetailjoint, shaft and hub with key, and all connections of two bodies with a contact force and a small induced relative displacement. Topic of studies for decades, the researchers perform experimental tests with some simplification in order to accelerate the phenomenon, some times using standard devices or creating dedicated machines for better representing the behavior of the desired components. There are a few studies with thin sheets, in which the fretting fatigue has more impact because a small reduction of the cross section due to the wear of crack results in a significant increase of stress and rate of crack propatation, decresing the number of cycles until failure. In this work, it wasbuild a device to generate the fretting fatigue with two different shape of contact pad. The specimen is a stainless steel sheet thickness 0.152mm, which fractures and surfaces were analyzed using the SEM and white light interferometer to understand the fractures.