The mechanical behaviour of the materials used as compressible gasket in the ultra high pressure apparatus is investigated. Materials such as pyrophyllite and talc, showing a pressure sensitive plastic flow behaviour were considered and a testing configuration was set up for studying the dependence of their plastic response on the hydrostatic component of the stress tensor, according to the Drucker-Prager criterion. A Finite Element modelling of the test was performed to evaluate the specimen response and the local stress condition, during loading. The Finite Element results were validated by comparison with those of a specific experimental characterisation. A parametric analysis was then carried out, by varying the materials constitutive behaviour, in order to build up a data base of representative curves. In this way an algorithm was developed, with the aim of determining the material constitutive behaviours by the analysis of the experimental data. The proposed procedure was then used to study the mechanical response of different gasket materials.

In the present work the performance of finite element formulations with different reduced integration strategies is evaluated for Contact Mechanics applications. One-point quadrature and selective reduced integration are utilized here using hourglass control to suppress volumetric and shear locking for materials with incompressible plastic behavior and bending-dominated problems. A corotational formulation is adopted to deal with physically and geometrically nonlinear analysis and the generalized-α method is employed for time integration in the nonlinear dynamic range. The contact formulation is based on the penalty method, where the classical Coulomb's law is used considering a convected coordinate system for three-dimensional friction with large deformation and finite sliding. Contact problems involving deformable and rigid bodies, as well as static and dynamic analysis, are investigated and results are analyzed considering the different underintegration formulations proposed here.

mantiveram certa resistência. Este comportamento pode estar associado pela menor área de exposição da argamassa nas juntas de assentamento, bem como efeito favorável do confinamento desta nas juntas.

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