1,721,109 research outputs found
Modelling of micromechanical fracture for ceramic composites through the Voronoi Cell Finite Element approach.
No full textIn this work the micromechanical behaviour of ceramic composites has been investigated through a non-linear hybrid finite element approach. The Voronoi Cell Finite Element Method has been extended in order to investigate the damage tolerant behaviour at the microstructural length scale in homogeneous ceramics and Alumina/Zirconia composites. A criterion based on the average normal tensile stress acting on grain boundary has been assumed as the condition for the nucleation and propagation of intergranular fractures. The paper presents the study of the effects of the residual stresses and gradient mechanical properties on the near-surface stress field arising in contact problems
A Voronoi cell finite element model for the indentation of graded ceramic composites
No full textThis paper presents a numerical approach, based on the Voronoi Cell hybrid Finite Element formulation, to the evaluation of the
mechanical properties of Alumina/Zirconia graded composites.
The computational model is based on two main features: (i) the discretization of the domain into homogeneous regions having
geometrical features similar to those of the grains in each phase and (ii) the formulation of hybrid finite elements having polygonal
shape and a non linear constitutive formulation which takes into account permanent strains and thermal effects. The purpose of the
computational tool is to study the mechanical behaviour of layered graded materials subjected to contact loads on the surface.
The analyses have shown that a stress redistribution and a lowering of the maximum tensile stress can be obtained by introducing a
proper gradient of the mechanical properties of the ceramic composite. The results have shown that the effects of the thermal residual
stress field, induced by the manufacturing process, must be taken into account for a proper assessment of the mechanical behaviour of
the graded ceramic composites
The Voronoi cell finite element method for mechanical characterization of graded ceramic coatings on artificial joints
No full textDetermination of the effective elastic–plastic response of metal–ceramic composites
No full textThe mechanical response of metal–ceramic composites is analysed through a homogenization
model accounting for the mechanical behaviour of the constituent materials. In order to achieve this
purpose a nonlinear homogenization method based on the phase field approach has been suitably
implemented into a numerical code. A prescribed homogenized strain state is applied to a unit volume
element of a metal–ceramic composite with proportional loading in which all components of the
strain tensor are proportional to one scalar parameter. The mechanical response of the material has
been modeled by considering a von Mises plasticity model for the metal phase and a Drucker–Prager
associative elastic–plastic material model for the ceramic phase. A two stages plasticity has been
obtained in which inelastic strain develops in the metal phase followed by a fully plastic response.
A comparison with a finite element model of the stress–strain response of an axisymmetric unit cell
has been carried out with the purpose to validate the homogenization based modeling presented in
the paper. Plastic parameters of a Drucker–Prager yield surface for the homogenized composite have
been calculated at different materials compositions. Associative Drucker–Prager plasticity has been
found to be accurate for high ceramic content
Hybrid microstructural finite element modeling for intergranular fracture in ceramic composites and coating systems.
No full textProprietà meccaniche di compositi ceramici a gradiente funzionale per applicazioni biomediche: un approccio computazionale
No full textPredicting fatigue life of a PMMA based knee spacer using a multiaxial fatigue criterion
No full textAssessment of the biomechanical compatibility of an interspinous implant for dynamic stabilization through the finite elment method
No full textFunctionally graded coatings for wear resistant biomedical devices: experimental measurements and modeling of nanoindentation tests
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