Hybrid microstructural finite element modeling for intergranular fracture in ceramic composites and coated systems

In this work, the mechanical behavior of ceramic composites and ceramic coatings has been investigated through a non linear micromechanical hybrid finite element approach. The Voronoi cell finite element method (VCFEM) has been extended in order to investigate the damage tolerant behavior at the microstructural length scale in homogeneous ceramics, Alumina/Zirconia composites and ceramic coatings on metal substrate. ing Griffith’s energy-balance method a criterion based on the average normal tensile stress acting on the grain boundary has been assumed as condition for the nucleation and propagation of intergranular fractures. The presented finite element formulation has been implemented into a commercial displacement-based finite element code. per presents the study of the effects of the residual stresses and gradient mechanical properties on the near-surface stress field arising in contact problems, considering the intergranular fracture nucleation and propagation phenomena. Relevant fracture patterns are obtained allowing comparisons between the performances of different gradient ceramic structures. Moreover the microstructural cracking of hard ceramic coatings on elastic-plastic substrates has been simulated.