Numerical simulation of mesomechanical behavior of porous brittle materials

Abstract

The influence of the types of porous structure on the features of deformation, damage accumulation and fracture of mesovolumes of brittle materials is studied. At the mesoscale, the pores of different shape are taken into account explicitly. The digital models were made using random values of coordinates and radii of spherical voids or solid spheres. For numerical modeling of the mechanical behavior up to failure, the evolutionary approach is applied with considering the nonlinear constitutive equations to describe damage accumulation and its influence on the degradation of the strength properties of the frame of porous ceramics. The calculated averaged stress-strain diagrams were shown to be sensitive not only to the value of porosity but also to the shape of pores. The simulation results are validated with experimental data for zirconia and alumina ceramics. Good qualitative and quantitative agreement of modeling results with experimental data suggests that taking into account of two-scale porosity in the form of explicit consideration of large pores at the mesoscale and implicit integrated consideration of tiny pores and cracks from the microscale in the form of accumulated damage is quite sufficient in the framework of the hierarchical modeling.