Modelling of elastic properties of sintered porous materials

Abstract

Models for prediction of the elastic characteristics of natural and synthetic porous materials are reexamined and new models are introduced. First, the Vavakin-Salganik (VS) model for materials with isolated spherical pores is extended in order to take into account various statistical distributions of pore sizes. It is shown that the predictions of the extended VS model are in good agreement with experimental data for porous materials with isolated pores such as foamed titanium, porous glass and sandstone. However, the model is in a considerable disagreement with the experimental data for materials sintered from metal powders. The disagreement is explained by the presence of merged and open pores whose shapes cannot be well approximated as spheres. Using the theory of geometrical probabilities, the amount of pores that are close enough to overlap is estimated, and a model is introduced where merging pores are modelled as corresponding ellipsoids. Another modification is proposed to take into account open pores. This modification is based on the classical Rabotnov-Kachanov approach to damage accumulation in the loaded material. Finally, predictions given by the above models, and their combination is compared with experiments. A good agreement is observed between the combined model and the available experimental data for a variety of sintered materials.

Influence of the Total Porosity on the Properties of Sintered Materials—A Review

“…However, a refined model should also include microstructural parameters, such as the shape and size of the pores and maybe of the initial powder particles. Many attempts have been made in this direction [4][5][6][7][8][9][10][11]. Unfortunately, the variability of the morphological and dimensional characteristics of the porosity, together with the non-negligible effects of both the impurities usually present in commercial powders, and of the variable quality of the junctions between the powder particles, limits the applicability of the theoretical models.…”

Microstructure and Mechanical Properties of Fe/MgO Micro-Nano Composite for Electrotechnical Applications

“…Decreasing Young`s modulus in dependence on MgO content indicates increasing porosity values. Porosity has stronger influence on elastic properties than increasing content of MgO ceramic phase as it was calculated by Manoylov et al[7].…”

Tensile strength of granular aggregates: Stress chains across particle phase versus stress concentration by pores

“…Granular aggregates partially filled with a binding matrix belong to this broad class of structured porous materials. It includes concrete [3,4], sintered powders [5,6], sedimentary rocks [7], and wheat endosperm (composed of starch granules distributed in a protein matrix) [8]. Understanding the origins of their elastic and failure properties is of practical interest for the design of concretes [9][10][11][12][13], dense particle-filled composites [14], and other new materials [15][16][17], as well as for predicting rock fracture [18,19] and the influence of operating parameters on cereal milling [8,20].…”