A Virtual Testing Strategy to Determine Macroscopic Properties of Elasto-Plastic Heterogeneous Composite Materials

The objective of this work is to determine an e˙ective yield criteria for porous pressure sensitive solids and investigate the anisotropic yield behavior by employing a virtual testing strategy. The work is concerned with the pressure sensitivity typically displayed by geometarials, such as sandstone and composite materials consisting of a series of parallel layers, such as sedimentary rock and underground salt.Virtual testing strategy is based on computational homogenization approach for the definition of the elasto-plastic transition. Representative volume elements (RVEs) containing single-centered and distributed ellipsoidal voids are analyzed using three-dimensional finite element models under both small and finite strains. Yield curves are obtained following a unified variational formulation, which provides bounds on the e˙ective material properties for a given choice of the Representative Volume Element (RVE).In order to estimate the e˙ective properties of porous solid, the constitutive behavior of the continuum matrix is assumed to follow the standard Drucker-Prager elasto-plastic model. The computationally generated e˙ective yield criteria are compared against the recently proposed analytical estimates for Drucker-Prager type solids and the SR4 constitutive model for soft rocks. The developed computational approach is applied to estimate the e˙ective properties of a realistic rock sample. To illustrate a wide range of potential engineering applications, the computationally e˙ective yield surface are also obtained under the explicit finite element method.Finally, based on the simulated yield stress point of composite materials, the pa-rameters for proposed analytical models are acquired with ellipse fit by Taubin’s method.