A modified Ehlers model for the description of inelastic behavior of porous structures

TL;DR

This paper introduces a modified Ehlers model tailored for porous media, enhancing the description of inelastic behavior by adjusting the yield potential to account for hydrostatic stress effects.

Contribution

It presents a novel modification to Ehlers' model that accurately captures the inelastic response of porous structures within a general isotropic plasticity framework.

Findings

Model accurately predicts inelastic behavior of porous media.

Calibration aligns model with finite element simulation data.

Modified yield surface improves stress state representation.

Abstract

This paper describes a modification of Ehlers' model for the inelastic behavior of granular media. The modified model can be applied for describing the inelastic behavior of porous media. The key feature is a subtle change of the yield potential, which allows the correct orientation of the triangular-shaped yield surface cross sections depending on the hydrostatic stress state. The model is incorporated into a general framework for isotropic plasticity. An elastic predictor/corrector algorithm is employed to solve the constitutive equations. The necessary derivatives for a Newton update are also given in detail. The model is calibrated using stress, and strain data obtained from finite element simulations of a generic highly porous open-cell Wheire-Phelan foam.