Localization Predictions Of The Micropolar Microplane Theory.

Abstract

The micropolar microplane theory by Etse, Nieto and Steinmann (2002) [14] is based on
a reformulation of the classical Cosserat theory within the framework of the microplane
concept. The resulting constitutive equations and models include available and more precise
information of the complex microstructure of engineering materials like concrete and
other composites as compared with the classical smeared crack-based material theories.
The main aim of this enriched material formulation was the macroscopic modeling and
description of anisotropic material response behaviors by means of the well-developed microplane
concept applied within a micropolar continuum setting. To derive the micropolar
microplane theory a thermodynamically consistent approach was considered whereby the
main assumption was the integral relation between the macroscopic and the microscopic
free energy as advocated by Carol, Jirasek and Bazant (2001) [10] and Kuhl, Steinmann
and Carol (2001) [15]. In this approach the microplane laws were chosen such that the
macroscopic Clausius-Duhem inequality was fully satisfied. This theoretical framework
was considered to derive both elastic and elastoplastic micropolar microplane models.
After refreshing the most relevant equations of the micropolar microplane theory, this paper
focuses on the evaluation of the localization predictions of this constitutive formulation.
A comparative analysis with the predictions of the classical micropolar constitutive theory
is also included.