New Developments in Analytical Modeling of Mechanical Behavior of ECC

Abstract

Finite element method in conjunction with an appropriate material model may serve as a suitable tool to analyze the structural performance of Engineered Cementitious Composites (ECCs) - short fiber reinforced composites, which exhibit pseudo strain-hardening behavior and multiple cracking under tension. Several such models are reviewed and some new formulations are proposed. The new model represents a composite in multiple cracking state as an equivalent continuum with identical macromechanical properties. The constitutive law of the equivalent continuum is obtained as a relationship between overall stress and strain of a representative volume element (RVE). The RVE is modeled as a solid element intersected by fiber-bridged matrix cracks. In order to relate the relative displacements of crack faces to the bridging tractions, a generalized model of crack bridging is derived. A relationship between stress and crack density is also discussed. The resulting constitutive law is suitable for implementation in FEM, yet maintains a transparent link to a composite microstructure.