Modelos para a descrição da heterogeneidade de meios parcialmente frágeis

Abstract

Quasi brittle materials that are frequently used in engineering describe in a numerical model as homogenous. Although, this material is made by phases, that has different characteristics and mechanical behaviors, between its self and when in interaction becoming a single material this phase made material shows a very complex and strongly nonlinear behavior. Concrete is one of this material, and may be described as a material made by three phases: mortar, aggregates and the interface between both. Because of its composition, its very difficult to define concrete s mechanical properties, its damage process and its fracture behavior, that are very complex. That s why a suitable description of this material, by introducing its intrinsic heterogeneity, is very important. The medium heterogeneity may be realized with an indirect approach by probabilistic models or with a direct approach that is made with the placement of particles that symbolizes the material heterogeneity. This work aims to analyse both approaches of heterogeneity introduction in computational modelling of quasi brittle materials.As an example of indirect approach this work uses the random assembler of phases in the integration points of the finite elements. While in a direct approach, the placement of a particle grid in the domain derivates in a phase geometrical placed domain. Both approaches were implemented in INSANE (INteractive Structural ANalysis Environment).