Avaliação numérica dos parâmetros que influenciam o comportamento pós-fissuração do CRFA utilizando uma abordagem multiescala

Abstract

Nowadays, several computational models with a multiscale approach have been proposed to predict the mechanical behavior of steel fiber reinforced concrete (SFRC). These models have presented promising results, since they can be used to evaluate the influence of the different phases of the composite (matrix, fibers and fiber-matrix interaction) on the mechanical behavior of the material and, consequently, support the interpretation of the variability of responses usually found in laboratory tests. In addition, these models are very useful in obtaining performance parameters (post-cracking) to be used in the design of structural members, since, unlike conventional concrete characterization tests, the tests for this type of composite are more complex and require a greater amount of materials. However, the feasibility of applying these models has been performed with the adoption of several simplifying hypotheses that need to be better understood in order to increase the reliability of the results obtained. In this sense, this research project aims to evaluate the main variables of the multiscale model proposed by Bitencourt Jr. et al. (2019) that influence the obtaining of SFRC post-cracking parameters, such as: the model employed for the generation and distribution of a cloud of steel fibers (uniform and non-uniform); the laws adopted to represent the fiber-matrix interaction; the representability of the responses obtained from the simulation using 2D models; and the technique adopted to represent the process of formation and propagation of cracks (continuous vs. discrete models). The study will be developed within the scope of the FAPESP Research Project (No. 2019 / 24487-2) entitled "Design of beams aided by a multiescale model" and, consequently, will have as main focus, the application of the methodology proposed in the simulation of the three-point bending test, as recommended by EN14651, and the Dews test.It is expected at the end of this research to obtain a better understanding about the variables that influence the SFRC post-cracking parameters using multiscale approach and, consequently, a numerical tool capable of simulating SFRC characterization tests with the confidence necessary to obtain performance parameters to design safe and economical structural members.