Modelo computacional do aumento da tenacidade do concreto de reforço por fibras utilizando ANSYS

Abstract

This work present a computational model for analysis of fiber reinforced cementitious composite using ANSYS which is based on the finite element method. The modeling is focus on simulating a single fiber pullout inserted into the concrete matrix and analyzing the individual contribution of each fiber to the ultimate strength and toughening of the composite. Through a computational procedure united ANSYS and MATLAB it is possible to connect the finite elements model to mathematical model. By use of the cohesive zones model (CZM) and ԏ (s) relationship, the friction on the interface is simulated and the interfacial performance as well as the pressure distribution at the interface are analyzed. The results of bridging force versus crack opening are compared with experimental tests obtained in the literature for different types of fibers embedded into cement matrix with different angles of inclination relative to the fractured surface. Using the William-Warnke failure surface for the concrete, the spalling in the matrix is quantified. To understand how the spalling is formed and propagated the pressure distribution on the interface that still little studied is analyzed. The results show that there are optimun parameters that could significantly improve the strength and toughness of composites. Both spalling and the pressure distribution on the interface show why the mechanical properties of fiber, matrix and interface and geometry of the fiber, favor or not the improvement in mechanical strength and toughness of the composite.