Modelagem númerica de aumento de tenacidade a fratura de materiais de base frágil reforçados por fibras

Abstract

Advanced ceramic material are of great technological interest because of their intrinsic mechanical and physical properties such as low density , high corrosion resistance and abrasion resistance , low thermal conductivity , high temperature resistance , wear and compression . However, a major limitation in the implementation of structural ceramics with predominantly nature of ionic bonds, due to the high fragility of their headquarters. Complete characterization of high performance composites produced by addition of fiber needs to determine the relationship among approximately thirteen parameters such as fiber dimensions, strength, elastic modulus, fiber volume percentage, fracture resistance and coefficient of friction on the fiber / matrix interface. To clear the interaction of those parameters, experimental methods is highly expensive both in the cost and execution time. Therefore, mathematical modeling is essential in the design of these materials. This work presents a numerical model for analysis of fiber reinforced cementitious composite using ANSYS which is based on the finite element method. The theoretical model proposed for the concrete constitutive model is based on the theories of elasticity and fracture mechanics in order to give a numerical treatment best suited for estimation of the toughening in composite materials reinforced with fibers. The language of ANSYS Parametric Design Language (APDL) will be adopted with the objective of geometric model creation and process optimization . The results will be compared with ones of numerical models and experiments, extracted from papers presented by other researchers. The comparisons of results show the importance of spalling effect, fiber elasticity module , process of fiber/matrix interface debonding and fiber pull-out from the matrix. The results confirm that there is an optimum combination of the parameters that can significantly increase in fracture toughness of the composite.