Análise do comportamento à fratura de elementos de concreto armado utilizando o LDEM-DYNA

Abstract

The existence of reinforced concrete depends directly on the joint behaviour of concrete and steel in reaction to stresses, which is generated by adherence. This property is responsible for the transfer of stresses and, consequently, the formation of cracks in the material. Cracks in concrete, in turn, act as entry routes for deleterious external agents, jeopardising the durability of structural elements and should therefore be avoided. This highlights the importance of studying adherence, stress transfer and crack formation in elements made from this structural material. In general, experimental analyses require a large number of tests with high control of the test conditions. Numerical analyses can be allied to these studies, as they allow research to be carried out at lower cost and in less time. In this context, in this work, reinforced concrete elements are analysed in terms of adherence, stress transfer and crack formation using hybrid models, in the ANSYS LS-DYNA software, from the combination of the Finite Element Method (FEM) with the Lattice Discrete Element Method (LDEM), called LDEM-DYNA. These models are validated using three experimental tests: tension stiffening test (tie rods), pull-out test and Stuttgart shear test. The results of the numerical models for the tension stiffening test were satisfactory with regard to the formation and development of cracks and global behaviour (stress-strain). In the pull-out test, both the global behavior and the rupture configuration were divergent from the experimental results. In the Stuttgart shear test, the global behaviour and fracture patterns of the beams were in good agreement with the experimental and other numerical data available in the literature. Therefore, hybrid models are a promising tool for analysing reinforced concrete elements. Keywords: Reinforced concrete. Adherence. ANSYS LS-DYNA. LDEM-DYNA.