Numerical analysis of a smeared cracking model for concrete structures

Resumo

Analytical models for concrete often become ineffective or difficult to parameterize due to its highly
complex and heterogeneous microstructure, as well as its physically non-linear behavior. This fact justifies the use
of numerical methods, such as the Finite Element Method, for modeling the mechanical behavior of the material
more realistically. One of the main phenomena responsible for the physical nonlinearity of concrete is cracking,
which occurs even at low loading levels, due to its low tensile strength when compared to the compressive one.
In this context, the present work aims to study cracked concrete structures using a smeared cracking model based
on monitoring the deterioration of the material’s physical properties. The Finite Element model was implemented
using an isoparametric element for plane elasticity. The cracking process is described by the decay of stresses with
increased strains, through different stress-strain relationships extracted from the literature that represents the overall
behavior of concrete in tension or compression. A cracking model based on the inversion of compliance with a
local secant constitutive matrix was used, which takes into account the undamaged secant Young’s modulus of the
material. This nonlinear model has been implemented using the MatLab platform with a generalized displacement
control sover. The results for different combinations of stress-strain curves were compared and the method was
validated through comparison with the ones of other authors.