Parametric study of combined tensile and shear-frictional damage models on the simulation of mesoscopic compressive failure in concrete

Resumo

One approach that provides a more realistic numerical prediction of concretes mechanical behavior is the use of a mesoscopic scale, considering the different phases of the composite. To represent the non-linear material behavior, appropriate constitutive models must be employed, such as non-linear elasticity, damage or plasticity, among others.
A Mesh Fragmentation Technique that places high aspect ratio interface elements between the regular mesh elements, delineating the potential crack paths, has been employed to model the complex crack propagation process in quasi-brittle materials such as concrete. Recently, an extension of this technique introducing a two-layer condensed interface element has been proposed. This two-layer element allows to describe compressive failure as a combination of debonding (mode-I) and sliding (mode-II) cracking, so that each layer is respectively ruled by tensile and shear-frictional constitutive damage models.
One advantage of the proposed model is that it requires a reduced number of material parameters: tensile strength, fracture energy, cohesion, friction angle and shear softening. A parametric study aiming to evaluate the role played by each one of the parameters on the mechanical behavior of concrete is presented. A series of mesoscale uniaxial compression tests is simulated and the obtained predictions are compared to the correspondent experimental results. The influence of each parameter is evaluated in terms of the resulting average stress-strain curve, as well as the qualitative aspect of the specimen failure, described by the cracking patterns. This parametric study contributes to determining which parameters are more influential in the combined material failure, providing insights for future structural members simulations using the proposed technique.