ANALYSIS OF LOCAL TENSILE RUPTURE INFLUENCING SHEAR STRENGTH ON UNIAXIAL TEST MODELLING

Resumo

Constitutive models are mathematical formulations capable of describing the macroscopic
behaviour of an ideal medium. These models result from the application of simplifying hypotheses
about the behaviour of the real environment. Therefore, the selection of the constitutive model to be
used must be related to the problem to be solved, since it would not be trivial to obtain a single
formulation that would allow reaching the general solution for the material behaviour. In this sense,
modelling is a feature that describes the behaviour of materials subjected to real stress states, such as
uniaxial tests performed in the laboratory. Modelling of this type of test is generally performed

through models that describe the shear behaviour of the sample, such as Mohr Coulomb and Drucker-
Prager models. However, when observing some experiments in the laboratory, it was verified that

there are local tensile zones in the samples, which allows a reduction of the material resistance. In this
sense, this article presents a study of a rock sample that was submitted to the Uniaxial laboratory test
and its resistance was reduced by the tensile zones. Furthermore, in this work the numerical modelling
of this test will be presented and the impact of considering these zones of damage in the sample, the
constitutive model adopted in these simulations was the tensile damage.