Computational implementation of constitutive models of mortar joints for the analysis of masonry panels in ANSYS

Resumo

The modeling of a masonry panel may be a complex task due to the anisotropic behavior of the
composite material. Deformation and failure properties depend on both the stress orientation and the joint
direction, since the mortar-unit interfaces act as weak surfaces. The simplified micro-modeling approach is one of
the several strategies that have been proposed for the numerical analysis of masonry panels in the frame of the
Finite Element Method. This approach makes use of zero-thickness interface elements to represent mortar joints
and simulate their sliding and opening behavior with appropriate constitutive models. This work analyzes the
behavior of structural masonry panels by using the simplified micro-modeling approach with the application of
the Finite Element Method software ANSYS. Two plasticity constitutive models for the mortar joints could be
investigated: a Mohr Coulomb envelop with tension cut-off and compressive cap with hardening, and a Mohr
Coulomb envelop with tension cut-off and bilinear damage. The corresponding algorithms were implemented into
an ANSYS user material subroutine by employing an implicit scheme using the return mapping algorithm.
Numerical results were compared to some experimental results available in literature.