Evaluation of the mechanical behavior of concrete wall panels with functionally gradation fiber content by finite element method

Resumo

Concrete is a material with brittle rupture behavior when subjected to efforts that result in tensile
stresses, generating internal micro-cracks, facilitating the action of aggressive agents and reducing its useful life.
With the demands of improving the durability and mechanical performance of structures, the functional gradation
of concrete properties with the use of fibers has been presented as a promising alternative. With the recent
publication of NBR 16935, in addition to contributing to durability, fibers can be used to totally or partially replace
steel reinforcement, especially in structural elements where the distribution of internal tensile stresses is not well
defined, as in the case of of wall panels and other slender pieces subjected to compression. The production of
concrete wall panels with functionally gradation of fiber content allows a more efficient use of materials,
distributing the fibers only in the regions that can present a real contribution, enhancing their physical and
mechanical properties due to their presence. This work seeks to evaluate the mechanical behavior of functionally
graded fiber concrete wall panels through modeling and computer simulation. The model was implemented in the
commercial software ANSYS, which is based on the finite element method. Different configurations of the
functional gradation of the fibers were simulated along the thickness and in different regions. Each configuration
of the functional gradation in the panels were simulated in static and buckling analyses. For calibration of the
parameters of the materials of each layer, the values present in the literature for different types and fiber contents
were adopted. Finally, the numerical results obtained were compared with experimental results from the literature
to validate the proposed model. The functional gradation of fiber content did not compromise the strength of the
panels and the model adopted presented an acceptable correspondence with the experimental results found in the
literature.