NONLINEAR CYCLIC ANALYSIS WITH UNLOADING-RELOADING LAWS BASED ON MOVING FOCAL POINT

Resumo

Constitutive models are mechanical-mathematical formulations that describe the behavior
of a material. For a complete representation of the medium, these models must be able to reproduce
the processes of loading, unloading and reloading. Usually, models for quasi-brittle materials present
deterioration of the elastic modulus, while residual strains are not verified. Models for ductile materials,
although, have their elastic modulus preserved during unloading and that results in permanent strains. In
real materials analysis what is observed is a composition of these two behaviors. The literature presents
analytical models to incorporate both hypotheses, developed from the concept of focal point. Traditional
formulations usually work with a fixed focal point. Thus, in order to expand existing formulations,
this work presents an elastic degradation model associated with cyclic stress-strain laws according to a
moving focal point, which varies depending on the deterioration of the material medium.