MODELLING MR DAMPERS UNDER NON-HARMONIC EXCITATIONS THROUGH LOGISTIC CURVE MODELS

Resumo

The present work proposes modifications for a MR damper Sigmoid-curve-based mathematical model
in the literature to expand the range of conditions in which it can be employed, such as white noise excitations,
as well as increase its accuracy. The proposed formulation is compared to Bingham and Bouc-wen models, two

formulations with widespread use for MR dampers. The Sigmoid model addressed some issues with prior mod-
els, such as their inaccuracy in situations where the current or excitation were continuously varied. However, this

articles demonstrates that the model has stability issues, including instances of numerical divergence. This article
proposes tweaks that eliminate the issue. It also further proposes an expanded model with more parameters based

on the generalized logistic curve, evaluating if a better agreement between the numerical model and the experi-
mental data is possible. The results are compared according to the sum of the absolute difference between the

experimental and predicted force on steady-state conditions, where a lower value means a better agreement. The
new model decreased the disagreement between the theoretical and numerical models by 8,6%. The modifications
to address the numerical divergence were a success.