Random stick-slip oscillations in a multiphysics system

At LMSSC, Paris, July 7th 2023, 2 p.m.

Roberta de Queiroz Lima
Assistant professor, Department of Mechanical Engineering, Pontifícia Universidade Católica (PUC), Rio de Janeiro, Brazil

The presentation shows some of the work done in the last five years, and the interactions between these works. The stochastic response of a multiphysics system with stick-slip oscillations is analyzed. The system is composed of two interacting subsystems, a mechanical with Coulomb friction and an electromagnetic (a DC motor). An imposed source voltage in the DC motor stochastically excites the system. This excitation, combined with the dry-friction, induces in the mechanical subsystem stochastic stick-slip oscillations.

The resulting motion of the mechanical subsystem can be characterized by a random sequence of two qualitatively different and alternate modes, the stick- and slip-modes, with a non-smooth transition between them. The duration of each stick-mode is uncertain and depends on electromagnetic and mechanical parameters and variables, specially the position of the mechanical subsystem during the stick-mode. Duration and position are dependent random variables and must be jointly analyzed.

The objective of this work is to characterize and quantify this stochastic dependence, a novelty in the literature. The high amount of data required to perform the analysis and to construct joint histograms puts the problem into the class of big data problems.