Stochastic quantification of the duration of the stick mode of a simple dry-friction oscillator with a random friction coefficient

Roberta Lima¹; Rubens Sampaio¹

¹ PUC-Rio

doi:10.20906/CPS/COB-2015-0564

Resumo

This paper investigates the dynamics of a simple dry-friction oscillator which is composed by a block, modeled as a particle, connected to a fixed support by a spring. The block moves over a continuous belt that is driven by rollers. Between the block and the belt there is a frictional force modeled as a Coulomb friction. This friction induces in the system self-sustained oscillations, which are characterized in two qualitatively different modes (stick and slip) with a non-smooth transition. The focus of the paper is to determine from a deterministic and from a stochastic viewpoint the duration of the stick mode in the system response considering different models to the friction coefficient which is not constant along the belt length. Virtual experiments are performed assuming that the friction coefficient varies harmonically along the belt length and also varies in a discontinuous way. In the stochastic analysis, friction coefficient is modeled as a random field. The objective is to determine what are parameters of these models of non constant friction coefficient that control the stick duration.

Palavras-chave: friction-induced vibration; stick-slip; non-smooth system; nonlinear-dynamics; stochastic modeling; uncertainty quantification