Exploring and exploiting complex nonlinear dynamical states in friction-excited mechanical systems

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FIV represent a major problem in different industrial applications, from the automotive to the aerospace engineering. Despite the great effort that has been invested in the recent years FIV are still defined "random", "low repeatable", "capricious". The recent advances in numerical and theoretical modelling of FIV show that friction affected dynamical systems may experience a multitude of dynamical states, in particular spatially localized vibrating states, stick-slip/full-slip propagating fronts and stick-slip pulses. The role that those transitory states play in the development of FIV has been often neglected in the literature, which, instead, has focused mostly on the stationary, global behaviour of frictional systems. We propose to study in detail the phenomenon of spatial localization of FIV and their propagation at the interface as stick-slip fronts or pulses. The experimental observed “randomness”, in fact, may be caused by our lack of understanding of how frictional systems evolve during the transients through different transitory states. We will focus on friction-excited discrete regular structures. The first two objectives and workpackages aim at studying and characterizing the localized and the propagating states in terms of region of existence, stability, velocity of propagation, sensitivity to system parameters and to the friction law. The third objective and corresponding workpackage aim at exploiting the observed nonlinear states. We will focus on the possibility of selecting the proper dynamical state to obtain the desired friction coefficient and dissipative behaviour. This "first-time" proposal is for the applicant a unique opportunity to start a more independent research and broaden his knowledge in friction-excited dynamical systems working in the Dynamics Group at TUHH. His background in contact mechanics and non-linear dynamics will be of crucial importance to face this challenging project.