Speaker
Description
Systems with more than one equilibrium belong to a group of nonlinear multi-stable structures. The multi-stability can be created by specific devices, for example by a system producing nonlinear magnetic force and enabling to obtain the potential function with two or more potential minima (potential wells). Another option is to add axial force to the structure which shifts the vibrating system to a buckling point with existing two equilibria (two potential wells). The composite technology offers new possibilities to create multi-stable structures by a proper selection of the geometry and material properties.
In this paper, we propose a specific shell design considered in two configurations, called shell A and shell B. Geometry of the shell A is based on conical surface and unsymmetrical composite layers layout. Depending on the parameters it may exhibits mono or bi-stability. The shell, while excited periodically, may oscillates around a single potential well (in-well dynamics) or can move between two potential wells (cross-well dynamics) with a rapid jump, called snap-through, from one to another equilibrium [1]. Shell B is based on a pseudo-conical surface and has the same composite layers layout. Such created shell B exhibits five equilibria and very complex dynamics, in-well or cross-well oscillations with snap-through between two potential wells, or cross-well oscillations with a jump among more than two wells. The unique nonlinear properties of the shells are attractive for the design of efficient energy harvesters or for dedicated control techniques when the rapid change between equilibria is required. The main goal of this paper is to present the untypical nonlinear effects of multi-stable systems and their application to energy harvesting, morphing, and control [2].
Acknowledgment
This research was funded in part by National Science Centre, Poland 2021/41/B/ST8/03190.
References
[1] Mitura, A., Brunetti, M., Kloda, L., Romeo, F., Warminski, J.: Experimental nonlinear dynamic regimes for energy harvesting from cantilever bistable shells. Mechanical Systems and Signal Processing 206 (9), 110890, 2024
[2] Warminski J.: Nonlinear dynamics of self-, parametric, and externally excited oscillator with time delay: van der Pol versus Rayleigh models. Nonlinear Dynamics 99, 35-56, 2020.
