Abstract. A multimodal damping strategy is implemented by coupling a beam to its analogue electrical network. This network comes from the direct electromechanical analogy applied to a transverse lattice of point masses that represents the discrete model of a beam. The mechanical and electrical structures are connected together through an array of piezoelectric patches. A discrete and a semi-continuous model are proposed to describe the piezoelectric coupling. Both are based on the transfer matrix formulation and consider a finite number of patches. It is shown that a simple coupling condition gives a network that approximates the modal properties of the beam. A multimodal tuned mass effect is then obtained and a wide-band damping is introduced by choosing a suitable positioning for resistors in the network. The strategy and the models are experimentally validated by coupling a free-free beam to a completely passive network. A multimodal vibration reduction is observed, which proves the efficiency of the control solution and its potential in term of practical implementation.

The objective of this study is to develop the first fully passive nonlinear piezoelectric tuned vibration absorber (NPTVA). The NPTVA is designed to mitigate a specific resonance of a nonlinear host structure. To avoid the use of synthetic inductors which require external power, closed magnetic circuits in ferrite material realize the large inductance values required by vibration mitigation at low frequencies. The saturation of an additional passive inductor is then exploited to build the nonlinearity in the NPTVA. The performance of the proposed device is demonstrated both numerically and experimentally.This article is part of the theme issue 'Nonlinear energy transfer in dynamical and acoustical systems'.

Elastic lattice of point masses can be a suitable representation of a continuous rod for the study of longitudinal wave propagation. By extrapolating the classical tuned mass damping strategy, a multimodal tuned mass damper is introduced from the coupling of two lattices having the same modal properties. The aim of the study is then to implement this multimodal control on a rod coupled to an electrical network. The electromechanical analogy applied to a lattice gives the required network and the energy conversion is performed with piezoelectric patches. The coupled problem is modeled by a novel semicontinuous transfer matrix formulation, which is experimentally validated by a setup involving a rod equipped with 20 pairs of piezoelectric patches. The broadband efficiency of the multimodal control is also experimentally proved with vibration reductions up to 25 dB on the four first resonances of the rod. At last, the practical interest of the network is pointed out as it limits the required inductance. This is confirmed by the present purely passive setup that only involves standard low value inductors.

Multimodal damping can be achieved by coupling a mechanical structure to an electrical network exhibiting similar modal properties. Focusing on a plate, a new topology for such an electrical analogue is found from a finite difference approximation of the Kirchhoff-Love theory and the use of the direct electromechanical analogy. Discrete models based on element dynamic stiffness matrices are proposed to simulate square plate unit cells coupled to their electrical analogues through two-dimensional piezoelectric transducers. A setup made of a clamped plate covered with an array of piezoelectric patches is built in order to validate the control strategy and the numerical models. The analogous electrical network is implemented with passive components as inductors, transformers and the inherent capacitance of the piezoelectric patches. The effect of the piezoelectric coupling on the dynamics of the clamped plate is significant as it creates the equivalent of a multimodal tuned mass damping. An adequate tuning of the network then yields a broadband vibration reduction. In the end, the use of an analogous electrical network appears as an efficient solution for the multimodal control of a plate.

The resonant piezoelectric shunt requires specific inductance and resistance values in order to reach an optimum in terms of vibration reduction. Yet, practical limits appear in the low frequency range: the required inductance and the corresponding quality factor are often too high to be satisfied with standard passive components. In this paper, inductors are designed with closed magnetic cores made of high permeability materials. Those components are successively integrated into a piezoelectric shunt dedicated to vibration control of a cantilever beam. It is shown that custom designs can definitely extend the application of passive resonant shunt strategies to lower frequency.

Several solutions for multimodal vibration damping of thin mechanical structures based on piezoelectric coupling have been developed over the years. Among them, piezoelectric network damping consists in using piezoelectric transducers to couple a structure to an electrical network, where the transferred electrical energy can be dissipated. In particular, the effectiveness of coupling rods, beams and plates to their analogous electrical networks has been proven. This work is the first step going towards more complex structures. After defining and experimentally validating a fully passive electrical analogous network of a simply-supported plate, the study is extended to the damping of a non-periodic plate. The non-periodicities here studied include the addition of a local mass and a variable thickness. Numerical simulations and experiments show that in these cases, a broadband damping is achieved once the piezoelectric transducers are coupled to an adequate analogous network. A finite element model of the structure coupled to a 2D non-periodic electrical network is concurrently developed and validated, which is another contribution of the present work.

In this paper, the method of electric analog synthesis is applied to design a piezo-electro-mechanical arch able to show the capacity of multimodal damping. An electric-analog circuit is designed by using a finite number of lumped elements representing the equivalent of a curved beam. Spatial and frequency coherence conditions are proven to be verified for the modes to be damped: in fact, lumped-element circuit can damp only a finite number of vibration modes. Analogous boundary conditions are ensured, so that natural frequencies and mode shapes of both the curved beam and the analog circuit are equal. The instance considered here is the vibration mitigation of a piezo-electro-mechanical arch. Having a view towards prototypical applications, all simulations consider values of physically feasible passive circuital elements. It is believed that the present results may represent a step towards the design of multi-physics metamaterials based on micro-structures exploiting the principle of multimodal damping.

Vibrations of a mechanical structure can be reduced through a piezoelectric coupling to a passive electrical network exhibiting similar modal properties. For the control of a plate, the design of a two-dimensional analogous electrical network is considered. Depending on the mechanical boundary conditions, a finite difference formulation of the Kirchhoff-Love equation of motion shows that we need to ensure specific electrical connections along the edges of the analogous network. A numerical model involving an assembly of element matrices validates the electrical topology. Then, the passive electrical circuit is implemented with capacitors, inductors and transformers, whose practical design is closely described. Focusing on the analogue of a clamped plate, experiments prove the ability of the proposed electrical network to approximate the behavior of the mechanical structure.