COMPDYN 2017 6 th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering M. Papadrakakis, M. Fragiadakis (eds.) Rhodes Island, Greece, 15–17 June 2017 ENERGY HARVESTING IN A NONLINEAR SYSTEM UNDER HARMONIC AND RANDOM EXCITATIONS Tiago L. Pereira 1 , Aline S. De Paula 1 , Adriano T. Fabro 1 , Marcelo A. Savi 2 1 Universidade de Brasília, Department of Mechanical Engineering 70.910.900 – Brasília – DF, Brazil e-mail: tiagolei.tl@gmail.com, alinedepaula@unb.br, fabro@unb.br 2 Universidade Federal do Rio de Janeiro, COPPE , Department of Mechanical Engineering 21.941.972 – Rio de Janeiro – RJ, Brazil, P.O. Box 68.503 savi@ufrj.br Keywords: Piezoelectric, nonlinear system, energy harvesting, random excitation Abstract. Smart material has the ability to convert energy between two distinct physical do- mains. Piezoelectric material are an example of this material, the vibration-based energy har- vesting using piezoelectric elements is possible by exploring the direct effect, where the piezoelectric material is able to convert mechanical in to electrical energy. This application can be very useful for applications in powering small electronic devices. The energy harvesting system presented in this work is a magnetoelastic structure that consists of a ferromagnetic cantilevered beam with two permanent magnets, one located in the free end of the beam and the other at a vertical distance d from the beam free end. In order to use this device as a piezelectric power generator, two piezoceramic layers are attached to the root of the cantilever and a bimorph generator is obtained. The piezomagnetoelastic structure is subjected to a com- bination of harmonic and random excitations. The parameter Noise-to-Signal Ratio (NSR) is used in order to quantify different combinations of the forcing terms. A method to evaluate the harvested energy and the performance of the piezomagnetoelastic structure is proposed. The method is applicable both to deterministic and to non-deterministic signals and is based on the Power Spectral Density (PSD) of the input, dimensionless force, and the output signal, dimen- sionless electrical voltage. Numerical simulations are carried out identifying better combina- tions of harmonic and random excitations for energy harvesting purposes. Available online at www.eccomasproceedia.org Eccomas Proceedia COMPDYN (2017) 459-469 © 2017 The Authors. Published by Eccomas Proceedia. Peer-review under responsibility of the organizing committee of COMPDYN 2017. doi: 10.7712/120117.5432.17603