Single-degree-of-freedom energy harvesters by stochastic excitation

• Main Author: Joo, Han Kyul
• Other Authors: Themistoklis P. Sapsis.
• Format: Others
• Language: English
• Published: Massachusetts Institute of Technology 2014
• Subjects: Mechanical Engineering.
• Online Access: http://hdl.handle.net/1721.1/92138

Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014. === Cataloged from PDF version of thesis. === Includes bibliographical references (pages 97-100). === In this thesis, the performance criteria for the objective comparison of different classes of single-degree-of-freedom oscillators under stochastic excitation are developed. For each family of oscillators, these objective criteria take into account the maximum possible energy harvested for a given response level, which is a quantity that is directly connected to the size of the harvesting configuration. We prove that the derived criteria are invariant with respect to magnitude or temporal rescaling of the input spectrum and they depend only on the relative distribution of energy across different harmonics of the excitation. We then compare three different classes of linear and nonlinear oscillators and using stochastic analysis tools we illustrate that in all cases of excitation spectra (monochromatic, broadband, white-noise) the optimal performance of all designs cannot exceed the performance of the linear design. Subsequently, we study the robustness of this optimal performance to small perturbations of the input spectrum and illustrate the advantages of nonlinear designs relative to linear ones. === by Han Kyul Joo. === S.M.