Characterization of Fatigue in Integrated Tuned Mass-Dampers

Abstract

Recent work concerned with passive vibration suppression in structural systems has focused on the development of metastructures. Metastructures (also called architected materials) are a type of mechanical metamaterial: an object arranged or constructed in such a manner that it has traits unachievable by its constituent material. Metastructures often consist of embedded spring mass systems made from small beams with a tip mass or chiral lattice structures with mass inserts. The goal of a metastructures design is to reduce vibrations of the host structure. It does this using the absorber action of the embedded spring mass systems. The embedded tuned mass dampers (TMDs) then become prone to sustaining failure by fatigue. While many recent papers discuss various geometric and material designs, very few if any address the issues of fatigue of the embedded absorbers. This paper makes an initial investigation into the relationship between the TMDs’ geometric parameters and their fatigue performance with the goal of improving the design and implementation metastructures. A sensitivity analysis was performed to identify the geometric TMD parameter with the largest impact on natural frequency and stress concentration. Analytical models for natural frequency and maximum stress were developed for the TMDs and compared to finite element models. The analytical models were substantiated by the FEA models for some of the perturbed parameters, indicating that further work would be needed to confirm that, for a given parameter, a certain trend in natural frequency indicates an anticipatable trend in stress.