Title: Identification of viscous and structural damping in the dynamic system

Authors: Vikas Arora

Addresses: Institute of Technology and Innovation, University of Southern Denmark, Campusvej 55, Odense 5230, Denmark

Abstract: Damping still remains one of the least well-understood aspects of general vibration analysis. In this paper, a new experimental damping identification method, which can be able to identify both viscous and structural damping in the dynamic system, is proposed. The proposed method is a direct method and gives explicit structural and viscous damping matrices. The proposed method requires prior knowledge of accurate mass and stiffness matrices. So, experimental viscous-structural damping is identified in two steps. In the first step, mass and stiffness matrices are updated and subsequently viscous and structural damping matrices are identified using updated mass and stiffness matrices obtained in Step 1. The identified viscous-structural damping matrices are both symmetric and positive definite. The effectiveness of the proposed structural damping identification method is demonstrated by numerical and experimental examples. First, two numerical study of lumped mass system and fixed-fixed beam are presented which is followed by an experimental example of cantilever beam. The effects of coordinate incompleteness and different level of damping are investigated. The results have shown that the proposed method is able to identify accurately both viscous and structural damping in the dynamic system.

Keywords: finite element model updating; damping identification; dynamic system; direct method; viscous-structural damping.

DOI: 10.1504/IJSTRUCTE.2017.089396

International Journal of Structural Engineering, 2017 Vol.8 No.4, pp.345 - 360

Available online: 17 Jan 2018 *

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