Title: Element damage assessment in semi rigid connected structures using modal domain data

Authors: Bharadwaj Nanda; Damodar Maity; Dipak Kumar Maiti

Addresses: Department of Civil Engineering, Veer Surendra Sai University of Technology, Burla, Odisha, 768018, India ' Department of Civil Engineering, Indian Institute of Technology, Kharagpur, West Bengal, 721302, India ' Department of Aerospace Engineering, Indian Institute of Technology, Kharagpur, West Bengal, 721302, India

Abstract: Current vibration-based damage assessment techniques assumes that the joints in a structure behave either perfectly rigid or perfectly flexible. However, joints in the bolted structures are semi-rigid, which means the elements may show rotations to a certain degree on the basis of a fixity factor. In this regard, the present work proposes an alternate solution to conventional inverse damage identification problems by providing due weightage to the joint rigidity. The beam-column joints for this study are made semi-rigid by reducing their end fixity factor. An inverse problem is formulated here using changes in the natural frequencies and mode shape vectors caused due to damages, which is then solved by a unified particle swarm optimisation algorithm. The efficacy of this procedure is demonstrated by conducting a few numerical and experimental studies. The outcomes suggest that the developed procedure is able to locate and quantify damages in a semi-rigidly connected structure with significant accuracy.

Keywords: element damage assessment; semi-rigid connection; modal data; inverse problem; stiffness reduction factor; SRF; unified particle swarm optimisation; UPSO.

DOI: 10.1504/IJSTRUCTE.2021.112092

International Journal of Structural Engineering, 2021 Vol.11 No.1, pp.44 - 62

Received: 28 May 2019
Accepted: 23 Mar 2020

Published online: 04 Jan 2021 *

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