Damage detection under ambient vibration by harmony search algorithm

Damage in structural systems induced by vibrations, alternating load cycles, temperature changes, corrosion, etc., constitute a serious technical problem. Smart methods of control and structural health monitoring (SHM) for large structures are, therefore, highly needed. In certain structural applications, moreover, a lack of access to the damaged area imposes an additional constraint on damage identification procedures. One method that may fulfill those requirements is dynamic nondestructive testing, which consists of monitoring changes in the structure's natural frequencies, vibration modes and damping. In this paper, a new approach for vibration-based (SHM) procedures is presented, in an ambient vibration context; this method combines a time domain modal identification technique (SSI) with the evolutionary harmony search algorithm. A series of numerical examples with different damage scenarios and noise levels have been carried out under impact and ambient vibration. Thereafter, an experimental study of three cantilever beams with several different damage scenarios is conducted and the proposed methodology has shown potential for use in the damage diagnosis assessment of the remaining structural life. (C) 2012 Elsevier Ltd. All rights reserved.