Structural health monitoring using acoustic pressure response
Résumé
The subject of structural health monitoring is emerging as an increasingly important component of overall nondestructive evaluation programs.Presently, vibration-based and contact acoustic emission techniques have been widely used for structural health monitoring. Both vibration-based and acoustic emission techniques require attaching transducers to structures. In many applications, such as those involving hot structural materials for thermal protection purposes or in rotating machines, non-contact measurements would be preferred because the operating environment is prohibitive leading to potential damage in contact sensors or their attachments. There are some examples of optical techniques, such as laser-based techniques that do not require contact measurements but these non-contact methods are very expensive with respect to hardware and computational effort. In such cases, non-contact acoustics techniques are a very attractive option for determining the location and extend of damage in the structure. In this paper, a new method of SHM using acoustic pressure response is proposed. In the proposed method, the acoustic pressure responses are used to obtain vibro-acoustic mode shapes of the vibrating structure, which are subsequently used for damage detection of the structure. The proposed acoustic-based SHM facilitates less expensive acoustic field measurements and fast data processing. In total, this will lead to an online structural health monitoring system.
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