ASSESSING THE HEALING OF MECHANICAL STRUCTURES THROUGH CHANGES IN THEIR VIBRATIONAL CHARACTERISTICS AS DETECTED BY FIBER OPTIC BRAGG GRATINGS
✍ Scribed by F.G. TOMASEL; P.A.A. LAURA
- Publisher
- Elsevier Science
- Year
- 2002
- Tongue
- English
- Weight
- 104 KB
- Volume
- 253
- Category
- Article
- ISSN
- 0022-460X
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✦ Synopsis
The need for early damage detection in mechanical elements and structures permeates most areas of engineering. This necessity has led to the development of a variety of experimental techniques designed to monitor the structural health of mechanical systems, at both local and global scales. A global approach that has received increased attention during the last decade is that based on the detection of damage through changes in the dynamical characteristics of the structures [1}3]. As faults develop, the changes induced on the sti!ness and inertial properties of the structure modify its modal parameters such as frequencies and mode shapes. Conversely, when the structure is repaired, its physical parameters and, consequently, its modal parameters, should return to values close to those characterizing the original structure. This observation allows for the possibility of on-line monitoring of the healing process by measuring the vibrational characteristics of the mechanical system as a function of time.
This communication presents a simple experimental set-up where real-time assessment of the degree of healing is achieved through measurements of the resonant frequencies of the system with a "ber optic grating. The potential of the proposed set-up is demonstrated for the case of a cracked cantilever beam that is repaired using an epoxy resin. It is shown that the combination of "ber optic gratings and vibration analysis constitutes a promising approach in the development of practical probes for on-line monitoring of curing processes.
FIBER OPTIC BRAGG GRATINGS