Non-contact detection of pulsed acoustic displacements for the evaluation of sub-surface defects
conference paper
The development of optical methods for detection of ultrasound is important for the technology of non-contact Non-Destructive Evaluation of materials. Several optical methods are limited in their application by their sensitivity for ambient vibrations or their complexity. In this paper a Fiber Time Delay Interferometer is proposed which can be applied to the detection of pulsed ultrasonic vibrations. A practical instrument has been built with a detection limit of 2.10-11m, determined with a detection bandwidth of 10 MHz. Results of experiments show that the method can be used for the detection of (artificial) sub-surface fatigue cracks, using pulsed ultrasonic excitation.
TNO Identifier
246370
Source title
Proceedings of SPIE, Fiber optic sensors II
Collation
6 p.
Pages
76-81