Simultaneous monitoring of crack signals and strain of composites using a stabilized EFPI sensor system

Abstract

An extrinsic Fabry-Perot interferometric (EFPI) sensor is a good transducer for the detection of ultrasonic fracture signals and for the measurement of structural strain. In this paper, we report on the development of a novel sensor system, used both to measure the strain of structures and to detect fracture signals of composites, simultaneously. The proposed system solved both the inherent ambiguity in the cosine response and the fade-out problem, which are serious obstacles to overcome before the application of the EFPI to fracture signal detection and to structural strain measurement.