Novel Fiber-Optic Ring Acoustic Emission Sensor

Abstract

Acoustic emission technology has been applied to many fields for many years. However, the conventional piezoelectric acoustic emission sensors cannot be used in extreme environments, such as those with heavy electromagnetic interference, high pressure, or strong corrosion. In this paper, a novel fiber-optic ring acoustic emission sensor is proposed. The sensor exhibits high sensitivity, anti-electromagnetic interference, and corrosion resistance. First, the principle of a novel fiber-optic ring sensor is introduced. Different from piezoelectric and other fiber acoustic emission sensors, this novel sensor includes both a sensing skeleton and a sensing fiber. Second, a heterodyne interferometric demodulating method is presented. In addition, a fiber-optic ring sensor acoustic emission system is built based on this method. Finally, fiber-optic ring acoustic emission experiments are performed. The novel fiber-optic ring sensor is glued onto the surface of an aluminum plate. The 150 kHz standard continuous sinusoidal signals and broken lead signals are successfully detected by the novel fiber-optic ring acoustic emission sensor. In addition, comparison to the piezoelectric acoustic emission sensor is performed, which shows the availability and reliability of the novel fiber-optic ring acoustic emission sensor. In the future, this novel fiber-optic ring acoustic emission sensor will provide a new route to acoustic emission detection in harsh environments.

A Review of Approaches for Mitigating Effects from Variable Operational Environments on Piezoelectric Transducers for Long-Term Structural Health Monitoring

“…Optical fiber-based SHM systems are less sensitive to temperature and insensitive to electromagnetic interference, see, e.g., [ 62 ]. Optical fiber-based transducers for Acoustic Emission at elevated temperatures have been developed, e.g., for measurements of metal corrosion processes by [ 63 , 64 ]. Non-contact measurements for SHM are also an option, see, e.g., [ 65 , 66 , 67 , 68 ].…”

Coherent Fiber-Optic Sensor for Ultra-Acoustic Crack Emissions

“…There are two main approaches to lengthen the sensing fiber: by wrapping the fiber in a coil around a solid cylinder (solid cylinder transducer, SCT) or by arranging it in multiple loops (stand alone spiral, SAS). The first approach is the one adopted in [26], in which the fiber was wrapped around an acrylic skeleton and tested for AE sensing with an aluminum plate. This solution offers the possibility to wrap meters of fiber and, thus, to easily increase the sensing fiber length; however, since this type of transducer does read the strain induced by the acoustic wave traveling in the cylinder, it suffers from energy dissipation due to the interface between the cylinder and the metallic plate under test.…”

Identification of Fatigue Damage Stages in Polymer Composite Materials by using Acoustic Emission: Approach and Perspectives

“…In turn, fiber-optic acoustic sensors (FOS) with distributed sensitivity represent one of the most promising means for implementing a system for monitoring a PCM with a complex structure [31][32][33]. Sensing optical fibers can be embedded in PCMs during their manufacturing [34][35][36]. This makes it possible to ensure the coverage of the entire surface of the objects by transducers sensors, which is required for monitoring the state of structural elements.…”