Hybrid Fiber Optic Sensor Systems in Structural Health Monitoring in Aircraft Structures

Abstract

‘Smart’ structural health monitoring of composite materials with optical fiber sensors is becoming more and more important, especially in the aviation industry. This paper presents an overview of hybrid fiber-optic sensing systems based on scattering techniques, fiber Bragg gratings, interferometric techniques, and polarimetric methods in structural health monitoring. The main purpose of this manuscript is to analyze the possibilities of using hybrid sensors based on fiber optics to monitor composite structures, with a particular emphasis on aircraft structures. Since it is difficult to indicate the most comprehensive approach due to different parameters of the described sensors, the review contains a detailed description of available solutions. We hope that this work will allow for a better and faster selection of the right solution for the problem at hand.

Structural Health Monitoring in Composite Structures: A Comprehensive Review

“…Any SHM system requires a data-collection mechanism, for which different types of sensors can be selected depending on the type of data required for damage detection. Some commonly used sensors include strain gauges [ 98 ], accelerometers [ 99 ], temperature gauges [ 100 ], acoustic emission sensors [ 101 ], and fiber optic-based sensor systems [ 102 ]. Several factors to be considered prior to select sensors for an SHM system are described as follows: Type of sensors; Sensor cost(s); Number of sensors and their installation procedure; Damage protection against mechanical and chemical factors; Reduction in the effect of noise; Data-collection procedure; and Sensitivity of sensors to long-term environmental effects, such as moisture and humidity.…”

Fiber Bragg Sensors Embedded in Cast Aluminum Parts: Axial Strain and Temperature Response

“…Note that in this case, the strain and internal pressure are independent of the radii and are dominated by the difference of the CTEs. According to Equations (6) and (8), the axial and radial strains induced by the aluminum depend nonlinearly on temperature because temperature-dependent parameters for Young's moduli, Poisson's ratios and thermal expansion coefficients should be used in the extended temperature range considered here. The temperature-dependent parameters are listed in Table 1.…”

“…Monitoring of functional parts is of great interest and could help to improve the lifetime of these parts or to avoid failures in advance [ 1 , 2 ]. In the field of aerospace, embedded fiber optic sensors have been used as a real-time monitoring system in an aircraft with single-point, multi-point, or distributed sensors [ 3 , 4 , 5 , 6 ]. For structural health monitoring (SHM), embedded sensors are beneficial since they are permanently installed, can be positioned at critical points within the structure, and they receive protection and robustness from the structure itself.…”

Fabrication and Sensing Application of Phase Shifted Bragg Grating Sensors

“…These characteristics make them very suitable for application in the fields of biomedicine, the petrochemical industry, aerospace, etc. [ 11 , 12 , 13 , 14 ]. Fiber Bragg grating (FBG) is an important part of optical fiber sensors which has many advantages such as compact structure, distributed measurement, small transmission loss and anti-electromagnetic interference [ 15 ].…”