Fatigue Crack Propagation Monitoring Using Fibre Bragg Grating Sensors

Abstract

The paper presents the analysis of the possibility of fatigue crack detection and monitoring its propagation process using fibre Bragg grating (FBG) sensors. The investigations were carried out on an aluminium alloy sample (a part of the Mi-2 helicopter rotor blade). During the fatigue test, the sample was equipped with FBG sensors applied for strain measurement and the vibration-based strain monitoring. It was observed that the strain curves determined by the FBG sensors agreed well with the fatigue force profile. However, the strain curves were almost insensitive to the crack propagation process, except in the last stage of the test, when the crack length was equal to 25 mm. The strain values and the natural frequencies of the sample that were determined experimentally were compared with the values achieved from the finite element method model, with both methods showing good agreement. Additionally, spectrogram-based analyses were performed, focused on the acoustic waves phenomena related to a crack propagation process. It was confirmed that the proposed signal processing method, based on spectrogram analyses, can be applied for the detection of fatigue crack development in metal structures.

Monitoring the safety status of service bolts in mining roadways

“…Liu (2021) et al applied FBG sensing technology, combined with additive manufacturing technology, to develop sensors to monitor the internal pressure of the soil [ 6 ]. Mieloszyk Magdalena (2021) proposed a feasibility analysis using FBG sensors to detect fatigue cracks and monitor their expansion process [ 7 ]. It can be observed that the application range of FBG sensors is rapidly expanding, with obvious advantages of multiple parameters, scales, and dimensions [ 8 ].…”

Model of the Temperature Influence on Additively Manufactured Carbon Fibre Reinforced Polymer Samples with Embedded Fibre Bragg Grating Sensors

“…The deficiency of trusted reliable in-situ monitoring for purposes of controlling the building process and final product quality has prevented AM technology from developing [ 13 ], thereby embedding FBG sensors within composite structures is necessary for real-time monitoring of temperature alterations and measurements of induced residual strains. It is also a highly innovative and promising technique in order to identify significant process defects while manufacturing samples [ 14 ]. Temperature [ 15 ] and strain [ 16 ] have been mostly measured in Structural Health Monitoring systems through FBG sensors.…”