• An embeddable sensor based on chirped fibre Bragg gratings (CFBGs) was achieved for in-situ and direct wear measurement of a full-size water-lubricated bearing (WLB). • The sensor not only demonstrates high measuring resolution, accuracy and excellent repeatability, it also exhibits robust sensing stability regarding temperature and force variation among common WLB working conditions. • Wear monitoring of a full-size WLB during an 88h test reveals a tiny signal fluctuation within ±0.04 mm upon dynamic conditions and an average measuring error of about 0.1 mm. Water-lubricated bearings (WLBs), which support the stern shaft of ships, are prone to severe wear due to their harsh working environment. The mechanism of wear occurrence as well as a universal method for improving bearing wear resistance still remain challenging because the real-time wear of bearing lining is inaccessible during service. In this work, we propose an embeddable sensor based on chirped fibre Bragg gratings (CFBGs) for in-situ and direct wear measurement of WLBs. The developed sensor features excellent sensing resolution (superior to 0.1 mm) and accuracy (±0.1 mm@8 mm). Moreover, it also demonstrates fascinating measuring repeatability (over 100 tests) and robust sensing stability regarding temperature and force variation among common bearing working conditions. Although temperature or static/dynamic forces cause measuring error when the CFBG is encapsulated into bearing lining materials, these errors (mostly within ±0.15 mm) are comparable to sensing accuracy. Finally, the developed sensor was applied to monitor the wear of a real WLB during a long-term experiment. Shaft rotation causes minor measuring error (within ±0.04 mm) to CFBG which depends on rotary speed. A 4 h successive monitoring reveals the robust sensing capability of CFBG under dynamic conditions. Comparing the CFBG measuring wear to the variation of bearing inner diameter during a 112 h wear test results an average error of less than 0.10 mm. Such outcome further validates the feasibility and superiority of the developed wear sensor for WLBs wear characterization. This study provides a new routine for in-situ and direct wear monitoring, which is of great significance for fault diagnose and remaining life prediction of WLBs.
Wu et al. (Fri,) studied this question.