Sheath-outside AE monitoring method for multiple sources of damage to cables considering the effect of an HDPE sheath on AE propagation

Cable is one of the important components of cable-stayed bridges, there are three common damages: broken wire, corrosion and fatigue. High-density polyethylene (HDPE) sheaths will induce the attenuation of acoustic emission (AE) signals of damage to cables. Therefore, three cables with different wire counts are used for AE monitoring. The relationship between the thickness and the AE transmittance coefficient of HDPE sheaths, and a circumferential AE attenuation model are established for each cable. According to the transmittance coefficient and circumferential attenuation model, a sensor arrangement method for monitoring the wire breakage, corrosion, and fatigue of cables is quantitatively given. The results show that the transmission coefficient linearly decreases with an increase in HDPE sheath thickness with a slope of approximately 0.012. The circumferential AE amplitude attenuation rates for the three types of cables are 9.9%, 18.74%, and 21.13%, respectively. Monitoring the wire breakage requires only one sensor; monitoring corrosion and fatigue damage only requires one sensor for the 61-strand cable, symmetrical-arrangement two sensors for cables with 349 and 547 strands.