Ultrasonic guided wave-based testing technique for inspection of multi-wire rope structures

• Propagation of ultrasonic guided waves along a multi-wire rope has been investigated.
• The asymmetric distribution of amplitudes around the multi-wire rope was obtained.
• Special ultrasonic contact-type ultrasonic transducers were developed.
• The amplitude drop over defective strand was observed.
• The technique for identification of particular defective strands has been developed.

The aim of this paper is to investigate the propagation of ultrasonic guided waves (UGW) along multi-wire ropes with polymer cores and to determine whether it is possible to detect defects and to identify a defective strand inside the internal structure of a multi-wire rope. The modes of UGW that propagate along multi-wire ropes have been identified using modelling wherein dispersion curves are calculated using the semi-analytical finite element (SAFE) technique. The optimal excitation regions were estimated using 3D FE modelling. An ultrasonic testing technique to identify particular defective strands inside the internal structure of a multi-wire rope was developed and verified experimentally.