Excitation and propagation of ultrasonic guided waves in pipes by piezoelectric transducer arrays

Ultrasonic guided wave inspection is one of the non-destructive testing (NDT) techniques available for the structural health monitoring (SHM) of engineering structures. Compared with other NDT techniques, guided waves can propagate over tens of metres with a relatively high sensitivity to defects in the structure. The general sensitivity range of the operation is up to 3% reduction of the cross-sectional area, depending on the signal-to-noise ratio. However, optimisation of guided wave testing method is still a requirement, as the technique is currently subject to a complex analysis due to wide number of guided wave modes generated. This can be done by optimising the transducer array design. In this paper, it is described the behaviour of a set of piezoelectric transducer arrays upon excitation in a tubular structure with simulated defects. This is achieved through a combination of finite element analysis (FEA) and experimental testing. The core objective of the work is to optimise the design of transducer arrays aimed at exciting the T(0,1) mode with a significant level of mode purity. This will significantly reduce the complexity of guided wave analysis, enhancing effectively the structural health of structures and subsequently reduce the industry maintenance cost.