Abstract
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.
Highlights
Structural integrity evaluation of oil and gas pipelines with non-destructive testing (NDT) and structural health monitoring (SHM) techniques is attractive in industrial fields, since serious accidents of pipe failures have occurred due to its wallthickness loss by corrosion or fatigue cracks, commonly
This paper presents wave mode T(0,1) which was excited to propagate on a 4.45 m long, 8-inch (219.1 mm outer diameter), schedule 40 (8.18 mm wall thickness) steel pipe using the transducer array with a 33-degree gap and verified through experimental validation
Results show that a 0.5 mm width, through-thickness crack size can be detected by exciting wave mode T(0,1) at 35 kHz in numerical simulations, even the detection is without complete signal transmission from the transducer arrays
Summary
Structural integrity evaluation of oil and gas pipelines with NDT and SHM techniques is attractive in industrial fields, since serious accidents of pipe failures have occurred due to its wallthickness loss by corrosion or fatigue cracks, commonly. The dispersion curves were generated to describe a relationship between the selected modes and their flexural wave modes in a frequency range from 0 to 50 kHz [4] as shown in paper [5]. 24 transducers in each ring excited the torsional wave mode T(0,1). The torsional type flexural wave mode F(1,2) as shown in Fig. 2 and its higher order modes were generated to interact with the wave mode T(0,1) by a transducer array with a 33-degree gap [7]. This paper presents wave mode T(0,1) which was excited to propagate on a 4.45 m long, 8-inch (219.1 mm outer diameter), schedule 40 (8.18 mm wall thickness) steel pipe using the transducer array with a 33-degree gap and verified through experimental validation. Its sensitivity analysis was evaluated for circumferential crack detection
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