| Popis: |
The aim of the work presented here is to develop a pipe inspection tool that is capable of detecting, locating and then sizing any defects that may be present in the pipe section under test. The work is primarily directed towards quantifying any improvements that can be made to the current screening system by using synthetically focused imaging algorithms. The algorithms are first tested for plate imaging using a linear array and then modified for use on cylindrical structures. The minimal modifications make use of similarities between the guided wave structure in plates and pipes. The pipe imaging system is then rigorously tested using data from 3D finite element model predictions and laboratory experiments. The performance of the system is established at various inspection frequencies in terms of detection sensitivity to circumferential cracks, resolution and robustness towards set up errors. It is found that the defect sensitivity is increased by around 15 dB over the simple screening tool and cracks of circumferential extent larger than ~1.5? can be directly sized from the pipe image. |
