Towards Guided Wave Robotic NDT Inspection: EMAT Size Matters

Abstract

The first steps towards fast robotic screening of wall thinning in the industrially relevant example of 10mm thick steel plates are reported. Electromagnetic acoustic transducers (EMATs) are used to generate and detect guided shear horizontal wavemodes, as these show promise for this type of inspection. EMATs are miniaturised to reduce magnetic drag on ferritic steels, and are designed to produce SH0 and SH1 wavemodes with 22mm wavelength, which is suitable for testing wall thinning in these samples. Miniaturisation and the resulting reduction of magnetic drag force allows the EMATs to be mounted on a small crawler robot which can then be used to scan the sample/structure.