Investigation of effects from realistic influences on inductive gap measurement

Abstract

Abstract The influence of deviations from ideal square butt joint conditions is investigated for an improved inductive gap measurement method. Varying plate thickness, chamfers, and scratches are tested on Alloy 718 at different frequencies in a working range around the gap. Results for different plate thickness show that measurements of position and gap width are affected at all frequencies tested. For a chamfered plate, position measurement is affected for all frequencies, while gap width measurement is less affected at higher frequencies. For both a narrow and a wide scratch, the position measurement at the highest frequency is affected for all scratch locations, while for gap width measurement, only the wide scratch is affecting for all locations. Errors in measurement of probe height and plate alignment are smaller than 0.04 and 0.05\u202fmm for all situations. The results will support in selecting coil frequency and predict results in non-ideal conditions.