An array waveguide probe for detection, location and sizing of surface cracks in metals

Abstract

The paper describes the development of a novel microwave probe for detection, location and sizing of surface cracks in metals. The probe utilizes the inherent mutual coupling in an array structure to determine crack alignment, placement and dimensions. The main feature of the probe is its ability to electronically scan the region of concern, thus avoiding the large inspection time and unwanted noise experienced in the conventional mechanical scanning. Theoretical and experimental results are presented for a prototype two-cell array probe when scanning a metallic specimen containing a long surface crack. It is shown that the probe is capable of determining the orientation, location and dimensions of surface cracks of a few millimeters depth.