Acoustic Inspection Method and Apparatus Therefor

Abstract

The invention provides a method and apparatus for acoustically inspecting a composite repair on a metal structure, the composite repair comprising at least one layer of a composite material applied to a metal substrate of the structure in a repair zone. The method comprises exciting the composite repair within the repair zone using a broadband acoustic excitation signal, and receiving and analysing acoustic data from the first acoustic scan to determine at least one approximate location of one or more defects in the repair zone. In a second acoustic scan, the composite repair is excited in the at least one approximate location using an acoustic excitation signal with frequency characteristics selected to excite the composite material in preference to the metal substrate, and receiving and analysing acoustic data from the second acoustic scan to enable the one or more defects to be characterised as being present in the least one layer of a composite material or present in the metal substrate. In an aspect of the invention, an acoustic probe assembly comprises a housing and first and second acoustic transducer subassemblies arranged in the housing. The first and second acoustic transducer subassemblies are configured to enable operation as a transmitter and a receiver respectively, and each of the transducer subassemblies is elongated along a respective axis of orientation, has a first end configured to contact against a material to be inspected, and is axially movable within a respective bore of the housing. The first ends of the first and second transducer subassemblies are biased towards an extended position in a direction towards the first ends; and the axes of the first and second transducers are inclined towards one another.

Dependencies are inferred from the claim text.