Abstract
In-service non-destructive testing of aero-engine components is challenging for conventional ultrasonic techniques due to their contact nature, the complex geometry of engines and restricted access. Cheap optical transducers (CHOTs) employ principles of laser ultrasonics to remotely generate and detect ultrasound, providing a simple non-contact, couplant-free alternative to the traditional piezoelectric transducers. They are practically weightless nanometre-height patterns attached or printed on the component, and activated by lasers. Cheap, with minimal surface impact CHOTs could be permanently left on the component, used in large numbers or as disposable transducers. Combined with an endoscopic light delivery system to provide access via existing service ports in the engine, they are designed to perform remote ultrasonic inspection in an aero-engine environment. In particular, CHOTs would enable in-situ testing of aero-engine blades, reducing servicing time and costs. This paper presents the developed endoscopic CHOTs instrumentation and experimental results of the remote ultrasonic inspection with surface acoustic waves