<title>Smart coatings for in-situ monitoring of engine components</title>

Abstract

Fatigue cracking and plastic deformation occur in both new and aging aircraft engines, requiring periodic manual inspections with ultrasonic and eddy current probes. Often cracking occurs in inaccessible areas that require engine disassembly just to perform the inspection. In many cases, the cost of assembling and reassembling the engine far exceeds the cost of inspection and can also induce new damage. This paper addresses "Smart Coatings" -under 10 micron thick coatings that contain planar sensors sandwiched between layers of tough protective insulators. The resulting sensing film is much lighter than adhesively attached sensors, and forms a life-extending protective coating that also performs structural sensing.Prototype sensors were deposited onto Inconel 7 1 8 coupons, using standard microelectronic lithography and deposition techniques. The demonstrated sensors include a crackwire sensor for detecting surface cracks and plastic deformation, and a capacitive sensor for detecting surface contamination. The paper will describe destructive tensile testing of Inconel coupons containing the crack and these sensors

An overview of the NASA aviation safety program propulsion health monitoring element

“…The goal is to enhance propulsion safety through the reduction of uncontained engine failures and in-flight shutdowns. Past technology developments to be leveraged and advanced include high temperature thin film sensors 29 (see Figure 7), smart coatings 30 , and ultrasonic piezoelectric transducers. 31 The approach will be to develop and demonstrate this instrumentation and its associated signal conditioning software in component rig tests followed by an on-engine demonstration.…”