S. J. Hudak, B. R. Lanning, G. M. Light, J. A. Moryl, T. H. Jaeckle, Southwest Research Institute, San Antonio, TX

Summary:

Significant enhancements in the reliability and readiness of high-value assets are believed to be achievable by developing and implementing prognosis systems. These systems are based on a real time, or near-real time, decision making process that includes the acquisition and fusion of on-line sensor feedback, combined with physics-based analytical models for damage accumulation, and higher order reasoning for decision making. A key feature of prognosis systems is feedback on the current state of materials damage. This presentation will describe the development of a thin film sensing technology for detection and monitoring of cracking in turbine engine materials. The sensing system includes three key elements – a magnetostrictive thin film for generation and receiving of elastic waves in the 100 kHz to 1 MHz range, a wireless communication system for activating and recording backscattered feedback from multiple distributed sensors, and an energy harvesting system for local power. The presentation will focus on the development of the thin film sensing element and the wireless communication elements of the technology. The primary challenge for these elements of the sensing system are the development and implementing thin films with high Curie temperatures that can tolerate the turbine engine operating environment, and the ability to propagate wireless signals within the complex geometry of the turbine engine core using simple electronics that can be implemented with thin films. A two-phased approach is being pursued with target temperature in 500 F in Phase 1 and 1200 F in Phase 2. Both monolithic and layered films are being developed – the monolithic films serving as a building block for layered nanostructured films, which are designed to meet the elevated temperature challenge. Progress in optimizing the magnetic and magnetostrictive properties of the thin films will be summarized along with their ability to generate guided elastic waves in a variety of engineering materials. Results on propagation of radio frequency waves within the core of a turbine engine for wireless communication will also be presented and discussed.