Low-Power Wireless Near-Field Light Scattering Structural Health Monitoring

Reliable and operationally simple methods that can be used in the field are needed for expeditious fatigue damage and corrosion detection. We have developed a strategy for constructing a laser-based nondestructive sensor for fatigue and corrosion damage detection and monitoring in aerospace components. The sensor detects precursors to crack formation occurring as early as the first 10% of fatigue life and, therefore, can be used to identify accumulated fatigue damage prior to crack initiation. The sensor can also be used to detect the state of surface corrosion formation. During Phase I, we will demonstrate proof-of-concept of a new ultracompact version of this leave-in-place nondestructive optical sensor. This new version of the sensor will tolerate high-G conditions better and support remote wireless interrogation of the retrieved data. This new design has the ultimate potential to be fabricated as a single-chip component. During Phase II, we will further refine our work in modeling the instrument, designing its specific components, assembling it, and establishing its performance envelope. Phase II will culminate in constructing and field-testing the prototype system.BENEFITS: Since over 90% of mechanical failures are due to fatigue damage, the proposed sensor will be useful in a variety of industries that employ dynamically loaded mechanical systems. Of particular significance are the commercial and military aircraft industries, where the instrument could be used to quickly verify the safety condition of many critical parts, such as engine components, fuselage panels, and landing gear. If unchecked, fatigue-induced damage in airframe components can lead to formation of cracks. Crack formation is often followed by sudden catastrophic failure of the airframe component and destruction of the aerospace vehicle. By providing a timely warning, the proposed sensor will assist in identifying potentially damaged components and, in this way, will improve safety of aerospace vehicles while reducing maintenance costs. In addition, many other industries can benefit from this diagnostic tool, including the automotive, power generation, shipping, and railroad industries.