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Tuesday, June 24, 2008 - 11:30 AM

Validation of Nondestructive Testing Sensors Used in Structural Health Monitoring

D. S. Forsyth, J. I. Gonzalez, TRI/Austin, Austin, TX; T. B. Mills, C. L. Brooks, AP/ES Inc., Saint Louis, MO

There is considerable interest in aerospace and other industries in the use of sensors for structural health monitoring (SHM) that are derived from or are the same as sensors used for conventional nondestructive testing (NDT) applications. Texas Research Institute Austin (TRI/Austin) Inc. and Analytical Processes/Engineered Solutions (AP/ES) Inc. have collaborated to develop a process for the selection and validation of NDT and other sensors applied to SHM in aerospace structures.

AP/ES has developed and demonstrated a quantitative process for determining optimum sensor selection and application. This process carefully considers costs of implementation and support in operation of SHM, in comparison to existing procedures. Once a cost-effective SHM system has been designed for an application, validation of the SHM system is required just as validation of new NDT procedures is required.

In this work, we discuss the SHM design process, and describe in detail the validation studies being performed by TRI/Austin and AP/ES on sensors for corrosion damage and fatigue damage in aerospace structures. These studies are being performed to demonstrate both the SHM system reliability, as well as the damage detection reliability. Coupon tests using materials, loads, and environments typical of the target application are the key elements of the validation. Results will be presented from these coupon tests.

These efforts are supported by SBIR funding from the Air Force Research Laboratories Materials and Manufacturing Directorate.


Summary: TRI/Austin and AP/ES are collaborating to design and validate structural health monitoring (SHM) systems for aerospace structures using a variety of sensors, including some derived from conventional nondestructive testing (NDT) applications. The sensors and systems must be validated in terms of the system reliability and detection reliability. The systems must function as designed for significant lengths of time, on the order of a few decades, to be cost effective. The probability of detection (POD) of the damage mechanism of interest must also be maintained at the desired level for this time period. Results from current test programs on sensors for corrosion and fatigue damage in aerospace structures will be presented.