Within the Optical Instrumentation and NDE branch is the expertise for structural health monitoring (SHM), nondestructive evaluation (NDE), and damage characterization of advanced materials (metallics and composites).

Recently, the focus has been on SHM of critical turbine engine components such as disks, blades, shafts, and bearings. Both global and local approaches have been developed and verified. The global techniques include passive (e.g., blade tip displacements and shaft vibrations) and active (e.g., active magnetic bearings for pulsing and listening) vibration monitoring with accompanying physics based models, while the local techniques include wireless ultrasonic and impedance based sensors that “ride” on the rotor. In addition to the in-situ approaches, various NDE techniques are being studied for enhanced damage detection during nightly or periodic tear-down inspections. These techniques include ultrasonics (guided wave and non-linear), thermal wave imaging and thermoelastic stress analysis. The goal of the enhanced NDE is to identify precursors (e.g., voids along grain boundaries, micro-cracking, initiation of corrosion, etc.) of creep, fatigue, and environmental damage prior to the formation of macro-cracks or other easily observable forms of damage. Furthermore, because there is a need to fully understand the materials of interest, material characterization studies are conducted on advanced metals as well as composites. During these tests the mechanical behavior is studied by implementing various NDE techniques to help in grading the damage level within the material systems.
POCs: Dr. Andrew Gyekenyesi, Dr. Jerzy Sawicki, Dr. George Baaklini