Luna is studying new techniques for quantifying material damage without destructive testing. Through the identification of changes in material organization at the micro- to macro-scales using custom measurement systems and analysis packages, early stages of material degradation related to fatigue, aging, heat damage, and corrosion can be assessed rapidly and reliably, providing robust health metrics for users and maintainers. The transition of this cutting edge technology to embedded hardware for condition-based maintenance will yield significant cost savings and improved reliability for a wide range of commercial applications.
Ultrasonic Micro-structure Evaluation
By passing high frequency sound pulses through an object, it is possible to measure changes in the material’s microstructure. Luna has investigated using this technology in multiple areas, such as the measurement of residual stress in materials due to machining operations and changes in material microstructure due to fatigue to predict future component failure.
Eddy Current Crack Detection
Eddy current testing involves passing an electromagnetic field through a conductive object to measure its material properties. While traditional ultrasonic or laser-scanning techniques have failed to discern damage on the interior of gun barrels, Luna is developing an integrated eddy current sensor, guided by magnetic finite element analysis, to use multi-frequency interrogation of the barrel walls to assess the presence, number, and depth of cracks. A barrel that would normally be decommissioned after a specific number or rounds have been fired, to prevent failure in the field, can now be periodically tested to insure it is safe to use and only decommissioned after its end of useful life has been reached.
Luna has also used eddy current testing to measure the sensitization in aluminum alloys caused by heat damage and will continue to leverage this technology for this and other material testing programs.