Detecting Crack Nucleation/Damage Mechanisms In Sea-Based Aviation Environments

TDA recognizes the need for analytical formulations for crack nucleation predictions and sensors to detect crack nucleation in environment assisted cracking of Naval aircraft structures. TDA proposes to investigate the role of microstructural damage evolution during pre-crack nucleation and stress field imposition; and methodologies, both electrochemical and electromagnetic, for measuring early response on the development of stress field and initiation of corrosion sensitive zones. This SBIR effort dovetails seamlessly with TDA"s current work with ONR"s UNIGROW-UNICORR program, in addition to the development of sensors for laboratory use as well as for leave-on placements on aircraft. TDA will develop analytical formulations for Navy material-environment systems. The analytical formulations will be incorporated into UNIGROW-UNICORR program to work as a design tool to predict nucleation of cracks in user-selected environment and loading situations. TDA also proposes to develop novel techniques using a combination of DCPD and ECN to detect small cracks. A prototype sensor capable of measuring small micro cracks of 10microns or less in corrosive mediums as well as providing continuous corrosion activity will also be developed. TDA will conduct critical tests using the proposed novel techniques and outline the steps needed for future sensor development.