Physical Optics Corporation — Department of Defense SBIR Phase I: N161-069

Description

To meet the Navys need for a crack arresting method for welded aluminum structures, Physical Optics Corporation (POC) proposes to develop a new Rapid Aluminum Crack Arresting Kit (RACAK) that uses a proprietary material that rapidly welds a metal patch over the crack area without adding residual stress and to arrest crack growth, a database to help users select the application method, and a sensor to monitor the repaired structure. RACAK uses fumeless, safe, nontoxic welding compound that is made of readily available materials. In Phase I, POC will demonstrate RACAK at lab scale under low-cycle tension-tension fatigue loading conditions. In Phase II, POC will refine the RACAK methodology, expand the low-cycle fatigue testing and analysis to capture higher stress levels and increased stress state complexity with constant and random amplitude fatigue spectrum loading, and demonstrate crack arresting capabilities for full-scale structural components. Detailed numerical analysis will be performed on the experimental testing to develop the loading scenario, facilitate the estimation of a fatigue lifetime limit, and demonstrate the ability of the technology to arrest crack growth or significantly decrease the crack growth rate and increase the load cycles to failure of the repaired plate.