Innovative Unified Damage Mechanisms-Based Model to Predict Remaining Useful Life for Rotorcraft Structures Navy STTR FY2014.A Sol No.: Navy STTR FY2014.A Topic No.: N14A-T002 Topic Title: Innovative Unified Damage Mechanisms-Based Model to Predict Remaining Useful Life for Rotorcraft Structures Proposal No.: N14A-002-0270 Firm: SAFE, Inc. 5032 S. Ash Avenue, Ste. 101 Tempe, Arizona 85282 Contact: Stanley Desjardins Phone: (480) 820-2032 Web Site: http://www.safeinc.us Abstract: A model for structural health measurement is desired that is capable of assessing the accumulated damage and remaining useful life of components post-flight. This model will eliminate the need for load tracking during flight and prevent the additional weight and complexity of components utilized during flight. Safe is partnering with researchers at University of Memphis for this work to relate the current level of accumulated damage in a component/s to the remaining useful life of the component/s. There are multiple technologies available for measuring the amount of accumulated damage in a component, such as acoustic emissions, surface temperature, ultrasound, and electromagnetic readings. Safe's research partners at University of Memphis have demonstrated that acoustic emission technology provides the clearest signal transmission when a damage event occurs. They have established a data-enabled approach to quantify random damage of materials and structures by constructing a measurable multi-variate. This variate can be analyzed by means of mathematical statistics, allowing for data-enabled decision-making concerning material failure. The proposed program will expand the applicability of the already developed model to include additional materials of interest concerning military rotorcraft, as well as refine the model/s to include additional geometries (current models are limited to laboratory samples.) Benefits: Rotorcraft structures are subject to damage accumulation due to the harsh environment and conditions in which they operate. Components are currently designed using a safe-life approach, in which analytical methods are used to calculate the predicted service life of components. While this safe-life approach is beneficial for critical systems that are difficult to repair or can cause serious damage in the event of a failure, the major disadvantage is that the components are retired from use after a specified number of service hours, regardless of the remaining useful life of the component, and consequently some parts are not utilized to their full potential of useful life. Efforts are currently underway to transition from a safe-life design approach to a more efficient conditional maintenance approach, in order to achieve optimum service life out of structural components. Achieving the proposed long-term goals of the program will allow operators of rotorcraft to extend the service life of both fielded and new hardware, lowering the overall cost of operating the rotorcraft. Return