SBIR-STTR Award

Minimally operating or non-operating systems provide little or no opportunity for measuring functional parameters as they degrade, reducing visibility into the condition of system reliability. The negative effects of this phenomenon are seen to a greater degree in systems that are required to operate once with near-perfect reliability following a period of prolonged dormancy. Cruise missiles that require minimum maintenance and inspection throughout their lifetimes do not have a methodology to properly predict the reliability of the subsystems . Nuclear cruise missiles may be stored on a pylon in uncontrolled environments for six years between major maintenance actions, with minimal testing performed every two years. Phase I of this effort is focused on defining the current state and evaluating the methodologies necessary to obtain a predictive model for the entire missile as the sum of its LRUs. Phase II will involve integrating these models into the Sherlock architecture to provide both LRU level and an aggregated missile level reliability prediction.

Benefits:
A tool that provides a prediction model of LRU level reliability for aging weapon systems that can be used to establish maintenance and replacement schedules and provide targeted preventative and life extending repair during depot level maintenance periods. Supplier participation will improve the accuracy of the predictions by bringing a greater level of fidelity to the design files being analyzed while allowing for more effective design decisions throughout their design development process. Ultimately, as part of the Model Based Engineering initiative, the DoD is expected to establish a neutral exchange or repository, where design data can be used as inputs to reliability models without compromising the integrity of the intellectual property. Tools based on the technology developed during this project will allow the Air Force to leverage this data to drastically improve the average total cost of ownership through more informed maintenance actions. Also, as the availability of quantified Physics of Failure based reliability analyses increases, they are expected to become a greater factor in the government procurement process.

Keywords:
Prediction, Reliability, Methodologies, Dormant, Subsystems, Line Replaceable Units, Nuclear, Aging Systems

This effort focuses on developing a method to aggregate physics based reliability predictions in dormant missile systems. The approach to aggregating these predictions can be similarly applied to non-dormant systems. DfR Solutions will explore dormant failure mechanism models and produce a tool that allows system aggregation of LRU level analysis results. Reliability models for aging solder joint survivability and thermal battery humidity degradation will be developed and combined with existing physics based reliability models in a tool to provide LRU reliability predictions. A systems level tool will then be developed to aggregate LRU reliability predictions at the system level.

Benefits:
Using the resulting tools, dormant system maintenance can be scheduled based on improved information. Commercial systems developers will be able to integrate reliability analysis into their existing model based engineering practices. LRU suppliers will be able to provide customers insight into the expected reliability performance of their products, and contribute in a collaborative way without exposing the intellectual property associated with their design.

Keywords:
Solder Joints, Thermal Batteries, Reliability Prediction, Model Based Engineering, Missile, Dormant Systems, SysML, Automated Design Analysis