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The Aircraft Component Remaining Useful Life Evaluator (ACRULE) is an engineering analysis tool that calculates the remaining useful life (RUL) for H-60M airframe and dynamic components based on actual usage. Off-board regime recognition (RR) algorithms process raw data files from the Integrated Vehicle Health Management System (IVHMS) to determine usage. Regime sequence results for each flight are sent to damage calculation programs that compute each regime’s fatigue damage contributions as well as the maneuver-to-maneuver (or low-cycle) damage for the flight. The final RUL calculations rely on statistical analysis of historical usage for individual tail numbers and the fleet usage distributions to determine replacement times with the same reliability as the baseline component retirement times.

Results of the RUL calculation process are stored in a database along with maintenance history to determine when a component is removed or installed each tail number in the fleet. This data is displayed to the end user through Tableau dashboards made available to Army engineering, program office, and maintainers on the Aging Fleet Integrity & Reliability Management Multi-Platform (AFIRM-M) website maintained by MERC.

Two finite element models of the H-60M were built during this effort to support fatigue spectrum development of airframe tracking locations. The fatigue spectra were derived using flight strain survey data combined with loads regression methods developed at MERC. The models contain over 1M elements with a nominal one inch element size. Additional refinement down to a tenth of an inch was made in the areas of the tracking locations. The models are used with multiple mass configurations to develop unique fatigue damage estimates for different mission profiles.


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