Asset Distributed Data Acquisition and Processing Topology (ADDAPT)

CBM+

Problem Statement: Preventative maintenance and inspection intervals for DoD aircraft have been historically aligned with flight and/or calendar hours, set to satisfy a pre-defined acceptable risk threshold. This schedule is predicated on many assumptions, including the aircraft operating consistently with anticipated flight profiles and environmental conditions, and many of the parameters associated with these assumptions—such as strain, vibration and temperatures—were just extracted from limited full-scale ground and flight test aircraft. Furthermore, it is nearly impossible to practically account for unanticipated manufacturing defects and maintenance errors. To bridge the gap between assumptions and experienced conditions, digital twin models have been developed to provide more accurate tail-specific insight on structure health. If properly implemented, digital twins promise to improve maintenance logistics efficiency without compromising accepted risk. However, like most models, digital twin output fidelity is only as reliable as its input fidelity. 

Solution Description:  The Asset Distributed Data Acquisition and Processing Topology (ADDAPT) system was designed as a companion tool for digital twins, serving as a link between the physical and virtual structure to facilitate collection of the multi-physics data points necessary to ensure robust model predictions. ADDAPT has an ultra-low size, weight and power footprint, and provides a plug-and-play daisy-chainable infrastructure for mixed-and-matched analog and digital sensors. It offers the convenience of a common physical, electrical and communication interface to deploy a wide range of off-the-self sensors, whose signals can be selectively gathered continuously in-flight or on-demand post-flight, while being accumulated at a single access point. The intent is for ADDAPT to be networked within the NLign framework such that the collected data can be periodically uploaded to a secure cloud database for convenient access by maintenance facilitators, and eventually incorporated into their respective digital twins. 

In collaboration with the F-15 SPO, a preliminary demonstration has been conducted using ADDAPT integrated with fatigue crack gauges, including flight testing conducted at Eglin AFB. Planning is underway to validate a broader scope of ADDAPT installed on ten F-15 aircraft to assess performance under a cross-section of operating conditions for sensors monitoring fatigue cracks, fastener health, strain, temperature, oil pressure and flow rate, vibration and electrical circuit voltage and current. Real-time data reduction and feature extraction will be conducted for many of the sensors. This work will be conducted in alignment with Aircraft Structural Integrity Program (ASIP) as prescribed through MIL-STD-1530D, the Mechanical Equipment and Subsystems Integrity Program (MECSIP) as prescribed through the MIL-STD-1798C, and Structural Bulletin EZ-SB-24-01 with regards to Structural Health Monitoring (SHM) Systems.