Multitude of Attritable Composite Structures (MASS)

Attritable vehicles are needed for future highly contested battlefields. These vehicles must be light-weight to meet range and loiter time requirements for far-reaching strike missions or time-intensive intelligence surveillance and reconnaissance missions. Also, for the success of these missions, they must be capable of carrying the required payloads. In order to minimize or completely avoid sustainment costs, the structural soundness of the attritable vehicle must be appropriate for its limited life. To provide the flexibility to counter emerging and changing threats, attritable vehicles must have the capability to be quickly designed, built, and fielded. Most importantly, these systems must be low cost to decrease mission costs, make losses acceptable, and create the potential to surge in numbers and bring the mass of swarms to the fight.

Additive printing of continuous fiber structural composites properties are approaching the mechanical performance of traditionally manufactured composites. They are poised to enable new light-weight designs (including topology optimized and bio-inspired designs), low-cost (perhaps tool-less) manufacturing, rapid design changes for structural composites, and support the larger digital enterprise.

Traditional structural composite materials development would involve fixing manufacturing process parameters and then mechanical validation via a substantial number of test coupons in order to develop a set of “B-basis Allowables” (MIL-HDBK-17-1F (Composite Materials Handbook-17)) and predict failure. An equivalency test matrix would be needed to be completed for changes in the material constituents or process. Both processes are expensive, time-consuming, inhibit agility, and represent a substantial barrier to transition of new composite materials and processes.

The digital enterprise seeks to create digital representations, or “digital twins”, of real world processes, microstructures, properties, vehicle structures, and integrated vehicles to better manage, improve, and exploit opportunities with increased mission effectiveness and decreased development and operational cost. Physics-based, Integrated Computational Materials Engineering (ICME) processing and performance tools have been developed under sponsorship by the Air Force Research Laboratory’s Materials and Manufacturing Directorate and seek to predict the responses to changes in the processing-structure-property relationships. Artificial Intelligence (AI) and Machine Learning (ML) tools for understanding and correlating additive manufacturing processes, microstructures, and properties are also being developed. 

The Structural Materials Division of the Air Force Research Laboratory’s Materials and Manufacturing Directorate (AFRL/RXCC) seeks to leverage and integrate current ICME tools, AI/ML tools, and continuous fiber additively printed composite capability to create a “digital twin” of a new composite material with substantial impact to attritable air vehicles. The same process and material will be evaluated by the traditional, empirically based “B-basis allowables” process and the two processes will be compared in terms of speed, cost, and accuracy to achieve digital-assisted and empirical “B-basis allowables” for a promising new material. The two processes will also be evaluated for their agility to changes in constituents and processing conditions. While firm B-basis allowables targets for attritable vehicles are yet to be established, a broad range of 75-90% of traditional structural composite materials’ allowables is anticipated.