Multifunctional Composite Materials
via 3D Printing and
Multi-functional composites – materials in which additional functions exist beyond a primary structural function – offer the promise of improved system performance through the reduction of redundancies and reduced safety factors. Similarly, automated manufacturing processes for composites enable new levels of reproducibility and traceability that reduce uncertainty and allow reductions in overdesign. Yet today’s manufacture of multifunctional composites relies on hand lay-up or ad hoc approaches. In this talk, the potential of synthetic microvasculature for multi-functionality is discussed in the context of initial prototyping work, as well as with regards to design for automated and scalable manufacture.
Microvascular materials offer a route to achieve repeated self-healing of a facture location, thermoregulation, and other fluid transport-mediated functions. These functions rely on the mass transport of reactive chemistries or thermal fluids through pre-embedded microchannels. These microvascular geometries are defined sacrificial materials. Our initial studies use sacrificial materials deposited by additive manufacturing. This talk will cover the important considerations of ink development and processing conditions in order to obtain high fidelity features. Attempts to pattern these networks in a scalable manner via highly parallelized multi-nozzle printheads are also presented which increase build speeds by two orders of magnitude.
Subsequent efforts utilize sacrificial thermoplastic filaments that are catalyzed to rapidly depolymerize at elevated temperatures to define vascular features. The chemistry is scaled via melt extrusion of filaments that are co-spooled onto pre-preg tapes suitable for automated fiber placement (AFP) or 3-D printed onto composite plates. Experimental manufacturing case studies for these and other materials systems are performed on a commercial 5-axis gantry-style AFP machine. The performance of the resulting composites, which are designed for aerospace-grade applications, are subsequently tested with respect to their self-healing and thermal functions, as well as to their mechanical integrity. Design guidelines resulting from these studies enable composites fabricators to narrow their design space to target realistic performance specifications and to minimize challenges in fabrication of next-generation multifunctional composites.