Self-Deploying Trusses Containing Shape-Memory Polymers

Tag : cyanate ester
When cooled below T g , the SMP reverts to a rigid state and holds the truss in thestowed configuration without external constraint. Heating thematerials above T g activates truss deployment as the composite material releasesstrain energy, driving the truss to its original“memorized” configuration without the need for furtheractuation. Laboratory prototype trusses have demonstratedrepeatable self-deployment cycles following linear compactionexceeding an 11:1 ratio (see figure).
While this new truss technology exhibits some functionality similarto that of cold hibernated elastic memory (CHEM) structuresdeveloped in other NASA-sponsored research (previously reported in NASA Tech Briefs ), there are important distinctions. First, the CHEM SMP is basedon a thermoplastic resin, while the new truss material’shigh-performance SMP is a fully cured thermoset resin. Thehigh-performance SMP molecular design has been implemented in avariety of resin systems, enabling resin selection for desiredstructural properties while enabling selection of a required Tg(e.g., 25–225 °C achievable in high-performance SMPsbased on cyanate ester). Also, CHEM-based structures useunreinforced foam as the active component. In the new compositetruss design, the high-performance SMP is integral to thestructure, simplifying the design and increasing the savings inmass, cost, and system complexity. Structures employinghigh-performance SMP are fabricated using the same processes asconventional composites. The composite structure’s mechanicalproperties at temperatures below T g are unaffected by repeated stowage-deployment cycles.
This work was done by Robert M. Schueler of Cornerstone ResearchGroup, Inc. for Glenn Research Center. Inquiries concerning rightsfor the commercial use of this invention should be addressed toNASA Glenn Research Center, Innovative Partnerships Office, Attn:Steve Fedor, Mail Stop 4–8, 21000 Brookpark Road, Cleveland,Ohio 44135. Refer to LEW-17982-1.