Richard D. Hreha

High-temperature reusable shape memory polymer mandrels

Cornerstone Research Group, Inc. (CRG) has demonstrated the feasibility of filament winding complex-curved composite shapes on shape memory polymer (SMP) mandrels. SMPs can exhibit a radical change from a rigid polymer to a flexible, elastic state, and then back to a rigid state under thermal stimuli. SMP mandrels for filament winding and fiber placement allow for a quick, easy, reusable, and low-cost mandrel system. CRG has recently improved the SMP mandrel technology by adding a high-strain fiber reinforcement (HSFR) that both raises the toughness of the SMP and allows the SMP to elongate up to 150 percent. The resulting material can produce mandrels durable enough to withstand multiple use in high production rate manufacturing. This paper will demonstrate and discuss the feasibility of HSFR-SMP mandrels for filament winding and fiber placement and recent developments in CRGs SMP mandrel technology, including the fabrication of larger parts.