Title: Performance and Durability Assessment of Shape Memory Polymer Tools for Closed Composite Structures
Authors: Christian Pfledderer, Steven Shewchuk, Craig Neslen, Elizabeth Loiacono, Thomas Margraf, Michael Matlack
Abstract: Shape memory polymer (SMP) tools that are rigid for lay-up, elastomeric for cure, and reformed into the inside mold line (IML) shape of the composite article between cycles. They have been used to control the inner geometry of composite structures. SMP tools are fabricated using resins formulated to have an elastic modulus that changes depending on the material temperature and the specific material formulation. At room temperature, the SMP tools have a high elastic modulus (i.e. rigid epoxy), in their rigid state, and can be used as lay-up mandrels to apply composite pre-preg, apply dry fiber textiles, or used as a mandrel during an overbraid process. At cure temperatures, SMP tools classified as bladders and cauls transition to a highly elastomeric state (i.e. medium durometer silicone), and when internally pressurized, transfer compaction force into the composite laminate to ensure good material consolidation during the cure process. This paper describes the application of SMP tools to the fabrication of a double I-beam composite design using composite pre-preg material. Part to part geometrical accuracy, part porosity, surface roughness, and a durability evaluation of the SMP tooling was completed after 59 thermal and/or laminate cycles in the double I-beam configuration.
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Conference: SAMPE NEXUS 2021
Publication Date: 2021/06/29
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