Dual thermal/electrical-driven compressive recovery behaviors of 3D braided shape memory composite tubes

3D braided shape memory composite (SMPC) tubes have great potential in designing smart structural components because of high inertia moment and near-net shape manufacturing. Here we developed a 3D braided carbon fiber reinforced shape memory polyurethane-based composite tube and investigated their thermal/electrical shape memory behaviors subjected to compression. The radial and axial compressive behaviors, thermally-electrically shape memory behaviors, and shape recovery forces of the SMPC tubes with different braiding angles were analyzed. The out-of-plane displacement and temperature field were obtained with 3D digital image correlation (DIC) and infrared thermography to characterize transverse compression deformation. We found that the 60° sample had the highest recovery force compared to the other braided angle samples, while the shape recovery speed was lower than small-angle samples. In the transverse compressive electro-thermal recovery test, the 30° sample reaches to glass transition temperature faster at the same voltage, and the 45° sample exhibits maximum shape recovery speed. The 3D braided SMPC tubes exhibited excellent electro-thermal shape memory behaviors and high recovery force, which were expected to extend the application of smart actuators.