Effect of Thread Count on the Shear Mechanical Properties and Dynamic Mechanical Properties of Shape Memory Polymer Reinforced by Single-Ply Weave Fabric

Shape memory epoxy polymer reinforced by single-ply weave fabric (SMEP-W) possesses high specific stiffness, good foldability, and satisfactory shape memory capability. These advantages make them promising materials for deployable space structures and increasingly attract research interests. Understanding the influence of weave structures on static and dynamic mechanical properties is crucial to structural design and mechanical response prediction. In this paper, a recently developed SMEP-W was prepared. The static shear experiments were conducted through modified shear test fixtures, and the stress field under static shear load was simulated through a multi-scale numerical modelling method. The dynamic mechanical analysis was carried out to evaluate the shape memory capability. SMEP-W shows nonlinear mechanical behavior under in-plane shear load, especially for the one with less thread count. The increase in the number of threads enhances the constraints between warp yarns and weft yarns, leading to an increase in shear modulus and reducing the scattering of static mechanical properties. The stress distribution on the yarns has the characteristic of center symmetry. High-stress regions appear on the overlapping surface of the crossover regions. Compared with shape memory epoxy polymer (SMEP), the glass transition temperature and damping coefficient of SMEP-W are significantly reduced, and the stiffness is remarkably enhanced. The difference in thread count between warp direction and weft direction does not notably affect the glass transition temperature and tan & delta;, but has a remarkable influence on the storage modulus. The present work could provide basic observation for understanding the influence of thread count on the shear mechanical properties and dynamic mechanical properties of SMEP-W.