Repeated Large Deformation Bending Damage and Viscoelastic Characterization of Single‐Ply Fabric Reinforced Polymer Composite

ABSTRACT Single‐ply fabric reinforced polymer composites (SpFRPCs) are promising materials for deployable space structures due to their temperature‐dependent mechanical properties and large deformation bending capability. Before reaching the operational configuration in space, deployable structures undergo repeated bending during ground‐based folding‐unfolding tests, stowage and on‐orbit deployment. This study investigates the damage introduced by repeated large deformation bending in the rubbery state and the corresponding influences on viscoelastic bending in the glassy state of SpFRPC. Dynamic mechanical analysis identifies the glass transition temperature to be approximately 21.5°C. Accordingly, 10°C and 60°C are selected as the representative glassy and rubbery states for bending experiments. The novel column bending test is employed with a specially designed loading protocol consisting of folding, relaxation, unfolding, and recovery steps. An elastic unidirectional glass fiber‐reinforced PEEK composite is tested for comparison. Following repeated loading, microscopic observations reveal kinking and bending damage in the reinforcing fabric, accompanied by a reduction in bending stiffness from 405.4975 to 212.4908 Nmm ² per 1 mm specimen width. The viscoelastic bending parameters are experimentally characterized and implemented into the finite element modeling.