Abstract:
In order to enhance the compression strength of three-dimensional woven spacer composites and improve its compression energy absorption, inspired by the design concept of multi-layer sandwich structure, three-dimensional woven double spacer composites with pile height of (6+6) mm and (4+8) mm were designed and fabricated. The flatwise compression and edgewise compression properties and failure modes of the double spacer composites were investigated by comparing with the single spacer composites with the pile height of 12 mm. The results show that the flatwise compressive strength, edgewise compression strength and energy absorption of the two double spacer composites are improved significantly compared with that of single spacer composites. Among them, the flatwise compression strength (11.5 MPa) and specific energy absorption value (6983.7 J/kg) of the double spacer composites with pile height of (6+6) mm are increased by 57.5% and 152.4%, respectively. In addition, the flatwise compression failure mode of the double spacer composites is the fractures of the pile yarns layer by layer, and the edgewise compression failure mode is crack propagation of panel, which show greater energy absorption characteristic. The design of double spacer structure not only enhances the flatwise compression and edgewise compression properties of three-dimensional woven spacer composites, but also optimizes its failure modes, which improves the safety of spacer composites in practical application, and provides a new idea for the structural design of spacer composites with higher pile height or multilayer.