Effects of Face Sheet Structure on Mechanical Properties of 3D Integrated Woven Spacer Composites

Due to the lightweight, structural integrity, superior heat and sound insulation performance, three-dimensional (3D) integrated woven spacer composites are expected to be used in many fields such as marine, automotive, electronics, and building industries. This paper reports the effects of face sheet structure on the mechanical properties of 3D integrated woven spacer composites. Three-point bending, quasi-static compression and low-velocity impact tests were conducted to compare the mechanical responses of 3D woven spacer composites with plain and complex face sheets. The floating yarn segments in complex face sheet could efficiently transfer the stress to neighboring areas and lead to a more balanced stress distribution. The existence of floats thus has positive effect on mechanical properties of composites. On the contrary, plain structure surface was dense and the stress transfer was easily hindered by numerous weaving points, resulting in stress concentration and ultimate premature failure. As a consequence, for surface-dominated properties such as warp-direction bending and impact resistance, 3D integrated woven spacer composites with complex surface is better and should be given priority during industrial applications. In terms of weft-direction bending property and quasi-static compressive performance, which more depend on the structure of core piles, show little difference between the composites with different surfaces.