Low-velocity impact response of hybrid pseudo-woven carbon/epoxy thin composite laminates manufactured via automated fiber placement

To fully automate the manufacturing of hybrid composite laminates, this study investigates the applicability of using Automated Fiber Placement (AFP) manufacturing to produce plain-woven like plies so that manual layup of as-received woven plies is eliminated. Hybrid carbon/epoxy thin composite laminates (∼2 mm thickness) consisting of unidirectional (UD) plies and plain-woven fabric plies are typically laid in two steps. In the first step unidirectional [45/90/-45/0] s plies are placed via AFP, and in the second step, traditional fully woven as-received prepreg fabrics are manually placed onto the UD plies to produce the laminate designated as the fully woven hybrid laminate (FWHL). A modified AFP layup procedure utilizing tow skips is employed in this study to create plain-woven like plies with a pseudo-woven architecture resulting in reduced manufacturing time to produce the laminate designated as the pseudo-woven hybrid laminate (PWHL). The usage of the 24 K tows used in AFP resulted in a 19% increase in areal weight/thickness of the PWHL laminate compared to the 6 K tows in the as-received woven fabric. While the traditional fully woven architecture consists of all tows being woven with undulations, pseudo-woven architecture is composed of both woven and straight non-woven tows. Under low velocity impact, though the damage mechanisms are different, PWHL exhibits comparable, if not, improved damage resistance compared to FWHL. At 10 J/mm (impact energy normalized by thickness), PWHL exhibits 27 % higher elastic energy compared to FWHL, demonstrating the feasibility of using AFP for producing plain-woven like plies and hybrid composite layups more efficiently.