Nonwoven Polyester Interleaving for Toughness Enhancement in Composites
Delamination is one of the primary weaknesses of composite structures. Various researchers have developed techniques to control delamination in laminated structure. One of these techniques is “interleaving,” adding high toughness material to key interfaces in a laminate. This paper studies using polyester veil as a low-cost interleaf alternative to other materials and focuses on a non-woven, polyester spunbond material. Two different thicknesses are considered, DuraSpun 016/090 with thickness of 0.18 mm and DuraSpun 016/120 with thickness of 0.74 mm. Carbon/epoxy composites are manufactured using 2x2 Twill 24”-12k carbon fibers embedded in an epoxy resin, with polyester interleaves at key interfaces. Specimens are fabricated using wet hand layup and cured at room temperature in a vacuum bag. Mode I fracture toughness is measured using the Double Cantilever Beam (DCB) test and Mode II fracture toughness is examined using the End-Notched Flexure (ENF) test. Further evaluation is made using static indentation. Toughness is compared and the resulting fracture surfaces in static indentation are investigated using a scanning electron microscope. Significant improvement is seen in Mode I toughness, as well as smaller improvements in Mode II. The polyester interleaf significant influences the fracture morphology observed in preliminary static indentation tests.
Authors: Adnan A. Gheryani, David C. Fleming, and Ronnal P. Reichard
Conference: SAMPE Seattle 2017