Exploring mechanical property balance in tufted carbon fabric/epoxy composites

Abstract

The paper details the manufacturing processes involved in the preparation of through-the-thickness reinforced composites via the 'dry preform -tufting -liquid resin injection' route. Samples for mechanical testing were prepared by tufting a 5 harness satin weave carbon fabric in a 3mmx3mm square pitch configuration with a commercial glass or carbon tufting thread, infusing the reinforced preforms with liquid epoxy resin and curing them under moderate pressure. The glass thread reinforcement increases the compression-after-impact strength of a 3.3mm thick carbon fabric laminate by 25%.The accompanying drop-downs in static tensile modulus and strength of the same tufted laminate are below 10%. The presence of tufts is also shown to result in a significant increase in the delamination crack growth resistance of tufted double-cantilever beam specimens and has been quantified for the case of a 6mm thick tufted carbon non-crimped fabric (NCF)/epoxy composite. Keywords (A) 3-dimensional reinforcement, (A) polymer matrix composites (PMCs), (E) preform, tufting.

Improving the Understanding of Tufted Energy Absorbing Sandwich Structures

“…There is also less damage to the preform from the use of multiple needle insertions [9]. Finally, the use of friction to hold the reinforcement in place means that reduced crimping of the fabric takes place, compared to traditional stitching methods, which better maintains the in-plane mechanical properties of the final cured part [10,11]. However, use of the technology is still limited, with understanding of the influence of the manufacturing process on performance [9], as well as the development of suitable design tools [12] still at an early stage.…”

Extruded Monofilament and Multifilament Thermoplastic Stitching Yarns

“…Through-thickness reinforcement is a method of reducing delamination in a laminate composite by increasing its interlaminar properties. This is performed by means of a third directional reinforcement of through-thickness fibres in the z-direction [4]. Through-thickness reinforcement also acts as a mechanical connection between the laminate layers of the composite material prior to the introduction of resin into the material.…”

On-line monitoring of multi-component strain development in a tufting needle using optical fibre Bragg grating sensors

“…Tufting and stitching are suitable for reinforcing dry preforms prior to liquid resin injection and subsequent cure [1,3]. Stitching uses two needles to insert and interlock one or more threads into the preform.…”