Enhancing the bearing strength of woven carbon fibre thermoplastic composites through additive manufacturing

Abstract

This paper examines a novel additive manufacturing (AM) technique for the fabrication of woven multilaminate composites. The printing studies were carried out using nylon coated carbon fibre Tow in the form of a filament. This pathing technique allows for a woven structure to be integrated with features (such as notches) previously only possible through destructive machining processes. In order to evaluate the performance of these printed composites, bearing response studies were carried out. 6 mm holes were routed into a multilaminate woven composite structure, the resulting part’s mechanical performance was then tested and compared with specimens which had been drilled post printing. Specimen were comprised of 9 woven laminates stacked to form a 3.1 mm thick standardised test coupon for single and double shear testing (ASTM D5961). Current industry standard machining techniques result in fibre discontinuity and damage, this results in suboptimal mechanical performance of composite components. These new ‘Tailor Woven’ specimens achieved single shear bearing strengths of up to 214 MPa and double shear bearing strengths of up to 276 MPa. These values represent an increase of 29% and 63% respectively compared with equivalent composites in which the hole had been drilled.