Examining the Effects of Tufting Patterns on Carbon Laminates

The production of Carbon Fibre Reinforced Polymer (CFRP) material is performed by a technique of piling thin layers of carbon fibre material together to a required thickness then joining with a polymer resin.(1) The use of CFRP has moved from only being found in the aerospace and defence industries into automotive, marine, and sporting applications where the need for high performance lightweight components and structures has increased.(2–10) A major concern in the use of CFRP is delamination, this is the propagation of inter-laminar cracks which lead to separation of the laminate layers. This can occur as a result of impacts or machining processes such as drilling. (11) Hocheng et al. reported that the effects of delamination are a decrease in the mechanical strength of the CFRP component, a reduction in the load carrying capacity and an increased likelihood of premature failure.(3) Tufting is a method of reinforcing a composite through its thickness in order to mitigate the effects of delamination. Fig.1 shows the principle of tufting whereupon a material is introduced in the z-direction leaving a loop on the underside and a strand on the upper between each tuft.