Knitting shells in the third dimension

In order to produce textile structures intended for technical applications it is essential to have a full understanding of the geometrical properties and be able to guarantee exact replicas can be manufactured. This paper discusses some of the issues related to the controlled knitting of carbon yarn into three-dimensional 3-D shell shapes and the affect on the structural geometry. The study begins with an examination into the basic issues affecting the knitability of the selected yarn. Health and safety problems are addressed and the resultant carbon yarn was modified to reduce the chances of electrical failure due to conductive fibre fly. Initially two factors were considered relating to the structures geometry, however it was found that a third consideration was required when examining 3-D integrally knitted products. This study identified a maximum variation regarding the stitch length during knitting and devised a methodology to use when considering a yarn for use in 3-D shells. It was found that a two-phase approach was required when producing knitted 3-D shells, part mathematical and part empirical.