Optimisation of continuous tow-sheared cylinders under uncertainty

The sensitivity to geometric imperfections limits the performance of thin-walled cylinders in compression buckling. The present
work focuses on reducing the imperfection sensitivity of cylinders by using a novel manufacturing technique for composite materials known
as Continuous Tow Shearing (CTS). CTS allows curvilinear steering of carbon fibre tows by shearing the carbon fibre tape, a 50 mm-wide
strip of carbon fibre, that is placed via a robot arm. Steering of the carbon fibre tapes by shearing induces a smooth increase in the thickness
of the tape and these localised thickness build-ups are used as a symmetry-breaking device to limit the impact of imperfections. The localised
thickness build-ups are used to create embedded-stringers and -hoops that tailor the load path within the CTS cylinder. To maximise the
effectiveness of the CTS cylinders, an optimisation framework that accounts for uncertainty is used. The results of the optimisation are
corroborated with a Monte-Carlo analysis. The first optimisation goal is to maximise the thickness-normalised, mass-normalised buckling
load of a CTS cylinder. The second optimisation goal is to minimise mass of a CTS cylinder under a specific load.