Published online by Cambridge University Press: 04 July 2016
An interactive computer programme, based on linear-elastic laminated plate theory, is used to study the effect of lay-up geometry on first ply failure loads. A maximum allowable strain failure criterion is used and a number of design problems are considered where searches are made for optimum lay-up configurations for typical carbon fibre reinforced plastic properties. The relative weakness of this material in tension across the fibres, is found to have a significant effect on first ply failure loads. An optimisation technique based on principal load directions is introduced and compared with the familiar 0/90/±45 lay-up configuration.