A methodology to design fibre reinforced laminated composite structures for maximum strength

Abstract

A procedure to select the optimal fibre orientations and determine the maximum load carrying capacity of symmetrically laminated fibre reinforced composite structures is described. Cylindrical shells subject to combinations of torque and in-plane forces are used to illustrate the methodology and are optimally designed for maximum strength. Torque tubes are generally used as control mechanisms, for example, in the tail fins of aircraft. The finite element method, based on Mindlin plate and shell theory, is used in this application in conjunction with an optimisation routine in order to obtain the optimal designs. The methodology consists of two stages; the objective of the first is to maximise the strength of the cylindrical shells by determining the fibre orientations optimally while the objective of the second stage is to maximise the in-plane compression loading subject to a failure criterion. The effect of different shell aspect ratios, wall thickness, layer numbers and boundary conditions on the results is investigated.