Application of optimisation methods to the design of high performance composite pipelines

This paper describes a contribution to the research carried out by a consortium under the BRITE/EURAM programme of the EC on the application of optimisation techniques to problems of engineering design using composite materials; one area addressed is that of gas transmission pipelines. The candidate pipeline is filament wound using a glass reinforced epoxy (GRE) resin and is designed for a gas transmission line with an operational pressure of 70 bar. A safety factor of 4.5, approximately, is used. An innovative coil-lock joint is shown to successfully perform the connection between pipeline sections. The main problem is that the highest stresses occur at the transition between pipe and joint. Optimisation software is used as a tool for improving the pipeline design. The optimisation is applied to the pipeline in the area of the joint. The objective function is to minimise the weight of the pipeline. Pipeline to joint transition geometries, as well as overall pipe thickness are optimised. Maximum structural stresses are used as constraints in the optimisation process. Results show a significant reduction in peak stresses at pipeline to joint transitions and a minimisation of pipeline mass. (C) 2003 Elsevier Science B.V. All rights reserved.