Co-Cured Structural Steel-Composite Joints for Deck to Superstructure Connections

Abstract

Through experimental and numerical analyses this paper proposes to improve the confidence in the use of steel-composite joints through understanding of their performance for application as the attachment of a composite superstructure to a steel hull envelope. This is achieved through investigation of the static and fatigue performance of a typical connection, the influence of hygrothermal ageing, the numerical prediction of the failure path within the connection subject to static loading and the optimisation of the connection to increase performance. The results show that the strength and durability of the proposed joint is sufficient to withstand the expected applied loads to the superstructure and that the exposure to moisture does not influence the performance even after 2 years of accelerated ageing. The numerical method proposed accurately predicted the path of failure within the joint and also predicted the response of the joint during failure using a novel approach of modelling the failure of the adhesive material. The use of genetic algorithms provided an efficient way of searching the steel-composite design space to minimise the main design driver, weight. This research provides significant confidence in the performance of the steel-composite connection and its application to structures such as helicopter hangars on naval and commercial vessels.