Proceedings home preface contents authors keywords copyright reference ©2012 Civil-Comp Ltd				Paper 267 A Commentary on Improving the Design Rules for Thin Aluminium Shell Structures J.W. Bull Department of Civil Engineering, School of Engineering and Design, Brunel University, Uxbridge, United Kingdom Keywords: aluminium design, design rules, Eurocode 3, Eurocode 9, shell buckling, shell theory. full paper (pdf) - reference The complexity of the available design methods for thin aluminium shells is simplified in EN1999-1-5 [1]. However in EN1999-1-5 there are eight types of shell analysis and a commentary on where each type gives the most accurate results and in what order of precedence each type is used is needed. EN1999-1-5 is heavily reliant upon the principles of steel thin shell design given in EN1993-1-6 with additional specific design studies and research formulated for aluminium [1,2]. However the behaviour of aluminium is different to steel; aluminium shells are more susceptible to buckling, fatigue, strain hardening, imperfections and welding. Further there is strongly different behaviour in the transition region between the elastic and the plastic range imperfections and post buckling performance recovery. Also thin aluminium shells are particularly susceptible to material and geometrical imperfections. Additionally EN1999-1-5 cannot be used without persistent reference to EN1993-1-6 [1,2]. This persistent recourse in EN1999-1-5 to EN1993-1-6 can lead to designers being misinformed about the design process, or making incorrect assumptions when deciding which section of which Eurocode is appropriate and which material is being use [1,2]. The European Commission sent to CEN a programming mandate concerning the Structural Eurocodes [3]. The mandate included reference to the further development of EN1999-1-5 and said further guidance was needed to make EN1999-1-5 easier for practical application [1,3]. Previous research by the author has identified ways of improving the use of EN1999-1-5 [4,5]. The present paper indicates ways in which the EN1999-1-6 requirements for shell design need to be incorporated into EN1999-1-5 to reduce confusion when designing thin aluminium shells and to help ensure computer resources use only the appropriate analysis methods. References 1 BS EN 1999-1-5:2007, "Eurocode 9 - Design of aluminium structures, Part 1-5 Shell structures", BSI, London, UK, 2007. 2 BS EN 1993-1-6:2007, "Eurocode 3 - Design of steel structures, Part 1-6 Strength and stability of shell structures", BSI, London, UK, 2007. 3 Mandate M/466, "Programming mandate address to CEN in the field of the Structural Eurocodes", Brussels, 23th March 2010. 4 J.W. Bull, O. Gurav, C.H. Woodford, "A designer's perspective of using finite element methods for the design of aluminium shells to Eurocode 9", in B.H.V. Topping, L.F. Costa Neves, R.C. Barros, (Editors), "Trends in Civil and Structural Engineering Computing", Saxe Coburg Publications, 187-208, 2009. doi:10.4203/csets.22.9 5 J.W. Bull, D.C. Gibson, "Buckling analysis results for an aluminium shell designed to Eurocode 9 Part 1-5", in B.H.V. Topping, Y. Tsompanakis, (Editors), "Proceedings of the Thirteenth International Conference on Civil, Structural and Environmental Engineering Computing", Civil-Comp Press, Stirlingshire, United Kingdom, paper 161, 2011. doi:10.4203/ccp.96.161