Direct Methods of Plasticity in Aluminium Frames Accounting for Eurocode 9 Failure Criteria

Abstract:

Metal structures, given their broad plastic deformation capacity, have been often at the core of research for the evaluation of the post elastic behavior via the direct methods of plasticity. Limit and shakedown analysis were often exploited to determine the plastic collapse load capacity, as they provide advantages in terms of computational robustness in comparison with incremental non-linear analysis. The aforementioned approach has been widely and effectively applied for steel structures, characterized by rigid-plastic behavior. Υet in the case of aluminium structures, there are special parameters to be considered, as they exhibit a relationship of round-house type, whose trend cannot be interpreted through the classic elastic-perfectly plastic material law idealization.The present paper aims to develop a limit and shakedown analysis formulation suitable for the safety assessment of 3D aluminium frame structures against plastic collapse. Research yielded the proposed two-surface methodology in the framework of stress resultant plasticity, which is capable of estimating the plastic collapse limit state of real-life aluminium frames, incorporating Eurocode 9 codified failure criteria and limited kinematic hardening. A numerical example of a 3D frame is realized utilizing the finite element method and the 3-node Timoshenko column-beam element, in order to showcase the proposed methodology and validate the influence of hardening effect.

• Periodical: Key Engineering Materials (Volume 710)
• Pages: 415-420
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.710.415
• Online since: September 2016
• Authors: Alexios T. Ampatzis, Vasileios G. Psomiadis, Evangelos Efthymiou*
• Keywords: Aluminium Alloys, Computational Analysis, Direct Methods of Plasticity, Eurocode 9 Failure Criteria, Post-Elastic Behavior

References

[1] Mazzolani, F. M. 2006. Structural Applications of Aluminium in Civil Engineering, Struct Eng Int. 16 (2006) 280-285.

[2] F.M. Mazzolani, Aluminium Alloy Structures, second edition, London UK, Chapman & Hall, (1995).

[3] Mazzolani, F. M., Mandara, A., Langseth, M. Plastic design of aluminium members according to EC9, Proc. of the 4th International Conference on Light-Weight Steel and Aluminium Structures ICSAS '99, 20-23 June 1999, Espoo, Finland, Mäkeläinen, P., Hassinen, P. (Eds), Elsevier Science Ltd, 1999, pp.457-464.

DOI: 10.1016/b978-008043014-0/50156-6

[4] De Matteis, G., Landolfo, R., Manganiello, M., Mazzolani, F. M. 2004. Inelastic behaviour of I-shaped aluminium beams: numerical analysis and cross-sectional classification, Comput Struct. 82 (2004) 2157-2171.

DOI: 10.1016/j.compstruc.2004.03.071

[5] Manganiello, M., De Matteis, G. Landolfo, R. 2006. Inelastic flexural strength of aluminium alloy structures, Eng Struct. 28 (2006) 593-608.

DOI: 10.1016/j.engstruct.2005.09.014

[6] C.D. Bisbos., A.T. Ampatzis, Shakedown analysis of spatial frames with parameterized load domain, Eng Struct. 11 (2008) 3119-3128.

DOI: 10.1016/j.engstruct.2008.04.022

[7] K.D. Nikolaou, M-A.A. Skordeli, C.D. Bisbos, Limit analysis of aluminium frames via approximate ellipsoidal yield surfaces, in: Proc. of 10th HSTAM Int. Congress on Mechanics, Chania, Greece, May (2013).

DOI: 10.1016/j.engstruct.2010.02.004

[8] A. Ponter. A general shakedown theorem for elastic plastic bodies with work hardening, in: Proc. SMIRT-3, paper L5/2, (1975).

[9] J-W. Simon, D. Weichert, Shakedown analysis of engineering structures with limited kinematical hardening, Int J Solids Struct. 49 (2012) 2177–2186.

DOI: 10.1016/j.ijsolstr.2012.04.039

[10] CEN/TC250/SC9, EN 1999-Eurocode 9: Design of aluminium structures- Part 1-1: General structural rules, CEN-European Committee for Standardisation, Brussels, Belgium, (2007).

[11] CEN/TC250/SC1, EN 1991-Eurocode 1: Actions on structures- Part 1-1: General actions , CEN-European Committee for Standardisation, Brussels, Belgium, (2002).

[12] MOSEK ApS., The MOSEK optimization toolbox for MATLAB manual. Version 7. 1 (Revision 28), 2015, http: /docs. mosek. com/7. 1/toolbox/index. html.

[13] MATLAB R2015, The MathWorks, Inc., Natick, Massachusetts, United States.