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Journal of Applied Mathematics
Volume 2012, Article ID 134896, 14 pages
Research Article

An Analytical Approach to the Analysis of Inhomogeneous Pipes under External Pressure

Department of Structural Engineering, University of Naples Federico II, via Claudio 21, 80125 Naples, Italy

Received 19 February 2012; Revised 6 May 2012; Accepted 7 May 2012

Academic Editor: Ioannis K. Chatjigeorgiou

Copyright © 2012 Massimiliano Fraldi and Federico Guarracino. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Pipes for deep-water applications possess a diameter-to-thickness ratio in a region where failure is dominated by both instability and plastic collapse. This implies that prior to failure the compressive yield strength of the material must be exceeded, followed by ovalisation and further local yielding. This paper presents an investigation into the mechanics of this specific problem and develops an analytical approach that accounts for the effects of geometrical and material data on the collapse pressure of inhomogeneous rings under external hydrostatic pressure. The analytical expressions have been correlated to numerical and experimental test data, proving their accuracy.