Computational & Technology Resources
an online resource for computational,
engineering & technology publications
Civil-Comp Proceedings
ISSN 1759-3433
CCP: 56
Edited by: B.H.V. Topping
Paper IX.6

Validation of an Efficient Computer Model for Spectral Analysis of Offshore Platforms

M. Hartnett and P. Mitchell

Department of Civil Engineering, Trinity College, Dublin, Ireland

Full Bibliographic Reference for this paper
M. Hartnett, P. Mitchell, "Validation of an Efficient Computer Model for Spectral Analysis of Offshore Platforms", in B.H.V. Topping, (Editor), "Advances in Civil and Structural Engineering Computing for Practice", Civil-Comp Press, Edinburgh, UK, pp 359-368, 1998. doi:10.4203/ccp.56.9.6
This paper outlines the background to the development of a frequency domain response model, SPEC, to analysis offshore platforms and the validation of model results. Wave induced loads on the structure are considered to be given by the modified Morison equation. The nonlinear drag term in the Morison equation was linearised in a consistent manner resulting in an equivalent linearised damping matrix. The model was validated in number of different ways as detailed. The eigensolver was compared against the results of industry standard packages and also validated against the first five natural frequencies and mode shapes that were estimated for an existing platform based on a structural monitoring study. Computed spectra of displacements were compared with the results from two separate spectral analyses. Firstly, the spectra of displacements for a simple cantilever were computed for a given input spectrum and compared against the results from a semi-analytical method. Secondly, a model was developed of a large three dimensional lattice platform. The platform was then subject to a random storm event and spectra of displacements computed. The platform was then subjected to the same storm using the software analysis package ASAS and spectra of displacements computed.

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £95 +P&P)