No abstract

Drilling and production in deeper water set new requirements to the design of marine risers. In this paper the most common methods of dynamic analysis of such risers are reviewed and discussed with reference to a set of full scale data. The measurements were taken by CONOCO in 1975 on a drilling riser operated from a semisubmersible. A spectral approach is applied in evaluating these data and the results include standard deviations, response, spectra and transfer functions. The quality of the data is found to be generally good. Some doubt is expressed as to the exact conditions at the top support, but it is still considered that important trends are revealed. In the theoretical analysis four different computer programs are investigated, covering six different methods. The programs employ either linearized frequency domain solution or time integration techneques with varying degrees of non-linearities included and for either regular waves or irregular sea. Most of comparisons with measurements are carried out in terms of linearized transfer functions. The validity of this approach is discussed as part of the evaluation of the results.

No abstract

No abstract

No abstract