文档介绍：ARTICLE IN PRESS
Journal of Sound and Vibration 329 (2010) 43–55
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Journal of Sound and Vibration
journal homepage: ate/jsvi
The effect of higher harmonic forces on fatigue life of marine risers
Y. Modarres-Sadeghi Ã, H. Mukundan, . Dahl, . Hover, . Triantafyllou
Department of Mechanical Engineering, Massachusetts Institute of Technology Cambridge, MA 02139, USA
article info abstract
Article history: Higher harmonic responses measured in flexible riser model tests conducted within the
Received 27 October 2008 Norwegian Deepwater Programme (NDP) are studied to evaluate the effect of higher
Received in revised form harmonics of force on the fatigue life of risers. A large third-harmonic contribution and
4 May 2009 sometimes a fifth-harmonic are observed for the majority of test cases. Since existing
Accepted 24 July 2009
methods of fatigue life estimation account for the effect of hydrodynamic forces only at
Handling Editor: . Metrikine
Available online 9 October 2009 the frequency of vortex shedding, a new methodology is introduced which takes into
account the influence of the higher ponents: First, a new response
reconstruction technique is used to reconstruct the entire span-wise riser motion in
both the cross-flow and in-line directions based on measurements at specific points
along the length. Then, a force database obtained from forced in-line and cross-flow
motions of rigid cylinders is used to estimate the higher ponents of the
force along the entire riser length. A significant decrease in fatigue life is obtained when
the higher ponents of the fluid forces are considered.
& 2009 Elsevier Ltd. All rights reserved.
1. Introduction
The vortex-induced vibration (VIV) of long, flexible cylinders, such as marine risers and mooring lines, constitutes an
important problem in deep water oil exploration and production. In particular, sustained vibration of risers can lead to
structural