Interactive Response Behavior of Tendon Groups
Past students include: Oriol R. Rijken, John van de Lindt (PhD students), Scott Chitwood, Jason Gage (MS students), and Ron Lee (MS student)
Current students include: Qi He, Pierre Liagre (PhD student), Aaron Oswalt and Monte Conner (MS students)
On deepwater TLP and SPAR platforms tendons and risers are commonly arranged in groups or bundles for practical reasons. Their hydrodynamic excitation and dynamic response behavior is not well understood and thus cannot be accurately modeled in current design practice. Thus more basic research identifying mechanism and characteristic behavior are needed before better predictive models can be developed.
The development of new predictive models for slender members used in deepwater platforms is one important aspect of the fluid/structure thrust area. It also impacts the materials/structure thrust area dealing specifically with composite marine riser design. Motions coupled with the deepwater platform hulls will be examined as part of the "theme structure" studies.
A series of experiments reflecting both advances in understanding of excitation and response behavior and improved measurement and modeling techniques has been unfolding. A series of experiments were performed in the Spring of 1996 to address technical questions raised in the 1994 tests and also to examine a generic TLP tendon configuration. Statistical characterization and probabilistic techniques have been utilized to examine the quality data sets obtained for distorted and undistorted models in a wide range of design seaways. Predictive models for collision and interference phenomena are under development which includes fatigue and reliability estimates. Investigation of relevant SPAR data which combine hull and tendon/riser motions are being utilized in this investigation. New data from a mini TLP experiment planned for the Spring of 1997 will also be studied.
Basic research and applied research by Dr. Vandiver (MIT) and Dr. Allen (Shell) are quite relevant to this investigation. Earlier studies by Dr. Sarpkaya and Heideman (Exxon) are also noted.
Any advances in predictive models will require a better understanding of this fluid/structure interaction phenomena. No accurate model for collision of tendons or risers arranged in clusters is currently available.
October 1994 to September 1998
The results to date can be found in several OTRC reports and a number of scholarly publications which have been published or are in press.
To date the major means of technology transfer has been through OTRC reports and scholarly publications. Additional lectures at STATOIL and NTH have been given in the past two years and more are planned as is more collaboration with faculty at NTH.