REFERENCES
15
steels and the reliability of several types of high-strength, light-weight synthetic
rope mooring lines.
Modeling and Analysis
Once the site, the environmental load conditions, and the preliminary structural design are determined, a mathematical model of the structure is formulated, and computer-aided analyses are performed to détermine the overall motion, the critical stresses, and the reliability of the design. The fondamental
mechanics of fatigue and fracture were reviewed by Petroski (1984), who discussed fatigue failures that hâve occurred at the welded tubular joints, which
can be subjected to millions of loading cycles during a structure’s lifetime. It
is particularly important to include fatigue in the structural reliability analysis.
Novel and improved methodology for reliability assessment of offshore structural
welded joints, with applications to jackup rigs, was discussed by Etube (2001).
Computer graphies and finite element methods of structural analysis that aid
in this design process are continually being improved. Structural optimization,
least weight criteria, nonlinear dynamics, fluid-structure-soil dynamic interactions, and statistical methods are being added and refined in the mathematical
models. The aims are to achieve more accurate représentations for structural
dynamic behavior and improve the prédictions of structural lifetimes. See Buchholt (1997) and Jin and Bea (2000).
Experimental Evaluations
Before a structure is installed offshore, extensive tests are made on its
component materials and also on its overall dynamic behavior using scaleddown laboratory models with simulated environmental load conditions. Présent
laboratory-scale efforts are focused on two issues: fluid-structural load interactions, especially the effects of fluid vortices on structural motion; and the
mechanics of structural-soil foundation interactions.
Once installed in the field, the structure may be instrumented for a period of
time to détermine whether its behavior under a variety of natural forces has been
accurately predicted by the mathematical models and analyses used in its design.
Such data are useful for future similar designs. In addition, for platforms, buoys,
and pipeline Systems nearing the end of their lifetimes, frequent inspection and
maintenance are required to assure continuing performance. Improvements are
being made in the computer Systems used for the retrieval, storage, and analysis
of large amounts of data from both laboratory scale and field tests of offshore
structural Systems.
REFERENCES
Adrezin, R., Bar-Avi, P. and Benaroya, H., Dynamic Response of Compilant Offshore
Structures—Review, Journal of Aerospace Engineering, October, 114-131, 1996.
Baar, J. J. M., Heyl, C. N., and Rodenbusch, G., Extrême Responses of Turret
Moored Tankers, Proceedings of the Offshore Technology Conférence, OTC12147, 2000.
15
steels and the reliability of several types of high-strength, light-weight synthetic
rope mooring lines.
Modeling and Analysis
Once the site, the environmental load conditions, and the preliminary structural design are determined, a mathematical model of the structure is formulated, and computer-aided analyses are performed to détermine the overall motion, the critical stresses, and the reliability of the design. The fondamental
mechanics of fatigue and fracture were reviewed by Petroski (1984), who discussed fatigue failures that hâve occurred at the welded tubular joints, which
can be subjected to millions of loading cycles during a structure’s lifetime. It
is particularly important to include fatigue in the structural reliability analysis.
Novel and improved methodology for reliability assessment of offshore structural
welded joints, with applications to jackup rigs, was discussed by Etube (2001).
Computer graphies and finite element methods of structural analysis that aid
in this design process are continually being improved. Structural optimization,
least weight criteria, nonlinear dynamics, fluid-structure-soil dynamic interactions, and statistical methods are being added and refined in the mathematical
models. The aims are to achieve more accurate représentations for structural
dynamic behavior and improve the prédictions of structural lifetimes. See Buchholt (1997) and Jin and Bea (2000).
Experimental Evaluations
Before a structure is installed offshore, extensive tests are made on its
component materials and also on its overall dynamic behavior using scaleddown laboratory models with simulated environmental load conditions. Présent
laboratory-scale efforts are focused on two issues: fluid-structural load interactions, especially the effects of fluid vortices on structural motion; and the
mechanics of structural-soil foundation interactions.
Once installed in the field, the structure may be instrumented for a period of
time to détermine whether its behavior under a variety of natural forces has been
accurately predicted by the mathematical models and analyses used in its design.
Such data are useful for future similar designs. In addition, for platforms, buoys,
and pipeline Systems nearing the end of their lifetimes, frequent inspection and
maintenance are required to assure continuing performance. Improvements are
being made in the computer Systems used for the retrieval, storage, and analysis
of large amounts of data from both laboratory scale and field tests of offshore
structural Systems.
REFERENCES
Adrezin, R., Bar-Avi, P. and Benaroya, H., Dynamic Response of Compilant Offshore
Structures—Review, Journal of Aerospace Engineering, October, 114-131, 1996.
Baar, J. J. M., Heyl, C. N., and Rodenbusch, G., Extrême Responses of Turret
Moored Tankers, Proceedings of the Offshore Technology Conférence, OTC12147, 2000.