Course objectives:
The course will give a brief overview of different types of ocean structures that are deployed in sea for exploiting oil, gas and minerals. While fundamentals of structural dynamics are discussed, detailed mathematical modeling of ocean structures and their dynamic analysis under waves, wind and current are highlighted with special emphasis to fluid-structure interaction. Introduction to stochastic dynamics of ocean structures is also discussed with lot of tutorials and sample papers that shall intuit self-learning through the course. Focus is on the explanation of fundamental concepts as addressed to graduate students.

Course contents:

Module 1
Introduction to different types of offshore structures- Environmental forces- structural action of ocean structures- fluid-structure interaction- Introduction to structural dynamics- Characteristics of single degree-of-freedom model - Methods of writing equation of motion- comparison of methods- Free and forced vibration of single degree-of-freedom systems- Undamped and damped systems- Formulation of equation of motion- examples- Coulomb damping- comparison of damped and undamped forced vibration- response build up-- nature and comparison- Numerical problems in single degree-of-freedom systems- Two degree-of-freedom systems- formulation of equation of motion- eigenvalues and eigenvectors- Orthogonality of modes- Study of multi degrees-of-freedom systems- Equations of motion- Natural frequencies and mode shapes- Stodla, Rayleigh-Ritz and influence coefficient methods- Matrix methods for dynamic analysis- Eigen solution- Modal analysis. Module 2
Types of offshore structures- structural action of offshore structures- form based development- Fixed type offshore structure- dynamic analysis using software- comparison of responses of fixed type offshore structures- Articulated towers- single leg and multi-legged towers- Problem formulation and solution using Iterative frequency domain method- Merits of different structural forms in dynamics' perspective- single column structure- Multi-legged articulated towers- formulation of equation of motion- dynamic characteristics of Mass, stiffness and damping- Dynamic analysis of articulated Multi-legged articulated towers- response control of MLAT using tuned mass dampers- Tension Leg platforms- conceptual development and geometric optimization- Development of Mass, stiffness and damping matrices of TLP from first principles- nonlinearities associated with the problem-Dynamic analysis of offshore TLPs under earthquakes in the presence of waves- dynamic tether tension variations caused by vertical seismic excitations- - Fluid structure interaction- inference of offshore platforms in flow regime- Estimate of damping in offshore structures- Rayleigh damping, classical damping, Caughey damping- comparison and suitability to offshore structures - Damping by mode superposition- Numerical method to solve equation of motion in time domain- Newmark's beta method- Future generation offshore structures- Buoyant Leg structures- Offshore triceratops- Formulation of the problem- Development of Mass, stiffness and damping matrices for triceratops- Numerical modeling using software- Experimental studies on dynamic response of offshore triceratops- comparison of analytical, numerical and experimental studies on offshore triceratops- Module 3
Introduction to stochastic dynamics of ocean structures- Stationary process- stochastic process- Random environmental processes-Response spectrum- Narrow band process- return period- fatigue prediction- mal response method- modal mass contribution- truncation of higher modes and missing mass correction- Duhamel's integral.

Module No.

Topics

No. of lectures

1

Introduction to different types of ocean structures

Development of structural forms for deep and ultra-deep waters

Environmental forces

structural action of ocean structures

fluid-structure interaction

Introduction to structural dynamics

Characteristics of single degree-of-freedom model

Methods of writing equation of motion

comparison of methods-

Free and forced vibration of single degree-of-freedom systems

Undamped and damped systems

Formulation of equation of motion

examples

Coulomb damping

comparison of damped and undamped forced vibration - response build up

Numerical problems in single degree-of-freedom systems

Two degrees-of-freedom systems

Formulation of equation of motion

Eigenvalues and eigenvectors

Orthogonality of modes

Study of multi degrees-of-freedom systems

Equations of motion

Natural frequencies and mode shapes

Stodla, Rayleigh-Ritz and influence coefficient methods, Dunkerley

Matrix methods for dynamic analysis

Eigen solution

Modal analysis

25

2

Structural action of offshore structures

Types of offshore structures based on the geometric form

Development of structural form for deep waters

Fluid-structure interaction

Dynamic analysis of offshore jacket platforms

steps of analysis using software

Dynamic analysis of articulated towers

Iterative frequency domain

Multi-legged articulated towers

Response control of multi-legged articulated towers using tuned mass dampers

Experimental and analytical studies on MLAT

Development of Tension Leg Platforms and geometric optimization

Dynamic analyses of TLPs

Development of Mass, stiffness and damping matrices of TLP from first principles

Dynamic analysis methodology of offshore structures under earthquakes

TLPs under seismic excitation

Development of new generation offshore structures

Buoyant Leg Structures and offshore triceratops

Numerical modeling of offshore triceratops using software

Comparison of experimental, analytical and numerical studies on offshore triceratops

Estimate of damping: Classical damping, Rayleigh and Caughey

Damping by mode superposition

Analytical technique to solve equation of motion using in Newmarks Beta method

17

3

Introduction to stochastic dynamics of ocean structures

Random environmental processes

Stationary process

Response spectrum

Narrow band process

Return period

Fatigue prediction

Modal response method

Modal mass contribution

Missing mass correction, Example problems

Duhamel's integrals

7

Total

49 lectures

a) Books and Executive reports

Anil K. Chopra. 2003. Dynamics of structures: Theory and applications to earthquake Engineering: Pearson Education, Singapore.

Arvid Naess and Torgeir MOan. 2013. Stochastic dynamics of marine structures, Cambridge University Press, New York, USA.

Chakrabarti, S. K. 1987. Hydrodynamics of Offshore Structures: Computational Mechanics.

Chakrabarti, S. K. 1990. Non-linear method in offshore engineering, Elsevier Science Publisher, The Netherlands.

Chakrabarti, S. K. 1994.Offshore Structure Modeling: World Scientific.

Clauss, G. T. et al. 1992. Offshore Structures, Vol 1 - Conceptual Design and Hydromechanics: Springer, London.

Dawson, T. H., 1983. Offshore Structural Engineering: Prentice-Hall Inc.

Gerwick, B.C.Jr. 1986. Construction of Offshore Structures: John Wiley, New York.

Graff, W.J. 1981. Introduction to offshore structures: Design, fabrication and installation: Gulf Publishing Co, Tokyo.

James F. Wilson 1984. Dynamics of offshore structuresMather, A. 2000. Offshore Engineering: an Introduction, 2nd edn: Witherby

Patel, M. H., 1989. Dynamics of offshore structures: Butterworths, London.

Sadehi, K. 1989. Design and analysis of Marine structures: Khajeh Nasirroddin Tsi University of Technology, Tehran, Iran.

Sarpkaya, T. and Isaacson, M. 1981. Mechanics of Wave Forces on Offshore Structures: Van Nostrand Reinhold.

Srinivasan Chandrasekaran and Subrata Kumar Bhattacharyya (2012). Analysis and Design of Offshore Structures with illustrated examples. Human Resource Development Center for Offshore and Plant Engineering (HOPE Center), Changwon National University Press, Republic of Korea ISBN: 978-89-963915-5-5.

b) Research papers suggested for additional reading

Ahsan Kareem. 1985. Wind induced response analysis of Tension Leg Platforms. J. of Structural Eng. 111(1): 37-55.

Anagnostopoulos, S.A. 1982. Dynamic Response of Offshore Structures to Extreme Waves including Fluid - Structure Interaction. Engr. Structures, 4: 179-185.

Bar Avi. P 1999. Nonlinear Dynamic Response of a Tension Leg Platform, J. of Offshore Mechanics and Arctic Eng, 121: 219-226.

Bea, R.G. Xu, T., Stear, J. and Ramas, R. 1999. Wave Forces on Decks of Offshore Platforms. J. Waterway, Port, Coastal and Ocean Engineering, 125(3):136-144.

Bhattacharyya. S. K., Sreekumar. S and Idichandy. V. G. 2003. Coupled dynamics of Sea Star mini tension leg platform. Ocean Eng, 30: 709-737.

Boaghe, O.M., Billings, S.A., Stansby, P.K. 1998. Spectral Analysis for Non-Linear Wave Forces. J. Applied Ocean Research, 20: 199-212.

Booton. M., Joglekar. N and Deb. M 1987. The effect of tether damage on Tension Leg Platform Dynamics. J. of Offshore Mechanics and Arctic Eng, 109: 186-192.

Burrows, R., Tickell, R.G., Hames, D. and Najafian, G. 1992. Morison Wave Forces Co-efficient for Application to Random Seas. J. Applied Ocean Research, 19: 183-199.

Chakrabarti, S. K. 1971. Nondeterministic Analysis of Offshore Structures, J. Engineering Mechanics, ASCE, 97.

Chandrasekaran, S and Jain, A.K. 2002a. Dynamic behavior of Square and Triangular TLPs under Regular Wave Loads. Ocean Engineering, 29(3): 279-315.

Chandrasekaran. S and Jain. A. K. 2002b. Triangular configuration Tension leg platform behaviour under random sea wave loads, Ocean Eng. 29(13): 1895-1928.

Chandrasekaran, S., Jain, A.K., Chandak, N. R. 2004. Influence of Hydrodynamic Coefficients in the Response behavior of Triangular TLPs in Regular Waves. Ocean Engineering, 31: 2319-2342.

Chandrasekaran. S and Jain. A. K. 2004a. Aerodynamic behavior of offshore triangular Tension Leg Platforms, Proc. of ISOPE, Toulon, France, 564-569.

Chandrasekaran. S, Jain. A. K, Chandak. N. R. 2004b. Influence of hydrodynamic coefficients in the response behavior of triangular TLPs in regular waves, Ocean Eng. 31(320): 2319-2342.

Chandrasekaran. S, Jain, A.K. and Chandak. N.R. 2006a. Seismic analysis of offshore triangular tension leg platforms. International J. of Structural Stability and Dynamics. 6(1): 97-120.

Chandrasekaran, S., Chandak, N. R and Gupta Anupam 2006b. Stability analysis of TLP tethers. Ocean Eng. 33(3): 471-482.

Chandrasekaran. S, Jain. A. K, Chandak. N. R 2007a. Response behavior of triangular tension leg platforms under regular waves using Stokes nonlinear wave theory. J. of waterway, port, coastal and ocean Eng., ASCE. 133(3): 230-237.

Chandrasekaran. S, Jain. A. K, Gupta. A and Srivastava. A 2007b. Response behavior of triangular tension leg platforms under impact loading, Ocean Eng.,34: 45-53.

Chandrasekaran. S, Abhishek Sharma and Shivam Srivastava 2007c. Offshore triangular TLP behavior using dynamic Morison equation. J. of Structural Eng. 34(4): 291-296.

Chandrasekaran. S, Gaurav 2008. Offshore triangular tension leg platform earthquake motion analysis under distinctly high sea waves. J. of Ships and Offshore Structures. 3(3): 173-184.

Chen. X, Ding . Y, Zhang. J, Liagre. P, Neidzwecki and Teigen. P 2006. Coupled dynamic analysis of a mini TLP: Comparison with measurements, Ocean Eng. 33: 93-117.

Chuel-Hyun Kim, Chang-HO Lee and Ja-Sam Goo 2007. A dynamic response analysis of tension leg platforms including hydrodynamic interaction in regular waves. Ocean Eng. 34: 1680-1689.

Clauss, G.F., Birk, L. 1996. Hydrodynamic Shape Optimization of Large Offshore Structures. J. Applied Ocean Research, 18:157-171.

Emil Simiu and Stefan D. Leigh 1984. Turbulent Wind and Tension Leg Platform Surge. J. of Structural Eng. 110(4): 785-802.

Ertas. A and Eskwaro-Osire. S 1991. Effect of Damping and Wave Parameters on Offshore Structure under Random Excitation. Nonlinear Dynamics, 2: 119-136.

Ertas. A, Lee. J-H 1989. Stochastic Response of Tension Leg Platform to Wave and Current Forces. J. of Energy Resources Technology,111: 221-230.

Han S. Choi and Jack Y. K. Lou 1991. Nonlinear behavior of an articulated offshore loading platform. Applied Ocean Research, 13(2): 63-74.

Haritos. N 1985. Modeling the response of Tension Leg Platforms to the effects of wind using simulated traces. Mathematics and computers in simulation. 27:231-240.

Hsien Hua Lee and Wang Pei-Wen 2000. Dynamic behavior of tension-leg platform with net cage system subjected to wave forces. Ocean Eng. 28: 179-200.

Inyeol Paik and Jose M. Roesset 1996. Use of Quadratic Transfer Functions to Predict Response of Tension Leg Platforms. J. of Eng. Mechanics. 122(9): 882-889.

Issacson, M., Det St. Q. 1982. Non-Linear Wave Effects on Fixed and Floating Bodies. J. Fluid Mechanics, 120: 267-281.

Jefferys. E. R. and Patel. M. H 1982. Dynamic Analysis Models of Tension Leg Platforms, J. of energy Resources Technology. 104: 217- 223.

Kareem, A. 1983. Nonlinear dynamic analysis of compliant offshore platforms subjected to fluctuating winds. J. of wind Eng. and Industrial aerodynamics. 14: 345-356.

Kareem, A. and Datton, C. 1982. Dynamic effects of wind on TLP. Proc. of Offshore Technology Conference. No. 4229(1):749-757.

Kareem, A., Lu, P.C., Finnigan, T.D. and Liu, S.L.V. 1986. A wind tunnel investigation of aerodynamic loads on a typical TLP. Proc. of Offshore Technology Conference, No. 5173: 187-197.

Kareem. A and Zhao. J 1994. Analysis of Non-Gaussian Surge Response of Tension Leg Platforms Under Wind Loads, J. of Offshore Mechanics and Arctic Eng. 116: 13-144.

Kobayashi. M, Shimada. K and Fujihira. T 1987. Study on Dynamic Responses of a TLP in Waves. J. of Offshore Mechanics and Arctic Eng. 109: 61-66.

Kurian. V. J., Gasim. M. A., Narayan. S. P and Kalaikumar. V 2008. Parametric Study of TLPs subjected to Random Waves. International Conference on Construction and Building Technology, 16-20 June, Kuala Lumpur, Malaysia. 19: 213-222.

Low. Y. M 2009. Frequency domain analysis of a tension leg platform with statistical linearization of the tendon restoring forces. Marine structures, 22: 480-503.

Mekha B.Basim, Philip Johnson. C, Roesset. M Jose. 1996. Implication of Tendon Modeling on Nonlinear Response of TLP. J. of Structural Eng. 122(2): 142-149.

Moe, G. and Verley, R.L.P. 1980. Hydrodynamic damping of offshore structures in wave and currents. Offshore Technology Conference, 12th Annual OTC, Houston, Texas, 37-44.

Morison, J.R., O'Brien, M.P., Johanson, J.W., and Shaaf, S.A. 1950. The Forces Exerted by Surface Waves on Pile. Transactions AMIE, 189: 149-154.

Nagamani. K and Ganapathy. C 2000. The dynamic response of a three leg articulate tower. Ocean Eng. 27: 1455-1471.

Nazrul Islam and Suhail Ahmad 2003. Nonlinear Seismic Response of Articulated Offshore Tower. Defence Science J. 53(1): 105-113.

Nordgren. R. P. 1987. Analysis of high frequency vibration of tension leg platforms. J. of offshore mechanics and arctic Eng. 109: 119-125.

Oriol .R.Rijken,John M.Niedzwecki. 1991. A knowledge Base approach to the design of Tension leg platform. Offshore technology center, 24-100.

S. Dunkerley. 1894. On the whirling and vibration of shafts. Phil. Trans. Royal Society- PartA, 185(1): 279-360.

Sadehi, K. 2007. Offshore and petroleum platforms for Cyprus oil/Gas fields. GAU J. Soc & Appl. Sci., 2(4), 1-16.

Spanos P. D and Agarwal V. K 1984. Response of a Simple Tension Leg Platform Model to Wave Forces Calculated at Displaced Position. J. of Energy Resources Technology. 106: 437-443.

Srinivasan Chandrasekaran, Bhaskar K., Lino Harilal and Brijit, R. 2010b. Dynamic response behavior of multi-legged articulated tower with and without TMD, Proc. International Conf. of Marine Tech. MARTEC-2010., 11-12 Dec, Dhaka, Bangladesh, p.131-136.

Srinivasan Chandrasekaran, Bhaskar, K. and Muhammed Hashim. 2010a. Experimental study on dynamic response behavior of multi-legged articulated tower. Proc. 29th International Conf. on Ocean, Offshore and Arctic Engg, OMAE 2010, 6-11th June, Shanghai, China.

Srinivasan Chandrasekaran, R. Sundaravadivelu, R. Pannerselvam and S. Madhuri 2011. Experimental investigations of offshore triceratops under regular waves, Proc. 30th International Conf. on Ocean, Offshore and Arctic Engg, OMAE 2011, 19-24th June, Rotterdam, The Netherlands.

Stoke's, G. G., 1880. On the Theory of Oscillatory Waves. Mathematics and Physics Papers, 1: 225-228.

Tabeshpour. M. R, Golafshani. A. A and Seif. M. S 2006. Comprehensive study on the results of tension leg platform responses in random sea. J. of Zhejiang University Science. 7(8): 1305-1317.

Vannucci. P 1996. Simplified optimal design of tension leg platform TLP. Structural optimization. 12: 265-268.

White. N. Charles, Copple. W. Robert and Cunyet Capanoglu 2005. Triceratops: An effective platform for Developing Oil and Gas fields in deep and ultra deep water. Proc. of the fifteenth International Offshore and Polar Eng. Conference, Seoul, Korea, June 19-24, pp 133-139.

White. N. Charles, Copple. W. Robert and Cunyet Capanoglu 2005. Triceratops: An effective platform for Developing Oil and Gas fields in deep and ultra deep water. Proceedings of the fifteenth International Offshore and Polar Engineering Conference, Seoul, Korea, June 19-24, 133-139.

William C. de Boom, Pinkster Jo. A and Peter S. G. Tan 1984. Motion and tether force prediction of a TLP. J. of Waterway, Port, Coastal and Ocean Eng. 110(4): 472-486.

Witz. J. A, Patel. M. H and Harrison. J. H 1986. On the hydrodynamics of semisubmersibles with articulated members. Proc. of Royal Society of London, Series A, Mathematical and Physical Sciences. 403: 81-109.

Yan Fa-suo, Zhang Da-gang, Sun Li-Ping and Dai Yang-shan 2009. Stress verification of a TLP under extreme wave environment. J. of Marine science applications. 8: 132-136.

Yoneya. T and Yoshida. K 1982. The Dynamics of Tension Leg Platforms in Waves. J. of Energy Resources Technology. 104: 20-28.

Yoshida. K., Ozaki. M. and Oka. N 1984. Structural Response Analysis of Tension Leg Platforms. J. of Energy Resources. 106: 10-17.

Z.Demirbilek,1990. Design formulae for offset, set down and tether loads of a tension leg platform(TLP). Ocean Engineering, 17(5): 517-523.

Zeng Xiao-hui, Shen Xiao-peng and Wu Ying-xiang 2007. Governing equations and numerical solutions of tension leg platform with finite amplitude motion. J. of Applied Mathematics and Mechanics. 28(1): 37-49.

Important: Please enable javascript in your browser and download Adobe Flash player to view this site
Site Maintained by Web Studio, IIT Madras. Contact Webmaster: nptel@iitm.ac.in