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The Loads and Responses Committee Final Report and Recommendations to the 22nd ITTC
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GENERAL Membership and Meetings
The Committee appointed by the 21st ITTC consisted of the following members: • Ms. Kathryn K. McCreight (chairman), David Taylor Model Basin, MD, USA • Dr. Johan E. W. Wichers (secretary), Maritime Research Institute Netherlands (MARIN), The Netherlands (present MARIN USA Inc.) • Professor Grant E. Hearn, University of Newcastle upon Tyne, UK • Dr. Ole A. Hermundstad, Norwegian Marine Technology Research Institute (MARINTEK), Norway • Professor Tsugukiyo Hirayama, Yokohama National University, Yokohama, Japan • Professor Wataru Koterayama, Kyushu University, Kasuga, Japan • Dr. Allan R. Magee, BEC, Val de Reuil, France • Mr. Adolfo Marón, Canal de Experiencias Hidrodinámicas, Madrid, Spain • Dr. Deuk-Joon Yum, Hyundai Maritime Research Institute, Ulsan, Korea Dr. Magee moved from BEC and resigned from the committee in July 1998. Four committee meetings were held: • David Taylor Model Basin, MD, USA-May,
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1997 University of Newcastle upon Tyne, UK, December, 1997 Congress Building, The Hague, the Netherlands (PRADS'98), September, 1998 Hyundai Maritime Research Institute, Ulsan, Korea, February, 1999
Recommendations of the 21st ITTC
The 21st ITTC recommended that the Loads and Responses Committee carry out the following work: • Review the state-of-the-art, comment on the potential impact of new developments on the ITTC, and identify the need for research and development in the areas of seakeeping and ocean engineering. Monitor and follow the developments of new experimental techniques and extrapolation methods. • Review the ITTC recommended procedures, benchmark data, and test cases for validation and uncertainty analysis and update as required. • Identify the requirements for new procedures, benchmark data, validation, uncertainty analyses and stimulate the necessary research for their preparation. • Prepare an up-to-date bibliography of relevant technical papers and reports. • Review progress made in studying the mechanism of deck wetness impact loads,
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bottom and bow flare slamming loads and the impact of green water and wave loads on moored offshore vessels. Examine hydroelastic problems in ocean engineering. Identify sources and interaction of potential and viscous origin forces to determine the low frequency motions of moored offshore vessels. Develop a standard formulation of wave spectrum for short-crested seas including sea waves and swell.
The literature survey also includes the related topics of developments in the numerical prediction of forces on ships, added resistance, and wind loads. The following chapters detail the tasks undertaken by the Committee: Chapter 2 - Developments in experimental techniques Chapter 3 - ITTC recommended procedures Chapter 4 - Benchmark experimental data Chapter 5 - Multi-directional wave spectra Chapter 6 - Water impact Chapter 7 - Hydroelastic problems in ocean engineering Chapter 8 - Forces which determine the low frequency motions of moored vessels Chapter 9 - Added resistance Chapter 10 - Trends in the Numerical Prediction of Ship Motions Chapter 11 - Wind loads Chapter 12 - Conclusions and Recommendations Chapter 13 - References 2.
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DEVELOPMENTS IN EXPERI-MENTAL TECHNIQUES Questionnaire on experimental instrumentation
The loads and responses committee is concerned with the theoretical and experimental
prediction of forces and motions of ships and ocean engineering structures due to wind, waves and current. Often, experimental results are correlated with the results of computations. The accuracy of the measured results affects interpretation of the correlation. State-of the-art measurement equipment is a desire of all basins. A review of the typical and newly developed instrumentation as used by the ITTC members may be necessary. For this purpose a questionnaire was established and sent to all model basin members. The questionnaire consisted of two parts. Part I asked information on typical instrumentation, while Part II concerned information on newly developed instrumentation. Part I: typical instrumentation. Typical instrumentation means the type of equipment which is routinely used in a facility. The purpose is to inform the members of the ITTC of the measuring techniques which are typically used in the affiliate test facilities. The information requested applies to the principles of the measuring techniques and signal transmissions of the following type of measurements: Calibration of environment: • wave heights and current and wind velocities. Motion responses: • linear motions and angular motions (surfaced and submerged models, including degrees of freedom), • relative wave height, freeboard and water on deck, • accelerations. Load responses: • force/bending moment transducers: - large range-number of components (forces : # - "
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