EXPERIMENTAL INVESTIGATION OF WAVE LOADS ON OFFSHORE PLATFORM WITH INVERTED CONE COLUMN

2011 ◽  
pp. 1625-1633
Author(s):  
JING ZHAO ◽  
YANLONG QIN ◽  
SHIPENG WANG
Keyword(s):  
Experimental Investigation ◽  
Offshore Platform ◽  
Wave Loads ◽  
Inverted Cone

Vibration Control of Offshore Platform Structure with Friction Dampers

2014 ◽  
Vol 638-640 ◽  
pp. 318-321
Author(s):  
Da Hai Zhao ◽  
Jing Lin Zhang
Keyword(s):  
Energy Dissipation ◽  
Vibration Control ◽  
Equation Of Motion ◽  
Offshore Platform ◽  
Wave Loads ◽  
Friction Damper ◽  
Friction Dampers ◽  
Offshore Platform Structure ◽  
Better Than

The performance of friction dampers to mitigate waves and earthquakes in tower-type offshore platform is investigated in this paper. Taking the offshore platform of TOWER-1 as an example, the equation of motion of offshore platform structure under earthquake and wave loads was established. The response reductions of offshore platform structure by different peak earthquakes were analyzed. The results show that the responses of the tower-type offshore platform structure under wave and earthquake could be effectively reduced by friction damper, and the energy dissipation ability of the friction damper differs in the different floors. The friction dampers give good response reductions in different peak earthquakes, and the response reductions of displacement are better than those of acceleration.

Efficient sampling for extreme event statistics of the wave loads on an offshore platform

2017 ◽  
Author(s):  
Mustafa A. Mohamad ◽  
Themistoklis P. Sapsis
Keyword(s):  
Extreme Event ◽  
Nonlinear Dynamical Systems ◽  
Computational Cost ◽  
Gaussian Process Regression ◽  
Optimization Procedure ◽  
Offshore Platform ◽  
Irregular Waves ◽  
Dimensional System ◽  
Wave Loads ◽  
Quantity Of Interest

We develop a method for the evaluation of extreme event statistics associated with nonlinear dynamical systems, using a very small number of samples. From an initial dataset of design points, we formulate a sequential strategy that provides the ‘next-best’ data point (set of parameters) that when evaluated results in improved estimates of the probability density function (pdf) for a scalar quantity of interest. The approach utilizes Gaussian process regression to perform Bayesian inference on the parameter-to-observation map describing the quantity of interest. We then approximate the desired pdf along with uncertainty bounds utilizing the posterior distribution of the inferred map. The ‘next-best’ design point is sequentially determined through an optimization procedure that selects the point in parameter space that maximally reduces uncertainty between the estimated bounds of the pdf prediction. Since the optimization process utilizes only information from the inferred map it has minimal computational cost. Moreover, the special form of the criterion emphasizes the tails of the pdf. The method is applied to estimate the extreme event statistics for a very high-dimensional system with millions degrees of freedom: an offshore platform subjected to three-dimensional irregular waves. It is demonstrated that the developed approach can accurately determine the extreme event statistics using orders of magnitude smaller number of samples compared with traditional approaches.

Experimental investigation on a freestanding bridge tower under wind and wave loads

2016 ◽  
Vol 57 (5) ◽  
pp. 951-968 ◽  
Author(s):  
Xiaodong Bai ◽  
Anxin Guo ◽  
Hao Liu ◽  
Wenli Chen ◽  
Gao Liu ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Wave Loads ◽  
Bridge Tower

Experimental Investigation of Wave Loads on Ice Masses at Different Proximity to Fixed Offshore Structure

2016 ◽  
Author(s):  
Tanvir Sayeed ◽  
Bruce Colbourne ◽  
David Molyneux ◽  
Ayhan Akinturk
Keyword(s):  
Experimental Investigation ◽  
Wave Loads ◽  
Offshore Structure

Interaction of Nomadic Bergy Bits With an Offshore Gravity Based Structure in Waves

2018 ◽  
Author(s):  
Dong Cheol Seo ◽  
M. Hasanat Zaman ◽  
Ayhan Akinturk
Keyword(s):  
Newfoundland And Labrador ◽  
Oil And Gas ◽  
Risk Mitigation ◽  
Offshore Platform ◽  
Wave Loads ◽  
Combined Load ◽  
Oil And Gas Operations ◽  
Reliable Design ◽  
Offshore Oil And Gas ◽  
Fixed Offshore Platform

Offshore oil and gas operations are being conducted in harsh environments such as offshore fields around Newfoundland and Labrador. The platforms used in these fields may be exposed to additional risks due the presence of drifting ice pieces in various sizes. To avoid a dangerous collision with a large floating ice, ice management and risk mitigation plans are required firstly. In case of smaller ice pieces (or bergy bits), if they collide with an offshore platform, the combined load of bergy bits and waves may be larger than the typical design wave loads. Hence, it is necessary to predict how these bergy bits may interact with a platform in a given sea state to estimate the combined load for developing a reliable design. In this paper, dynamic interaction between a moving bergy bit and a fixed offshore platform is simulated using CFD (Computation Fluid Dynamics) method. Trajectories and velocities of ice are simulated and compared to understand the hydrodynamic interaction by applying a series of different wave conditions such as wave period, height and relative incident peak location. The simulation outcomes show the importance and possibilities to apply it to the design process of such structures in the ocean.

The Development of 3D Hydroelastic Software and its Application on Platform

2019 ◽  
Author(s):  
Xinyun Ni ◽  
Zhengwei Zhang ◽  
Chao Tian ◽  
Ye Lu ◽  
Jun Ding
Keyword(s):  
Frequency Domain ◽  
Performance Prediction ◽  
Offshore Structures ◽  
Offshore Platform ◽  
Wave Loads ◽  
Interaction Method ◽  
Subsequent Work ◽  
The Past ◽  
Fast Processing ◽  
Important Branch

Abstract In the past few decades, 3D hydroelastic theory, an important branch of ship mechanics, has been developing dramatically. It offers a fluid-structure interaction method calculating response of structure of ship or offshore platform directly, which plays an significant role in the evaluation of wave loads on maritime structures. For platform with multiple modules, it is not only referred to loads on modules themselves but also to connectors’ loads between modules for their performance prediction. Absolutely, the 3D hydroelastic method described here can solve this problem accurately and directly. In this paper, 3D hydroelastic software, named COMPASS-THAFTS, has been developed by CSSRC and CCS on the basis of 3D hydroelastic theory initially established by Wu (1984). This software is very proper for designers and researchers of offshore structures because of its convenient and fast processing function. The COMPASS-THAFTS software mainly contains two modules, frequency-domain module and time-domain module. In this paper, we will focus our attention on introduction of integrated framework and processing functions in frequency domain module of COMPASS-THAFTS. Taking a certain offshore platform as application object, the 3D hydroelastic responses are calculated and the results are processed, and finally, the internal rules of data are analyzed. In subsequent work, some new modules, such as mooring module, will be integrated into COMPASS-THAFTS.

Hydroelasticity and Wave Loads for a Full-Form Ship with Shallow Draft

1992 ◽  
Vol 36 (03) ◽  
pp. 280-285
Author(s):  
Yan Qiu Dong ◽  
Weixue Lin
Keyword(s):  
Experimental Investigation ◽  
Computer Program ◽  
Theoretical Calculations ◽  
Dynamic Responses ◽  
Wave Loads ◽  
Hull Form ◽  
Hull Structure ◽  
Strip Theory ◽  
Full Form ◽  
Special Computer Program

A shallow-draft full-form ship is a particular type of ship with a breadth-to-draft ratio higher than is conventional. To investigate the characteristics of such full forms in response to hull vibrations induced by waves, a special computer program based on the hydroelasticity theory of ships has been developed. In addition, an experimental investigation using a segmented elastic-keel model of the ship has been carried out in order to verify the theoretical calculations. It is found from calculation of the wave loads that the dynamic responses of this specific hull form cannot be accurately predicted by strip theory. It is concluded therefore that hydroelasticity theory should be used in the design of the hull structure.

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