Nonlinear response of fixed jacket offshore platform under structural and wave loads

2013 ◽  
Vol 2 (1) ◽  
pp. 111-126 ◽  
Author(s):  
Shehata E. Abdel Raheem
Keyword(s):  
Nonlinear Response ◽  
Offshore Platform ◽  
Wave Loads ◽  
Jacket Offshore Platform

Study on Seismic Performance of Offshore Platform with Rocking Wall - TMD System

2014 ◽  
Vol 610 ◽  
pp. 78-83
Author(s):  
Ji Gang Zhang ◽  
Zhi Wei Jiang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Seismic Performance ◽  
Tuned Mass Damper ◽  
Offshore Platform ◽  
Element Analysis ◽  
Mass Damper ◽  
Jacket Offshore Platform ◽  
Rocking Wall ◽  
Wall System

Offshore platform rocking wall system and tuned mass damper are briefly introduced, and the paper integrates the advantages of these two kinds of seismic method, and the TMD is attached to the jacket offshore platform - rocking wall system, using the ANSYS for finite element analysis, and the analysis results are optimized. The results show that compared with the offshore platform - rocking wall system, additional TMD can give full play to the performances of the two kinds of seismic methods, which is remarkable.

Study on Reliability of Jacket Offshore Platform by Seismic Action Based on ANSYS

2010 ◽  
Vol 163-167 ◽  
pp. 3023-3028
Author(s):  
Qing Zhi Yan ◽  
Zhan Zhang ◽  
Liang Cui ◽  
Yan Hua Wang
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Failure Mode ◽  
Safety Assessment ◽  
Offshore Platform ◽  
Seismic Action ◽  
Structure Reliability ◽  
The Monte Carlo Method ◽  
Jacket Offshore Platform ◽  
Main Factor

Jacket Offshore Platform is a complex statically indeterminate structure, reliability of which is impacted by many factors, and the earthquake is a main factor. This paper simplify the significant failure mode of Jacket Offshore Platform by standard. Calculate the reliability of Jacket Offshore Platform under the effect of earthquake with the Monte Carlo method based on ANSYS. The result can provide evidence for safety assessment of Jacket Offshore Platform.

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.

scholarly journals Structural Damage Identification of Pipe Based on GA and SCE-UA Algorithm

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Yaojin Bao ◽  
He Xia ◽  
Zhenming Bao ◽  
Shuiping Ke ◽  
Yahui Li
Keyword(s):  
Genetic Algorithm ◽  
Structural Damage ◽  
Damage Identification ◽  
Offshore Platform ◽  
Identification Accuracy ◽  
Mode Shapes ◽  
Intelligent Algorithm ◽  
Damage Diagnosis ◽  
Jacket Offshore Platform ◽  
Ship Collision

Structure of offshore platform is very huge, which is easy to be with crack caused by a variety of environmental factors including winds, waves, and ice and threatened by some unexpected factors such as earthquake, typhoon, tsunami, and ship collision. Thus, as a main part of the jacket offshore platform, pipe is often with crack. However, it is difficult to detect the crack due to its unknown location. Genetic algorithm (GA) and SCE-UA algorithm are used to detect crack in this paper, respectively. In the experiment, five damages of the pipe in the platform model can be intelligently identified by genetic algorithm (GA) and SCE-UA. The network inputs are the differences between the strain mode shapes. The results of the two algorithms for structural damage diagnosis show that both of the two algorithms have high identification accuracy and good adaptability. Furthermore, the error of SCE-UA algorithm is smaller. The results also suggest that the structural damage of pipe can be identified by intelligent algorithm.

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