Dynamic analysis of the gravity platform under random wave load

2011 ◽  
Author(s):  
Tianwei Pan ◽  
Yinbang Wang ◽  
Yiran Feng
Keyword(s):  
Dynamic Analysis ◽  
Random Wave ◽  
Wave Load ◽  
Gravity Platform

Dynamic Analysis of Gravity Platform's Marine Riser under Wave Load

2012 ◽  
Vol 166-169 ◽  
pp. 150-153
Author(s):  
Xin Wang ◽  
Yin Bang Wang ◽  
Nan Liu
Keyword(s):  
Dynamic Analysis ◽  
Bending Moment ◽  
Marine Riser ◽  
Wave Load ◽  
Ansys Simulation ◽  
Linear Differential ◽  
The Stability ◽  
Gravity Platform ◽  
Homogeneous Linear ◽  
Homogeneous Linear Differential Equation

Gravity platform was widely used in marginal oilfield, so the strength and the stability of its marine riser under wave load became very important. By simplifying the Morison equation, the paper made the dynamic analysis of the riser come down to solving the fourth order non-homogeneous linear differential equation, thus got the analytical solution of its deflection, shear force and bending moment. And the comparison with Ansys simulation showed that this simplified method was feasible.

scholarly journals An Analytical Procedure to Predict Transverse Vibration Response of Jack-Up Riser under the Random Wave Load

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Fengde Wang ◽  
Wensheng Xiao ◽  
Yanan Yao ◽  
Qi Liu ◽  
Changjiang Li
Keyword(s):  
Dynamic Response ◽  
Oil And Gas ◽  
Beam Theory ◽  
Random Wave ◽  
Wave Load ◽  
Main Component ◽  
Gas Leaks ◽  
Jack Up ◽  
Euler Bernoulli Beam ◽  
Transverse Response

Marine riser is a key equipment in offshore drilling operation, and failure of the riser can lead to drilling moratorium; in severe cases, it may cause oil and gas leaks. In this paper, the time-dependent boundary conditions of the riser and the randomness of wave load are considered to improve the calculation efficiency and accuracy of the dynamic response of the jack-up riser. Based on the Euler–Bernoulli beam theory, an analytical method to determine the response of the jack-up riser subjected to the random wave load was established by the Mindlin–Goodman method in the frequency domain, and an experiment was carried out to verify it. The research shows that transverse dynamic response is the main component of the transverse response of the riser, and the method proposed is feasible to calculate the transverse response of the riser.

Dynamic Response Analysis of Small Oil Tanker Based on AQWA

2013 ◽  
Vol 779-780 ◽  
pp. 757-762
Author(s):  
Jin Hao Xu ◽  
Yue Qin Liu ◽  
Chao He Chen
Keyword(s):  
Ship Motion ◽  
Response Analysis ◽  
Random Wave ◽  
Wave Load ◽  
Irregular Wave ◽  
Response Amplitude Operators ◽  
Two Parameters ◽  
Oil Tanker ◽  
Calculation Software

Ship navigation performance more and more attention in real sea conditions.To study the properties of ship motion in waves, Applling hydrodynamics calculation software for AQWA-line and AQWA-AGS modules and taking into account the role of random wave load, 2450DWT a small oil tanker in simulation and analysis of a campaign response under sea conditions, Calculate shipping in several waves under the angle of vertical and horizontal swing, heave, pitch, roll and the first rolling response amplitude operators of RAOs, additional parameters such as quality and radiation damping. Application of spectrum analysis method, ITTC wave with two parameters, which strike the spectral density of ship motion, and finally using Excel to calculate sprawling forecast prediction of ship under irregular wave.

Fatigue Analysis of Penetration Assembly Joined by Multi-Pass Welding

2010 ◽  
Vol 452-453 ◽  
pp. 317-320
Author(s):  
Hong Li ◽  
Li Li ◽  
Ren Fu Wang
Keyword(s):  
Residual Stresses ◽  
Transient Temperature ◽  
Random Wave ◽  
Remaining Life ◽  
Wave Load ◽  
Dynamic Stresses ◽  
Welded Structures ◽  
Time Dynamic ◽  
Transient Temperature Field ◽  
Damage Law

Due to high centralized instantaneous heat input in the process of the welding, a great deal of residual stresses and distortions should be brought in the welded structures, which can heavily influence the capability and reliability of the structure. Residual stresses and welding fatigue behaviors of stainless steel penetration assembly joined by multi-pass welding are studied in this paper. The distribution of transient temperature field and real-time dynamic stresses field in the welded region must be calculated first. Based on the residual stresses, the random wave load putting on the structure and fatigue factors, according to Miner fatigue damage law, some fatigue behaviors such as fatigue life and remaining life are obtained.

Dynamic Analysis of Offshore Monopile Wind Turbine Including the Effects of Wind-Wave Loading and Soil Properties

2013 ◽  
Author(s):  
Muk Chen Ong ◽  
Hui Li ◽  
Bernt J. Leira ◽  
Dag Myrhaug
Keyword(s):  
Dynamic Analysis ◽  
Wind Turbine ◽  
Load Transfer ◽  
Wind Wave ◽  
Dynamic Responses ◽  
Soil Conditions ◽  
Sand Layer ◽  
Clay Layer ◽  
Wave Load ◽  
Z Curve

An engineering approach to dynamic analysis of an offshore monopile wind turbine is presented in this paper. The wind-wave coupling for shallow water conditions is considered. Different wind, wave and current loads on the wind turbine within the cut-in and cut-off conditions are taken into account. The hydrodynamic loading is computed based on the corresponding sea-states. The interaction between the foundation and the soil is simulated by nonlinear springs, which stiffness properties are obtained from the axial load transfer (t-z) curve, the tip load-displacement (Q-z) curve and the lateral load-deflection (p-y) curve. Three types of soil conditions are considered in the simulations, i.e., 100% sand layer, 50% sand layer (top) and 50% clay layer (bottom), as well as 100% clay layer. For a given current speed, the variations of the static and the dynamic responses of the wind turbine due to the effects of different wind-wave load combinations and soil conditions have been investigated and discussed.

scholarly journals Prediction of Deepwater FPSO responses using different numerical analysis methods

2018 ◽  
Vol 34 ◽  
pp. 02032 ◽  
Author(s):  
Matthew Guan ◽  
Montasir Osman ◽  
Cheng Yee Ng
Keyword(s):  
Dynamic Analysis ◽  
Numerical Models ◽  
Mooring Line ◽  
Random Wave ◽  
Static System ◽  
Line System ◽  
Wave Condition ◽  
Coupled Dynamic Analysis ◽  
Linear Spring ◽  
Spring System

The limitations of existing wave basins present a significant challenge when modelling offshore deepwater systems, particularly due to the basin’s relatively shallow depth. Numerical simulation thus becomes valuable in predicting its behaviour during operation at sea. The coupled dynamic analysis is preferred over the traditional quasi-static method, as the former enables the inclusion of damping and added mass properties of the complete mooring line system, which becomes increasingly prominent at greater water depths. This paper investigates the motions and mooring line tensions of a turret moored Floating Production Storage Offloading (FPSO) platform using three numerical models, i.e. a dynamic system, quasi-static system and linear spring system subjected to unidirectional random wave condition. Analysis is carried out using a commercial software AQWA. The first two numerical models utilise a complete system of the same setup and configuration, while the linear spring system substitutes the mooring lines with equivalent linear springs and attempts to match the total mooring line restoring forces with that of the coupled dynamic analysis. The study demonstrates the significance of coupled dynamic analysis on the responses of an FPSO in deepwater. The numerical model of the FPSO is validated against the results of a published work.

Effect of current on the dynamic response of a bi-articulated offshore tower

2020 ◽  
Vol 23 (14) ◽  
pp. 3089-3101
Author(s):  
Mohd Moonis Zaheer ◽  
Nazrul Islam
Keyword(s):  
Dynamic Response ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Equations Of Motion ◽  
Bending Moment ◽  
Dynamic Effect ◽  
Random Wave ◽  
Wave Load ◽  
Environmental Loads ◽  
Power Spectral

Wind and wave loadings have a predominant role in the design of articulated offshore towers for its successful service and survival. Such towers are very sensitive to the dynamic effect of environmental loads. The compliant nature of these towers with environmental loads introduces geometric nonlinearity due to large displacements, which becomes an important consideration in the analysis of these towers. This article deals with the dynamic response of a bi-articulated offshore tower to wind, wave, and current forces. The exposed portion of the tower is subjected to the action of wind, while the submerged portion is acted upon by random wave and current forces. Wind load is modeled by Ochi and Shin spectrum, while the wave load is characterized by Pierson–Moskowitz spectrum. The nonlinear dynamic equations of motion are derived by Hamilton’s principle. Response of the tower is determined by a time domain iterative (Wilson-θ) method. Power spectral density of important parameters such as surge, tilting motion, hinge shear, and bending moment are presented under high and low sea states. It is observed that response of tower due to current modifies the peak energy of power spectral density functions.

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