Drilling Riser Model Test for Software Verification

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Decao Yin ◽  
Halvor Lie ◽  
Massimiliano Russo ◽  
Guttorm Grytøyr
Keyword(s):  
Model Test ◽  
Software Verification ◽  
Dynamic Responses ◽  
Wave Loads ◽  
Marine Riser ◽  
Test Program ◽  
Video Recordings ◽  
Severe Fatigue ◽  
Drilling Unit ◽  
Boundary Model

Marine drilling riser is subject to complicated environmental loads which include top motions due to mobile offshore drilling unit (MODU), wave loads, and current loads. Cyclic dynamic loads will cause severe fatigue accumulation along the drilling riser system, especially at the subsea wellhead (WH). Statoil and BP have carried out a comprehensive model test program on drilling riser in MARINTEK's Towing Tank in February 2015. The objective is to validate and verify software predictions of drilling riser behavior under various environmental conditions by the use of model test data. Six drilling riser configurations were tested, including different components such as upper flex joint (UFJ), tensioner, marine riser, lower marine riser package (LMRP), blow-out preventer (BOP), lower flex joint (LFJ), buoyancy elements, and seabed boundary model. The drilling riser models were tested in different load conditions. Measurements were made of microbending strains and accelerations along the riser in both in-line (IL) and crossflow (CF) directions. Video recordings were made both above and under water. In this paper, the test setup and test program are presented. Comparisons of results between model test and RIFLEX simulation are presented on selected cases. Preliminary results show that the drilling riser model tests are able to capture the typical dynamic responses observed from field measurement, and the comparison between model test and RIFLEX simulation is promising.

Drilling Riser Model Tests for Software Verification

2016 ◽  
Author(s):  
Decao Yin ◽  
Halvor Lie ◽  
Massimiliano Russo ◽  
Guttorm Grytøyr
Keyword(s):  
Model Test ◽  
Software Verification ◽  
Cross Flow ◽  
Model Tests ◽  
Dynamic Responses ◽  
Wave Loads ◽  
Regular Wave ◽  
Marine Riser ◽  
Test Program ◽  
Irregular Wave

Marine drilling riser is subject to complicated environmental loads which include top motions due to Mobile Offshore Drilling Unit (MODU), wave loads and current loads. Cyclic dynamic loads will cause severe fatigue accumulation along the drilling riser system, especially at the subsea well head (WH). Statoil and BP have carried out a comprehensive model test program on drilling riser in MARINTEK’s Towing Tank in February 2015. The objective is to validate and verify software predictions of drilling riser behaviour under various environmental conditions by use of model test data. Six drilling riser configurations were tested, including different components such as Upper Flex Joint (UFJ), tensioner, marine riser, Lower Marine Riser Package (LMRP), Blow-Out Preventer (BOP), Lower Flex Joint (LFJ), buoyancy elements and seabed boundary model. The drilling riser models were tested in different load conditions: 1. Forced top motion tests 2. Regular wave test 3. Combined regular wave and towing test 4. Irregular wave test 5. Combined irregular wave and towing test 6. Towing test (VIV) Measurements were made of micro bending strains and accelerations along the riser in both In-Line (IL) and Cross-Flow (CF) directions. Video recordings were made both above and under water. In this paper, the test set-up and test program are presented. Comparisons of results between model test and RIFLEX simulation are presented on selected cases. Preliminary results show that the drilling riser model tests are able to capture the typical dynamic responses observed from field measurement, and the comparison between model test and RIFLEX simulation is promising.

Model Tests of a Spar-Type Floating Wind Turbine Under Wind/Wave Loads

2015 ◽  
Author(s):  
Fei Duan ◽  
Zhiqiang Hu ◽  
Jin Wang
Keyword(s):  
Wind Turbine ◽  
Model Test ◽  
Wind Wave ◽  
Wave Model ◽  
Offshore Structures ◽  
Model Tests ◽  
Wave Loads ◽  
Scaled Model ◽  
Floating Wind Turbine ◽  
Wave Effects

Wind power has great potential because of its clean and renewable production compared to the traditional power. Most of the present researches for floating wind turbine rely on the hydro-aero-elastic-servo simulation codes and have not been exhaustively validated yet. Thus, model tests are needed and make sense for its high credibility to master the kinetic characters of floating offshore structures. The characters of kinetic responses of the spar-type wind turbine are investigated through model test research technique. This paper describes the methodology for wind/wave model test that carried out at Deepwater Offshore Basin in Shanghai Jiao Tong University at a scale of 1:50. A Spar-type floater was selected to support the wind turbine in this test and the model blade was geometrically scaled down from the original NREL 5 MW reference wind turbine blade. The detail of the scaled model of wind turbine and the floating supporter, the test set-up configuration, the mooring system, the high-quality wind generator that can create required homogeneous and low turbulence wind, and the instrumentations to capture loads, accelerations and 6 DOF motions are described in detail, respectively. The isolated wind/wave effects and the integrated wind-wave effects on the floating wind turbine are analyzed, according to the test results.

Theoretical Study on Hydroelastic Responses of Very Large Floating Structures Near Islands and Reefs

2014 ◽  
Author(s):  
Chao Tian ◽  
Xinyun Ni ◽  
Jun Ding ◽  
Peng Yang ◽  
Yousheng Wu
Keyword(s):  
Large Scale ◽  
Oil And Gas ◽  
Linear Equations ◽  
Dynamic Responses ◽  
Wave Loads ◽  
Structural Dynamic ◽  
Floating Structures ◽  
Geological Conditions ◽  
Incident Waves ◽  
Very Large Floating Structures

In order to explore the fishery, oil and gas, and tourism resources in the ocean, Very Large Floating Structures (VLFS) can be deployed near islands and reefs as a logistic base with various functions such as a floating harbor, accommodation, fishery processing, oil and gas exploration, environment surveillance, airplane landing and taking off, etc. However, in addition to the complicated hydroelastic coupling effects between the hydrodynamic loads and structural dynamic responses, when tackling the hydroelastic problems of floating structures deployed near islands and reefs, several other environmental effects and numerical techniques should be taken into account: 1) The influences of the non-uniform incident waves (multi-directions, different wave frequencies); 2) Complex seabed profile and its impact on the incident waves; 3) Nonlinear second order wave exciting forces in the complex mooring system, shallow water and coral reef geological conditions; 4) Parallel computing technology and fast solving methods for the large scale linear equations, accounting for the influence of dramatic increase of number of meshes to the computation efforts and efficiency. In the present paper the theoretical investigation on the hydroelastic responses of VLFS deployed near islands and reefs has been presented. In addition, based on the pulsating source Green function, the high performance parallel fast computing techniques and other numerical methods, in solving large scale linear equations, have been introduced in the three-dimensional hydroelastic analysis package THAFTS. The motions, wave loads, distortions and stresses can be calculated using the present theoretical model and the results can be used in the design and safety assessment of VLFS.

Improved Strake Design for Vortex Induced Motions of Spar Platforms

2005 ◽  
Author(s):  
Mehernosh Irani ◽  
Lyle Finn
Keyword(s):  
Model Test ◽  
Model Tests ◽  
Test Results ◽  
Test Program ◽  
Test Set ◽  
Test Methodology ◽  
Spar Platforms ◽  
Truss Spar ◽  
Set Up

An extensive model test program was conducted to explore the effectiveness of alternate strake designs to reduce Truss Spar VIV response. Different strake configurations were tested to minimize VIV response. The paper presents results of the model tests. The model test set-up is described, important parameters that are modeled (including hull and truss geometry, strake configuration, mass and mooring properties) and considerations of instrumentation and test methodology are discussed. The paper also describes the analysis of the test results and shows the effectiveness of new strake design. The present results are compared with VIV response of existing Truss Spars with conventional strake design.

A Simplified Method for Response Behavior and Reliability Analysis of Long Submerged Structures With Tension Legs in Irregular Waves

2002 ◽  
Author(s):  
Shinji Katsura ◽  
Hiroo Okada ◽  
Koji Masaoka ◽  
Takashi Tsubogo ◽  
Kiko Shimada
Keyword(s):  
Limit State ◽  
Experimental Studies ◽  
Estimation Method ◽  
Dynamic Responses ◽  
Irregular Waves ◽  
Elastic Response ◽  
Tunnel Structure ◽  
Wave Loads ◽  
Response Behavior ◽  
Wave Conditions

This paper deals with the elastic response behavior of marine tunnel structures with tension legs in regular and irregular waves. Firstly, a simplified estimation method for dynamic responses under regular wave conditions is analytically presemed using a simple beam on an elastic foundation. Then, in order to demonstrate the validity of above results, experimental studies are carried out for a marine tunnel structure model with tension legs under wave-induced loads. Next, a simplified estimation method is presented for the elastic response behavior under irregular wave conditions by using above analytical results and combining irregular sea wave spectra. Then, the limit state failure mode of the main structure is presented for estimating the reliability level for cracking failure under extreme wave loads. Finally, the applicability of the methods is investigated through numerical examples carried out for a 1,000m-class marine tunnel structure with tension legs under some irregular sea state conditions. And characteristics of the short-term responses and reliability levels for the cracking failure are numerically shown.

Overview of the Ares I scale model test program

2011 ◽  
Vol 130 (4) ◽  
pp. 2542-2542
Author(s):  
Douglas D. Counter ◽  
Janice Houstion
Keyword(s):  
Model Test ◽  
Scale Model ◽  
Test Program ◽  
Ares I

scholarly journals Explicit Time-Domain Approach for Random Vibration Analysis of Jacket Platforms Subjected to Wave Loads

2020 ◽  
Vol 8 (12) ◽  
pp. 1001
Author(s):  
Wei Lin ◽  
Cheng Su ◽  
Youhong Tang
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Time Domain ◽  
Vibration Analysis ◽  
Random Vibration ◽  
Present Approach ◽  
Dynamic Responses ◽  
Wave Loads ◽  
Morison Equation ◽  
Random Vibration Analysis

This paper is devoted to the random vibration analysis of jacket platforms under wave loads using the explicit time-domain approach. The Morison equation is first used to obtain the nonlinear random wave loads, which are discretized into random loading vectors at a series of time instants. The Newmark-β integration scheme is then employed to construct the explicit expressions for dynamic responses of jacket platforms in terms of the random vectors at different time instants. On this basis, Monte Carlo simulation can further be conducted at high efficiency, which not only provides the statistical moments of the random responses, but also gives the mean peak values of responses. Compared with the traditional power spectrum method, nonlinear wave loads can be readily taken into consideration in the present approach rather than using the equivalent linearized Morison equation. Compared with the traditional Monte Carlo simulation, the response statistics can be obtained through the direct use of the explicit expressions of dynamic responses rather than repeatedly solving the equation of motion. An engineering example is analyzed to illustrate the accuracy and efficiency of the present approach.

Nonlinear Analysis of Vortex Induced Dynamic Response of Marine Riser

2013 ◽  
Vol 353-356 ◽  
pp. 2736-2740
Author(s):  
Lin Lin ◽  
Yan Ying Wang
Keyword(s):  
Dynamic Response ◽  
Cross Flow ◽  
Dynamic Responses ◽  
Marine Riser ◽  
Governing Equations ◽  
Nonlinear Dynamic Response ◽  
Wake Oscillator Model ◽  
Wake Oscillator ◽  
Flow Profiles ◽  
Line Force

Vortex-induced dynamic response is the most important issue influencing marine riser. This paper presents an investigation on the vortex-induced nonlinear dynamic response of marine riser subjected to combined waves,currents and platform movement. The in-line force was solved by Morison equation under combined waves,currents and platform movement while cross-flow force was solved by wake oscillator model. Updated Lagrangianmethod was used to solve the nonlinear problem.The governing equations were discretized by finite element method and solved by Newmark-β method in time domain. Influence of nonlinearity, comparisons of vortex-induced dynamic responses under different boundary conditions and different flow profiles were discussed.

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