Experimental Study on Wet Tow and Upending of a Truss Spar

2011 ◽  
Author(s):  
Lin Liu ◽  
Longfei Xiao ◽  
Zhiqiang Hu ◽  
Lijun Yang
Keyword(s):  
Experimental Study ◽  
Oil And Gas ◽  
Research Work ◽  
Hydrodynamic Characteristics ◽  
Test Results ◽  
Ocean Engineering ◽  
Spar Platform ◽  
Key Points ◽  
Truss Spar ◽  
Global Moment

In recent years, with the development of the deepwater oil and gas exploitation, the Spar platform has received more and more attention. A lot of research work has been done on the Spar platform, but experimental study on the process of wet tow and upending of Truss Spar is seldom conducted. Recently, a wet tow and upending model test of a Truss Spar was carried out in the State Key Laboratory of Ocean Engineering in Shanghai Jiao Tong University. The hydrodynamic characteristics and the global loads on the key points of the Truss Spar during the period of wet tow and upending are focused on. In the wet tow tests, the tow resistance, 6DOF motions, global loads and the relative wave elevations are measured and analyzed. During the upending simulation, the measuring parameters consist of the motions and the global moment at the connection points between the hard tank and the truss. The test program and test results are presented and discussed in this paper offering the value references for the wet tow and upending operation in reality of the Truss Spar.

Research on Collision Mechanism for a Ship Colliding With a Spar Platform

2007 ◽  
Author(s):  
Zhiqiang Hu ◽  
Weicheng Cui ◽  
Longfei Xiao ◽  
Jianmin Yang
Keyword(s):  
Numerical Simulation ◽  
Structural Damage ◽  
Simulation Method ◽  
Hydrodynamic Characteristics ◽  
Spar Platform ◽  
Mooring Lines ◽  
Hull Design ◽  
Truss Spar ◽  
Internal Mechanism ◽  
Double Hull

The collision mechanisms of spar platform haven’t caused so much attention as that of ships in the past, for the short of this kind of collision accidents reported. But this does not mean the impossibility of the collision accident in the future. The research on external mechanism and internal mechanism for a ship colliding with a spar platform is introduced in this paper. A model test is designed to study the external mechanism. The collision scenario is described as a ship colliding with a spar platform moored in 1500 meters water depth. The specifics of the spar’s motions and the tension forces of the mooring lines are gathered, to find the hydrodynamic characteristics in the collision scenario. It is found that the maximal displacements and the maximal pitch angles of the spar platform, and the maximal tension forces of mooring lines are all linearly proportional to the initial velocity of the striking ship basically. Mooring lines play elastic roles in the collision course. The internal mechanism of the ship colliding with the spar platform is achieved by numerical simulation method and the software used is MSC.DYTRAN. A Truss-Spar is taken as the object and a double hull structural design is adopted in the part of hard tank near water surface. The curves of collision characters and the structural damage are obtained. The crashworthiness of the double hull design is verified, through the numerical simulation results.

Strake Design and VIM-Suppression Study of a Cell-Truss Spar

2010 ◽  
Author(s):  
Ying Wang ◽  
Jianmin Yang ◽  
Tao Peng ◽  
Haining Lu
Keyword(s):  
Oil And Gas ◽  
Hydrodynamic Performance ◽  
Design Stage ◽  
Concept Design ◽  
Ocean Engineering ◽  
Design And Optimization ◽  
Fluid Field ◽  
Spar Platforms ◽  
Helical Strakes ◽  
Truss Spar

Along with the development of offshore technology, Spar platforms have been widely used in deep-sea oil and gas exploitation. Due to the deep draft cylinder hull piercing into the water, Spar platforms could be subjected to Vortex-Induced Motions (VIM) in certain current conditions. To mitigate VIM, helical strakes are used on the Spar hulls, and they have been proved to be effective. Cell-Truss Spar is a new concept of Spar platform which has recently been put forward by State Key Laboratory of Ocean Engineering (SKLOE) of Shanghai Jiao Tong University. It combines some good qualities of the Cell Spar and Truss Spar designs, aiming to bring in the lighter truss section and heave plate damping feature of the Truss Spar to obtain satisfactory heave motion performances, while reduce manufacture and installation difficulties by means of cell concept. Since the Cell-Truss Spar is a new design concept that has physical characteristics which are different from the existing Spars, the global motion performance should be carefully studied and verified. Researches about the VIM performance of the Cell-Truss Spar have been carried out recently (see Wang Ying et al, 2008, etc). Since it is still at the concept design stage, the Cell-Truss Spar configuration is considered without detail strake design in these studies. For the Cell-Truss Spar, which is still on concept design stage at the present time, the design and optimization of the helical strakes is very important to control the VIM response and improve the hydrodynamic performance. In this paper, strake design and VIM-Suppression Study of the Cell-Truss Spar is carried out. As a result of the unique characters on the hull, the outer surface of the Cell-Truss Spar does not form a regular cylinder. Hence, the strakes should be designed more carefully. In this study, four different configurations of strake groups are put forward and studied, and the one with the highest efficiency is chosen to be applied on the Cell-Truss Spar. The fluid field around the hard tank of the hull, the vortex disturbance near the strakes, and the forces acting on the hard tank with different strakes are simulated by CFD method, and the strake efficiency is assessed through model test combining with CFD computation. The optimized strake configuration is finally chosen, and the VIM performance of the strake-equipped Spar is studied.

Numerical Study on the Hydrodynamic Behavior of a New Cell-Truss Spar Platform

2007 ◽  
Author(s):  
Fan Zhang ◽  
Jian-Min Yang ◽  
Run-Pei Li ◽  
Gang Chen
Keyword(s):  
Oil And Gas ◽  
Numerical Study ◽  
Structure Design ◽  
Coupled Analysis ◽  
Hydrodynamic Behavior ◽  
Spar Platform ◽  
Truss Spar Platform ◽  
A Cell ◽  
Truss Spar ◽  
Heave Motion

The spar platform concept develops quickly in the oil and gas exploitations in offshore areas, especially in deep and ultra-deep water. From the first generation of classic spar, the spar concept has developed into the second generation of truss spar and the third generation of cell spar, and many new spar concepts are being put forward by the ocean structure design companies and research institutes. The purpose of those designs mainly focuses on the reduction of fabrication difficulties and cost, while satisfying the requirement of exploitation at meantime. This paper presents a numerical study on the hydrodynamic behavior of a cell-truss spar platform. Features of truss spar and cell spar were both taken into account in the new spar concept, aiming to take advantage of the heave plate damping feature of the truss spar to obtain satisfactory heave motion performance, while reduce manufacture and installation difficulties with cell concept. The whole spar concept with risers and mooring system were modeled by means of numerical simulation, and fully time-domain coupled analysis was conducted to investigate hydrodynamics of the spar platform both in operating and survival conditions.

Experimental study of influence of oil-cracking processes in hydrothermal solutions on formation of various types of oil-and-gas deposits

2011 ◽  
Vol 3 (Special Issue) ◽  
pp. 1-7
Author(s):  
V. S. Balitsky ◽  
M. A. Novikova ◽  
S. V. Penteley ◽  
L. V. Balitskaya ◽  
T. M. Bublikova
Keyword(s):  
Experimental Study ◽  
Oil And Gas ◽  
Hydrothermal Solutions ◽  
Oil Cracking

scholarly journals Experimental Study on Improvement of Marine Soft Soil with Alkali Residue

2018 ◽  
Vol 53 ◽  
pp. 04021
Author(s):  
SHAO Yong ◽  
LIU Xiao-li ◽  
ZHU Jin-jun
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Void Ratio ◽  
Soft Soil ◽  
Compressive Modulus ◽  
Engineering Properties ◽  
Test Results ◽  
Use Of Resources ◽  
One Year

Industrial alkali slag is the discharge waste in the process of alkali production. About one million tons of alkali slag is discharged in China in one year. It is a burden on the environment, whether it is directly stacked or discharged into the sea. If we can realize the use of resources, it is a multi-pronged move, so alkali slag is used to improve solidified marine soft soil in this paper. The test results show that the alkali residue can effectively improve the engineering properties of marine soft soil. Among them, the unconfined compressive strength and compressive modulus are increased by about 10 times, and the void ratio and plasticity index can all reach the level of general clay. It shows that alkali slag has the potential to improve marine soft soil and can be popularized in engineering.

Hydrodynamic characteristics of vertical and quadrant face pile supported breakwater under oblique waves

2021 ◽  
pp. 147509022110313
Author(s):  
T J Jemi Jeya ◽  
V Sriram ◽  
V Sundar
Keyword(s):  
Experimental Study ◽  
Hydrodynamic Performance ◽  
Hydrodynamic Characteristics ◽  
Scattering Parameter ◽  
Oblique Waves ◽  
Test Conditions ◽  
Relative Water ◽  
Identical Test ◽  
Run Up ◽  
Water Depths

This paper presents the results from a comprehensive experimental study on the Quadrant Face Pile Supported Breakwater (QPSB) in two different water depths exposed to three different oblique wave attacks. The results are compared with that for a Vertical face Pile Supported Breakwater (VPSB) for identical test conditions. The paper compares the reflection coefficient, transmission coefficient, energy loss coefficient, non-dimensional pressure, and non-dimensional run-up as a function of the relative water depth and scattering parameter. The results obtained for QPSB are validated with existing results. The salient observations show that QPSB experiences better hydrodynamic performance characteristics than the VPSB under oblique waves.

scholarly journals The Influence of the Asymmetric Arb Process on the Properties of Al-Mg-Al Multi-Layer Sheets / Wpływ Asymetrii W Procesie Arb Na Właściwości Wielowarstwowych Blach Al-Mg-Al

2015 ◽  
Vol 60 (4) ◽  
pp. 2821-2826 ◽  
Author(s):  
A. Wierzba ◽  
S. Mróz ◽  
P. Szota ◽  
A. Stefanik ◽  
R. Mola
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Tensile Strength ◽  
Rolling Process ◽  
Asymmetry Factor ◽  
Relative Reduction ◽  
Test Results ◽  
Initial Thickness ◽  
Asymmetric Rolling ◽  
Aluminium Layer

The paper presents the results of the experimental study of the three-layer Al-Mg-Al sheets rolling process by the ARB method. The tests carried out were limited to single-pass symmetric and asymmetric rolling processes. An Al-Mg-Al package with an initial thickness of 4 mm (1-2-1 mm) was subjected to the process of rolling with a relative reduction of 50%. To activate the shear band in the strip being deformed, an asymmetry factor of av=2 was applied. From the test results, an increase in the tensile strength of the multi-layer Al-Mg-Al sheets obtained from the asymmetric process was observed. Microhardness tests did not show any significant differences in aluminium layer between respective layers of sheets obtained from the symmetric and the asymmetric process. By contrast, for the magnesium layer, an increase in microhardness from 72 HV to 79 HV could be observed for the asymmetric rolling. The analysis of the produced Al-Mg-Al sheets shows that the good bond between individual layers and grain refinement in the magnesium layer contributed to the obtaining of higher mechanical properties in the multi-layer sheets produced in the asymmetric process compared to the sheets obtained from the symmetric process.

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