Experimental Evaluation of VIM on MPSO in Combined Environmental Conditions for Waves and Current

Author(s):  
Masakatsu Saito ◽  
Sotaro Masanobu ◽  
Tomoki Taniguchi ◽  
Kazuhisa Otsubo ◽  
Takayuki Asanuma ◽  
...  

MPSO, mono-column hull type FPSO, is attracting the interest as a floating production system which has high performance for motion and large tank capacity in recent years. The authors had performed a mooring system safety evaluation of a MPSO named ‘MONOBR’ which was assumed to be installed at the Gulf of Mexico in the international collaborative research and development project between PETROBRAS and JOGMEC. There exists a strong current called the Loop current in the Gulf of Mexico. It is known that cylindrical floaters like SPARs or MPSOs sway with the long period and large amplitude in the transverse direction of the current. The motion is called Vortex Induced Motion (VIM), and is caused by vortex shedding from the sidewall of the floater. VIM is one of the important issues in the safety evaluation of mooring system of MPSO. Generally, the combined environmental conditions in which wind, waves and current exist are concerned for the safety evaluation of mooring systems. Therefore, it needs to estimate VIM in waves and current. The authors had performed the VIM measurement tests in order to investigate the estimation method of VIM in waves and current. The results of the VIM measurement test in waves and current and the results of the mooring safety evaluation method using the estimation method of VIM in waves and current are described in this paper.

Author(s):  
Alberto Omar Vazquez-Hernandez

The conceptual design is an important stage of the engineering process of any floating production system. This design stage takes into account the specific site conditions and production requirements to find a feasible technical alternative of the system characteristics, from which in the next engineering stage the structure is improved. Among the basic characteristics of a floating production system are the hull main dimensions, which have to meet the production and stability requirements, as well as the mooring system characteristic. The mooring system definition mainly depends on the water depth, hull dimensions and the environmental site conditions. The environmental conditions are different from site to site, where in some sites around the world harsh conditions like hurricanes or typhoons may occur. Therefore, in the dimensioning of the mooring system such environmental conditions have to be considered. In the case of Gulf of Mexico, hurricane conditiones have presented a risk to the oil and gas existing facilities as it is evident on the severe damages and failures they have provoked in some cases. The present study aims to consider a computational tool that takes into account in the conceptual design stage a data base of hurricane conditions in Gulf of Mexico, as well as the production and site requirements so that to carry out the basic sizing of hull and mooring systems. The tool also considers a data base considering different hull sizes (wave force coefficients) and mooring materials to estimate the environmental loads and the mooring system design.


2013 ◽  
Vol 748 ◽  
pp. 1256-1261
Author(s):  
Shou Hui He ◽  
Han Hua Zhu ◽  
Shi Dong Fan ◽  
Quan Wen

At the present time, the Dow Chemical Fire and Explosion Index (F&EI) is a kind of risk index evaluation method that is comprehensively used in evaluating potential hazard, area of exposure, expected losses in case of fire and explosion, etc. As the research object to oil depot storage tank area, this article ultimately confirms establishing appropriate pattern of process unit as well as reasonable safety precautions compensating method, in order to insure the reasonableness of evaluating result, by means of selecting process unit, confirming material factor and compensating safety precautions, using F&EI method. This can provide the basis for theoretical ground in aspect of oil depot development and safety production management.


2021 ◽  
Vol 651 (4) ◽  
pp. 042058
Author(s):  
Xuan Sun ◽  
Zhiqiang Guo ◽  
Faguo Zhong ◽  
Zhibin Wu ◽  
Penghui Yang ◽  
...  

2019 ◽  
Vol 29 (1) ◽  
pp. 130-140 ◽  
Author(s):  
Florian Gerland ◽  
Alexander Wetzel ◽  
Thomas Schomberg ◽  
Olaf Wünsch ◽  
Bernhard Middendorf

Abstract Modern concretes such as ultra-high performance concrete (UHPC) show excellent strength properties combined with favorable flow properties. However, the flow properties depend strongly on process parameters during production (temperature, humidity etc.), but also change sensitively even with slight variations in the mixture. In order to ensure desired processing of the fluidlike material and consistent process quality, the flow properties of the concrete must be evaluated quantitatively and objectively. The usual evaluation of measurements from concrete rheometers, for example of the ball probe system type, does not allow the direct determination of the objective material parameters yield stress and plastic viscosity of the sample. We developed a simulation-based method for the evaluation of rheometric measurements of fine grained high performance concretes like self-compacting concrete (SCC) and UHPC. The method is based on a dimensional analysis for ball measuring systems. Through numerical parameter studies we were able to describe the identified relationship between measuring quantities and material parameters quantitatively for two devices of this type. The evaluation method is based on the Bingham model. With this method it is possible to measure both the yield stress and the plastic viscosity of the fresh sample simultaneously. Device independence of the evaluation process is proven and an application to fiber-reinforced UHPC is presented.


Author(s):  
Yonghong Yang ◽  
Yu Chen ◽  
Zude Tang

Increasing traffic volume and insufficient road lanes often require municipal roads to be reconstructed and expanded. Where a road passes under a bridge, the reconstruction and expansion project will inevitably have an impact on the bridge. To evaluate the safety impact of road engineering projects on bridges, this paper evaluates the safety of the roads and ancillary facilities of highway bridges involved in municipal road engineering projects. Based on a comprehensive analysis of the safety factors of municipal roads undercrossing existing bridges, a fuzzy comprehensive analytic hierarchy process (AHP) evaluation method for the influence of road construction on the safety of existing bridges is proposed. First, AHP is used to select 11 evaluation factors. Second, the target layer, criterion layer, and index layer of evaluation factors are established, then a safety evaluation factor system is formed. The three-scale AHP model is used to determine the weight of assessment indexes. Third, through the fuzzy comprehensive AHP evaluation model, the fuzzy hierarchical comprehensive evaluation is carried out for the safety assessment index system. Finally, the fuzzy comprehensive evaluation method is applied to the engineering example of a municipal road undercrossing an existing expressway bridge. The comprehensive safety evaluation of the existing bridge reflects the practicability and feasibility of the method. It is expected that, with further development, the method will improve the decision-making process in bridge safety assessment systems.


2010 ◽  
Vol 118-120 ◽  
pp. 601-605
Author(s):  
Han Ming

Evaluation method of reliability parameter estimation needs to be improved effectively with the advance of science and technology. This paper develops a new method of parameter estimation, which is named E-Bayesian estimation method. In the case one hyper-parameter, the definition of E-Bayesian estimation of the failure probability is provided, moreover, the formulas of E-Bayesian estimation and hierarchical Bayesian estimation, and the property of E-Bayesian estimation of the failure probability are also provided. Finally, calculation on practical problems shows that the provided method is feasible and easy to perform.


2010 ◽  
Vol 60 (5) ◽  
pp. 1075-1084 ◽  
Author(s):  
Yuehua Lin ◽  
Richard J. Greatbatch ◽  
Jinyu Sheng

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