Discussion on the design value of environmental condition in offshore structure design

Ding, Jieying; Jia-hua, Tan; Pan, Bin

doi:10.1007/s12204-009-0456-x

Cited by 3 publications

(7 citation statements)

References 1 publication

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“…The measured results of constraint loads on C 1 and C 3 via using the model experiment were acquired based on the Ding, 2004 andYu, 2004. During the physical model experiment, the model scale was set as 1:100 according to the Froude's law of similarity.…”

Section: Results Analysis and Discussionmentioning

confidence: 99%

“…The wave spectrum of Bretschneider and wave angles (incident wave directions) in the numerical simulation (including this paper's simplified method and PFT) are set to the same values as in the physical model experiment reported by Ding, 2004 andYu, 2004. In addition, the shadowing effects of interactions among the columns within CP-VLFS modules for the connector's time-domain hydrodynamic results of constraint loads are considered in this paper's rapid and high-efficiency method and the general PFT.…”

Section: Results Analysis and Discussionmentioning

confidence: 99%

“…Finally, the maximums (Max), means, significant values (SV), and standard deviations (SD) for hydrodynamic constraint loads of C 1 and C 3 based on the aforementioned three methods, including this paper's proposed rapid and high-efficiency estimating method, the PFT by this paper, and the experiment reported by literatures (Ding, 2004 andYu, 2004) (1) The statistical results of hydrodynamic constraint loads estimated by this paper's method for C 1 and C 3 in directions of x, y, and z correspond well with the statistical results of the PFT and the experiment, validating this paper's methodologies.…”

Section: Results Analysis and Discussionmentioning

confidence: 99%

“…Especially, the connectors' constraint loads in directions of y and z present a trend of rapidly decreasing when the wave angles d>85°. The physical model of CP-VLFS (Ding, 2004 andYu, 2004): (A) module; (B) connector.…”

Section: Results Analysis and Discussionmentioning

confidence: 99%

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Hydrodynamic constraint loads estimation on connectors of column-pontoon type very large floating structure (CP-VLFS) under wave stimulation

Han²,

Ji³

et al. 2023

Front. Mar. Sci.

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Column-pontoon type very large floating structure (CP-VLFS) operated at the deep and sea faraway areas are generally exposed to the extremely complex wave conditions. The connectors of CP-VLFS are generally subjected to complicated hydrodynamic constraint loads when the modules of CP-VLFS are stimulated by the long-tern wave forces. The general method for analyzing the hydrodynamic performances for marine floating structures and their components is almost on the basis of potential flow/fluid theory (PFT), but its algorithm principle is relatively complex and would consume plenty of computing time. During the preliminary design and scheme comparison stages for CP-VLFSs, the hydrodynamic results for CP-VLFSs’ modules and their connectors required to be rapidly determined. Hence, a rapid and high-efficiency estimating method for time-domain hydrodynamic constraint loads of connectors on CP-VLFS considering the mathematical and mechanical model of rigid module and flexible connector (RMFC) is developed via this paper. During this estimation method, the Morison theory of floating body is employed to assess the hydrodynamic excitation forces by random and irregular wave (RIW) on CP-VLFS structures, and a series of concise formulas for estimating the hydrodynamic constraint loads of CP-VLFS connectors are derived based on the geometrical relationship of the CP-VLFS modules’ motion. For this paper’s explorations, a three-module CP-VLFS model is considered as a case, and the time-domain hydrodynamic constraint loads of CP-VLFS’s connectors are determined under the RIW stimulations with different wave angles. Hydrodynamic constraint loads of CP-VLFS connectors estimated by this paper agree well with the results of PFT and those of physical experiment, validation the methodologies developed by this paper. Some useful conclusions may provide significant technical supports for hydrodynamic characteristics of CP-VLFS modules and their connectors optimization.

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Section: Results Analysis and Discussionmentioning

confidence: 99%

Section: Results Analysis and Discussionmentioning

confidence: 99%

Section: Results Analysis and Discussionmentioning

confidence: 99%

Section: Results Analysis and Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Hydrodynamic constraint loads estimation on connectors of column-pontoon type very large floating structure (CP-VLFS) under wave stimulation

Han²,

Ji³

et al. 2023

Front. Mar. Sci.

View full text Add to dashboard Cite

show abstract

“…Hybrid bearing possesses many advantages, such as low friction, large carrying capacity, high accuracy, good anti-vibration performance and a long life. It can provide the required hydrostatic force to float the rotor at the starting stage and the hydrodynamic force at the high-speed running stage (Ding, 1989; Meng et al , 2015). However, with the development of the manufacturing industry toward high efficiency and high energy, the precision spindle puts forward a higher demand on the bearing stiffness (Liu and Dong, 2008; Ma et al , 2011; Cun et al , 2015).…”

Section: Introductionmentioning

confidence: 99%

Performance analysis of high-stiffness bearing composited by hydrostatic cavities and tilting pads with preload

Chen

Wang

Yuan

et al. 2018

ILT

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Purpose To meet the high stiffness requirement of bearings used in high-precision spindles, this paper aims to propose a novel kind of bearing composited by hydrostatic cavities and tilting pads with preload. Design/methodology/approach Cavities are cut on the oil seal surface of a hybrid bearing, in which the tilting pads are set up. The load of the bearing is carried by the hydrostatic cavities and tilting pads. The structural features of this compound bearing and the controlling variables of the main stiffness coefficient are presented. Two basic design principles are proposed on the basis of equal machining clearance (EMC) and equal installation clearance (EIC). Findings The theoretical analysis indicates that the stiffness of compound bearings under the EMC condition increases to infinity monotonously when the preload coefficient of the tilting pad tends to 1, while the stiffness under the EIC condition has a peak value. Therefore, a synthetic design principle is proposed by synthetically using the above-mentioned two principles. The applicable range of the three principles is discussed through an example. Originality/value The study about technological combination of hydrostatic cavity and tilting pad in this paper can provide suggestions for the design of a high-stiffness bearing in a precision spindle.

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Research on influencing factors of deformation of hydrostatic thrust bearings

Yu,

Liu,

Zhao

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part J:

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When the hydrostatic thrust bearings operate under conditions of high speed and heavy load, the oil film will be strongly sheared and squeezed, which will increase the temperature of the hydrostatic oil film, resulting in uneven deformation of the workbench and tribology in serious cases. The deformation of the friction pair greatly affects the stability of the workbench during operation, and then affects the machining accuracy. Taking the hydrostatic thrust bearings as the research object, the model of hydrostatic thrust bearings was established based on the fluid–thermosolid coupling theory, and the influencing factors of the deformation of the hydrostatic thrust bearings are analyzed using ANSYS Workbench software, and the influencing laws are discussed. Finally, the correctness of the simulation method is verified by experiments. The results show that the larger the lubricating oil viscosity, the greater the deformation of the guide surface and the oil pad. With the increase in the rotation rate, the deformation of the guide surface and the oil pad increases continuously. With the increase in the inlet flow rate, the deformation of the guide surface and the oil pad is continuously reduced. In engineering practice, on the premise of ensuring the bearings capacity, low-viscosity lubricating oil should be used as much as possible, the rotation rate should be lower, or the inlet flow rate should be increased.

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Discussion on the design value of environmental condition in offshore structure design

Cited by 3 publications

References 1 publication

Hydrodynamic constraint loads estimation on connectors of column-pontoon type very large floating structure (CP-VLFS) under wave stimulation

Hydrodynamic constraint loads estimation on connectors of column-pontoon type very large floating structure (CP-VLFS) under wave stimulation

Performance analysis of high-stiffness bearing composited by hydrostatic cavities and tilting pads with preload

Research on influencing factors of deformation of hydrostatic thrust bearings

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