scholarly journals Mooring System Integrity in Exposed Locations and Narrow Channels

2013 ◽  
Author(s):  
John Flory ◽  
Steve Banfield
Keyword(s):  
High Performance ◽  
Mooring Line ◽  
Mooring Lines ◽  
Narrow Channels ◽  
Wire Ropes ◽  
Line Wear ◽  
System Integrity ◽  
Peak Loads ◽  
High Performance Fiber ◽  
Abrasion Damage

Larger vessels are now being moored at terminals which are exposed to high waves and in channels which are subjected to passing-ship-induced forces. These situations increase mooring line wear and loads and sometimes cause mooring failures. This paper will discuss some of the associated problems and some of the solutions. Use of high-performance fiber ropes instead of wire ropes can decrease mooring loads. These mooring line ropes can be handled by fewer people. The risk of injuries is greatly reduced. When properly cared for, these fiber ropes last longer than wires in service. But fiber ropes are vulnerable to abrasion damage, especially in vessel fairleads. Special nylon fairlead liners are now available to eliminate this wear problem. Fiber rope tails are used on mooring lines to increase stretch and reduce peak loads. Greater vessel motions at exposed location moorings have caused cyclic loading fatigue in nylon tails. Industry recommendations have now been clarified to allow the use of longer nylon tails and of polyester tails. More durable nylon tails are now available. Larger vessels entering into and mooring along confined channels increase the risks of passing ship problems. Passing-ship induced forces increase with vessel size and with the greater speed at which larger vessels must pass in order to maintain steerage. Computer mooring analyses should be conducted to ensure that mooring arrangements are adequate. These analyses should account for effects of waves at exposed locations and should include appropriate passing-ship forces. This paper will be of interest to designers and operators of large vessels and of marine terminals intended for such vessels. Paper published with permission.

Characteristics of Fiber Reinforced Cementitious Composites in Dependence on Casting Direction

2015 ◽  
Vol 732 ◽  
pp. 377-380 ◽  
Author(s):  
Jindřich Fornůsek ◽  
Michal Tvarog
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Cement Composite ◽  
Fiber Reinforced Concrete ◽  
The Other ◽  
Fiber Reinforced ◽  
Peak Loads ◽  
High Performance Fiber ◽  
Reinforced Cement ◽  
Specific Fracture

This paper deals about behavior of fiber reinforced cement composite in dependence on the casting direction. Almost fifty concrete prisms of size 400 x 100 x 100 mm were cast; half of these were fiber reinforced concrete (FRC) and the other half was ultra-high performance fiber reinforced concrete (UHPFRC). Approximately one half of both mixtures was cast in horizontal direction and the other half vertically. It was found that the specific fracture energy of horizontally cast prisms was approximately 4,5 times larger for both materials than the vertically cast ones. Ultimate loads of FRC were very similar for both casting directions. Peak loads of the horizontally cast UHPFRC prisms were approximately 3 times larger than the vertically cast ones. This research confirmed that there is significant influence of the casting direction on the fiber reinforced concrete characteristics.

scholarly journals Numerical Modelling for Synthetic Fibre Mooring Lines Taking Elongation and Contraction into Account

2021 ◽  
Vol 9 (4) ◽  
pp. 417
Author(s):  
Ivan Ćatipović ◽  
Neven Alujević ◽  
Smiljko Rudan ◽  
Vedran Slapničar
Keyword(s):  
Synthetic Fibre ◽  
Steel Wire ◽  
Three Dimensional ◽  
Weight Ratio ◽  
Coupled Model ◽  
Mooring Line ◽  
Outer Diameter ◽  
Mooring Lines ◽  
Wire Ropes ◽  
Coupled Dynamic Analysis

Synthetic fibre mooring lines are used as an alternative to traditional steel wire ropes due to their higher strength to weight ratio. Benefits are also found in relative ease of handling, and therefore the marine industry has largely accepted this type of mooring line. By rules and regulations, the design of mooring lines should be based on a coupled dynamic analysis of a particular mooring system and moored vessel. This approach incorporates damping and inertial forces (i.e., hydrodynamic reactions) acting directly on the mooring lines due to their motion through the seawater. On the basis of the outer diameter of the synthetic fibre rope, the Morison equation gives estimations of the mooring line hydrodynamic reactions. In comparison to the traditional steel wire ropes, the synthetic mooring lines usually have relatively larger elongations and consequently larger reductions of the outer diameter. Furthermore, the lower diameter certainly leads to reduced values of damping and added mass (of mooring lines) that should be considered in the coupled model. Therefore, the aim of this study was to develop a new numerical model that includes diameter changes and axial deformations when estimating the hydrodynamic reactions. The development of the model is carried out with a nonlinear finite element method for mooring lines with the assumption of large three-dimensional motions. The obtained results show the effectiveness of the newly developed model as a more accurate approach in calculation of hydrodynamic reactions.

Influence of technological factors on the properties of ultra-high-performance fiber reinforced concrete

2020 ◽  
pp. 135-147
Author(s):  
Igor Chilin ◽  
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Technological Factors ◽  
High Performance Fiber

Приведены результаты исследований и выполнена оценка влияния технологических факторов на реологические свойства самоуплотняющихся сталефибробетонных смесей, определены кратковременные и длительные физико-механические и деформативные характеристики сверхвысокопрочного сталефибробетона, включая определение его фактической морозостойкости.

scholarly journals Effects of Steel Fiber Percentage and Aspect Ratios on Fresh and Harden Properties of Ultra-High Performance Fiber

2021 ◽  
Vol 2 (3) ◽  
pp. 501-515
Author(s):  
Rajib Kumar Biswas ◽  
Farabi Bin Ahmed ◽  
Md. Ehsanul Haque ◽  
Afra Anam Provasha ◽  
Zahid Hasan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aspect Ratio ◽  
High Performance ◽  
Steel Fiber ◽  
Setting Time ◽  
Fiber Reinforced Concrete ◽  
Future Research ◽  
Manufacturing Cost ◽  
Aspect Ratios ◽  
High Performance Fiber

Steel fibers and their aspect ratios are important parameters that have significant influence on the mechanical properties of ultrahigh-performance fiber-reinforced concrete (UHPFRC). Steel fiber dosage also significantly contributes to the initial manufacturing cost of UHPFRC. This study presents a comprehensive literature review of the effects of steel fiber percentages and aspect ratios on the setting time, workability, and mechanical properties of UHPFRC. It was evident that (1) an increase in steel fiber dosage and aspect ratio negatively impacted workability, owing to the interlocking between fibers; (2) compressive strength was positively influenced by the steel fiber dosage and aspect ratio; and (3) a faster loading rate significantly improved the mechanical properties. There were also some shortcomings in the measurement method for setting time. Lastly, this research highlights current issues for future research. The findings of the study are useful for practicing engineers to understand the distinctive characteristics of UHPFRC.

scholarly journals Transient Responses Evaluation of FPSO with Different Failure Scenarios of Mooring Lines

2021 ◽  
Vol 9 (2) ◽  
pp. 103
Author(s):  
Dongsheng Qiao ◽  
Binbin Li ◽  
Jun Yan ◽  
Yu Qin ◽  
Haizhi Liang ◽  
...  
Keyword(s):  
Service Condition ◽  
Mooring Line ◽  
Mooring System ◽  
Transient Effects ◽  
Floating Platform ◽  
Transient Responses ◽  
Mooring Lines ◽  
Performance Deterioration ◽  
Steady State Responses ◽  
Influence Process

During the long-term service condition, the mooring line of the deep-water floating platform may fail due to various reasons, such as overloading caused by an accidental condition or performance deterioration. Therefore, the safety performance under the transient responses process should be evaluated in advance, during the design phase. A series of time-domain numerical simulations for evaluating the performance changes of a Floating Production Storage and Offloading (FPSO) with different broken modes of mooring lines was carried out. The broken conditions include the single mooring line or two mooring lines failure under ipsilateral, opposite, and adjacent sides. The resulting transient and following steady-state responses of the vessel and the mooring line tensions were analyzed, and the corresponding influence mechanism was investigated. The accidental failure of a single or two mooring lines changes the watch circle of the vessel and the tension redistribution of the remaining mooring lines. The results indicated that the failure of mooring lines mainly influences the responses of sway, surge, and yaw, and the change rule is closely related to the stiffness and symmetry of the mooring system. The simulation results could give a profound understanding of the transient-effects influence process of mooring line failure, and the suggestions are given to account for the transient effects in the design of the mooring system.

scholarly journals High-performance fiber-shaped lithium-ion batteries

2020 ◽  
Vol 92 (5) ◽  
pp. 767-772
Author(s):  
Ye Zhang
Keyword(s):  
Lithium Ion Batteries ◽  
High Performance ◽  
Recent Progress ◽  
Lithium Ion ◽  
Short Review ◽  
Fiber Architecture ◽  
Hybrid Fiber ◽  
High Performance Fiber ◽  
Wearable Products ◽  
Lithium Air Batteries

AbstractThis short review summarizes our recent progress in fiber-shaped lithium-ion batteries and lithium-air batteries based on carbon nanotube hybrid fiber electrodes. The fiber architecture allows batteries to be deformable in all dimensions and bear various deformations such as bending, tying, twisting and even stretching. They are scaled up and further woven into breathable, flexible, stretchable and shape-memory textiles to effectively meet the requirements of modern electronics such as wearable products.

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