PROPELLER SHAFT LINE DYNAMICS AT ACCELERATION MODE

The paper studies parametrical vibrations of the ship shaft line, which arise because of harmonical change in time of rigidity of a propeller shaft and a stern bearing. The design model of a propeller shaft shows a beam with a cross section constant along its length, which leans on hinged immovable and springy support simulating a stern bearing. At the end of a beam there is a disk simulating a propeller screw. Parametrical vibrations arise due to the external loading and as a result of amortization of the stern bearing. In the analysis of parametrical vibrations of the ship shaft line there are used Mathieu's equation and Strutt-Ince diagram. Dynamic stability of a ship shaft line is defined subject to a gap between a propeller shaft and a stern bearing.

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ASSESSMENT OF IMPACT OF STERN BEARING MATERIAL RIGIDNESS ONTO OPERABILITY OF THE SHIP SHAFT LINE

VESTNIK OF ASTRAKHAN STATE TECHNICAL UNIVERSITY SERIES MARINE ENGINEERING AND TECHNOLOGIES ◽

10.24143/2073-1574-2017-4-80-87 ◽

2017 ◽

pp. 80-87

Author(s):

Igor Olegovich Razov ◽

Guriy Kushner ◽

Victor Andreevich Mamontov ◽

Aleksey Aleksandrovich Khalyavkin

Keyword(s):

Elastic Support ◽

Stiffness Coefficient ◽

Propeller Shaft ◽

Bearing Material ◽

Shaft Line ◽

Transverse Vibrations ◽

Bearing Stiffness ◽

Design Diagram ◽

The Impact ◽

Constant Section

The article considers the dependence of the ship shaft line efficiency on a stiffness coefficient of the material, which stern bearings are made of. The obtained values of a stiffness coefficient used in calculating transverse vibrations of the ship shaft line have been analyzed. The influence of a stiffness coefficient on the value of eigen frequency of transverse vibrations of a propeller shaft has been studied. The design diagram of a propeller shaft is proposed where the propeller shaft is shown as a beam of constant section, which rests upon a hinged immovable and elastic support with a disk on the end. The elastic support models the fodder stern bearing. The influence of the shape of contact of a propeller shaft with a stern bearing onto the load distribution has been estimated. The technique of determining a stiffness coefficient subject to mechanical and geometric parameters of a ship shaft line and its stern bearings has been offered. The impact of a ship shaft line onto the stressed state of the stern bearings and their draft has been studied. The equation of determining a bearing stiffness coefficient has been obtained. There have been given numerical values of a stiffness coefficient of the stern bearing material for certain types of ships.

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Estimating efficiency of forecasting technical conditions of ship propulsion systems

VESTNIK OF ASTRAKHAN STATE TECHNICAL UNIVERSITY SERIES MARINE ENGINEERING AND TECHNOLOGIES ◽

10.24143/2073-1574-2021-4-27-33 ◽

2021 ◽

Vol 2021 (4) ◽

pp. 27-33

Author(s):

Guriy Alekseevich Kushner ◽

Victor Andreevich Mamontov

Keyword(s):

Service Life ◽

Operating Conditions ◽

Technical State ◽

Extrapolation Method ◽

Normal Operation ◽

Propeller Shaft ◽

Shaft Line ◽

Operating Modes ◽

Forecasting System ◽

Vibration Parameters

The article considers an approach to assessing the effectiveness of the most common methods of predicting the technical conditions and failure with reference to the ship shafting. There have been analyzed the main factors in operation of the ship shaft line, which cause the change in its technical state. It has been found that a special feature of some loads acting on the propeller shaft is their stochastic or changing nature over time, which hampers predicting the technical state of the shafting and its units. The features of stochastic and extrapolation forecasting methods have been analyzed. The possibility of using statistical methods in conditions of mass standard production of shafting units with a relatively short regulated service life is estimated. An extrapolation method is proposed for predicting the maximum permissible clearance of stern tube bearings. The case of accumulating samples of measuring results of the propeller shaft sagging in the given time intervals is considered, the approximating functions are constructed. The criteria for the reliability of the results of extrapolation methods for predicting the wear of stern tube bearings are determined. There have been developed the proposals for adapting the causal method as an alternative to the extrapolation method. A schematic diagram of a system for the ship shafting failure predicting has been developed using the registration and analysis of vibration parameters, which serves as the basis for constructing a regression model of damage accumulation. The proposed forecasting system allows studying the actual operating conditions of the shafting, defining the actual external loads and the regularities of their occurrence, measuring deformations and stresses, and determining quantitative indicators of the reliability of the shafting during normal operation and special operating modes, for example, with vibration resonance. The theoretical basis of the algorithm for calculating and registering loads affecting the service life of shafts is proposed.

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EVALUATION OF VIBRATION LEVELS OF THE STERN GEAR WITH OIL LUBRICATION

VESTNIK OF ASTRAKHAN STATE TECHNICAL UNIVERSITY SERIES MARINE ENGINEERING AND TECHNOLOGIES ◽

10.24143/2073-1574-2018-1-74-80 ◽

2018 ◽

pp. 74-80

Author(s):

Vladimir Vasilievich Rodygin ◽

Nikolay Ivanovich Nikolaev ◽

Michail Victorovich Gricenko

Keyword(s):

Frequency Analysis ◽

Technical Condition ◽

Hydrodynamic Resistance ◽

Inspection System ◽

Oil Lubrication ◽

Propeller Shaft ◽

Vibration Measurements ◽

Shaft Line ◽

Bearing Vibration ◽

Periodic Changes

Periodic changes in the torque of the shaft line caused by the engine and uneven hydrodynamic resistance of the propeller are accompanied by vibration of the stern gear. The increased clearance because of loose fit of the stern bearing provokes vibrations of the shaft. With increasing clearance in the stern bearing, lubrication is interrupted, the constant of friction increases, which is accompanied by damage of sliding supports and failure of the bearing. Vibration can result in cracks in the ship's hull and foundation of the support bearings, damage of the stern bearing and the propeller shaft. With systematic measurement of vibration, the frequency analysis obtained allows to determine the nature of the fault and the causes of its occurrence, which greatly improves the reliability of the stern gear and prevents the developing defect. Measuring vibration of ship mechanisms and equipment is described in the Rules of the Russian Maritime Register of Shipping and used actively to monitor the technical condition of ships. The obtained results of vibration measurements are compared to the levels (categories) of the Rules. The ship shaft inspection system, approved by the classification societies, also recommends measuring vibrations of the stern bearings in operation for a modified (without shaft withdrawal) examination of the stern gear, which significantly reduces the costs. Unfortunately, the Rules and requirements do not contain standards for stern gear vibrations, taking into account their design features, which makes impossible to assess the condition of the mechanism. According to the measuring stern gear vibrations onboard the vessels projects 2608 and 1907 and to the comparison of results to the existed standards, there have been collected data for further evaluation of the levels and categories of the stern gear condition.

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Analysis of damage and failure of ship propulsion shafts

VESTNIK OF ASTRAKHAN STATE TECHNICAL UNIVERSITY SERIES MARINE ENGINEERING AND TECHNOLOGIES ◽

10.24143/2073-1574-2021-3-33-39 ◽

2021 ◽

Vol 2021 (3) ◽

pp. 33-39

Author(s):

Guriy Alekseevich Kushner ◽

Victor Andreevich Mamontov ◽

Dmitry Aleksandrovich Volkov

Keyword(s):

Power Systems ◽

Statistical Data ◽

Economic Losses ◽

Propeller Shaft ◽

Ongoing Research ◽

Shaft Line ◽

Damage And Failure ◽

Safety Margins ◽

Russian River

The paper highlights the problem of a ship shaft line failure, which entails significant economic losses, because most vessels of the Russian fleet are equipped with a shaft line. A large number of domestic and foreign works are devoted to studying the causes of damage and failures of ship shafting. The complexity of collecting, systematizing and analyzing statistical data on breakdowns and damages of shafting lies in the fact that the data refer to different periods of time, different periods of operation and types of ships, and are also contained in various sources. There has been considered the approach to systematization of modern statistical data on damages and failures of ship shafting elements collected on the basis of defect-technological lists of the Astrakhan shipyards and from other sources. Information on breakdowns of ships, their elements and ship shaft lines within 2010 - 2019 provided by the Russian River Register of Shipping is given. The analysis of accidents on ships of the class of the Russian Maritime Register of Shipping. The places of occurrence and the nature of the propeller shaft cracks have been established, which makes it possible to assess the nature and magnitude of the destructive loads, as well as the real safety margins. The general classification of the location of the propeller shaft cracks in the order of the frequency of their occurrence is given. There have been shown the results of the analysis of defect-technological lists, which make it possible to establish the causes of ship shafting failures, which led to emergency repair, and the most common defects identified during the scheduled dock repair of ships. The influence of the diameter of propeller shafts on the nature and size of defects, as well as the frequency of their manifestation, is estimated. Based on the results of the analysis, certain measures have been proposed to reduce the number of accidents in shafting of projected vessels, and the most promising directions for improving the already developed structures of shafting in operation are outlined. The results of the analysis are in addition to the ongoing research and development work to improve the reliability of ship power systems.

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Advantages and Experience of Using SSS (Synchro-Self-Shifting) Clutches in Hybrid Propulsion Such As CODELOG or CODELAG Naval Marine Systems

Volume 1: Aircraft Engine; Fans and Blowers; Marine; Honors and Awards ◽

10.1115/gt2019-91873 ◽

2019 ◽

Author(s):

Morgan L. Hendry ◽

Nicholas Bellamy

Keyword(s):

Gas Turbine ◽

Fuel Efficiency ◽

Propeller Shaft ◽

Electric Motors ◽

Propulsion Systems ◽

Hybrid Propulsion ◽

Shaft Line ◽

Advantages And Disadvantages ◽

Mission Success ◽

Ship Performance

Abstract Hybrid marine ship propulsion systems are currently being used, and many more are being considered worldwide, including for commercial ships as well as for navies worldwide. These hybrid propulsion systems offer extended ship range and potentially quiet operation with propulsion on propeller shaft line electric motors. When high power and / or speed may be required, the main engines or turbines can be quickly started, and propeller shaft line clutches provide quick and reliable transition from or back to the electric motors. In the naval marine sector, several ship programs currently use “Combined Diesel Electric or Gas Turbine” (CODELOG) or “Combined Diesel Electric and Gas Turbine” (CODELAG) propulsion. Some utilize Synchronous Self-Shifting Clutches, and some utilize other types of non-automatic friction clutches. Many navies worldwide are considering this type of hybrid propulsion, but variations in machinery arrangements and components can result in significant differences in fuel efficiency, weight, space, first time cost, ship performance, and propulsion machinery lifecycle maintenance with associated cost. Therefore, serious investigation of the alternatives early in the ship design phase is important and accessing the experience of these existing systems with these components is vital, before settling on a machinery arrangement and its components for a future ship program. As the old cliché says, “The Devil is in the Details!” Like any system, the success, the reliability, and the ultimate capability often come down to design details and the components chosen. Naval ships are designed to operate, even when damaged or when control or oil supply systems fail. Simplicity and the ability to improvise is often the key to mission success or failure. Synchronous Self-Shifting Clutches, or SSS Clutches, have proven to be “fit and forget” in these propulsion systems, have performed without fail in battle conditions, and this paper will describe the systems, explore the alternatives for propulsion clutches, provide advantages and disadvantages, and will provide experience of SSS Clutches in hybrid propulsion systems.

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Application of Shape Memory Alloys in Pipeline Couplings for Shipbuilding

Polish Maritime Research ◽

10.2478/pomr-2020-0049 ◽

2020 ◽

Vol 27 (3) ◽

pp. 82-88

Author(s):

Leszek Matuszewski

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

Free Space ◽

Propeller Shaft ◽

Space Applications ◽

Shaft Line ◽

Line Coupling ◽

Technological Interest

AbstractThe aim of the study is to analyse shape memory alloy (SMA) pipeline joints in limited space applications for all kinds of ships. Generally, the space available in various areas on ships is strictly limited and service works usually meet many obstacles. If we consider a pipeline, the flange joints always require a larger free space around the pipe than the pipe alone. A simultaneous problem can occur with the propeller shaft line coupling between bearings. SMA couplings require less space around the pipe and service should be easier, e.g., insulation fixing, painting and so on. SMA couplings last for a lifetime and there is no need for periodical seal replacement. Herein, some proposals among other unpublished data are discussed. There is a significant technological interest in the use of SMAs for applications not widely used yet. A wide variety of alloys present the shape memory effect and many generate an expressive restitution force considerable for commercial interests.

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