scholarly journals EVALUATION OF VIBRATION LEVELS OF THE STERN GEAR WITH OIL LUBRICATION

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.

scholarly journals CALCULATION OF PARAMETRICAL VIBRATIONS OF A SHIP SHAFT LINE SUBJECT TO RIGIDITY OF A STERN BEARING

2017 ◽  
pp. 108-114
Author(s):  
Alexander Alekseevich Migunov ◽  
Victor Andreevich Mamontov ◽  
Aleksey Aleksandrovich Khalyavkin
Keyword(s):  
Dynamic Stability ◽  
Cross Section ◽  
Design Model ◽  
External Loading ◽  
Propeller Shaft ◽  
Shaft Line ◽  
Mathieu’S Equation

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.

Collection and processing of bearing vibration data for their technical condition classification by machine learning methods

2021 ◽  
pp. 10-15
Author(s):  
Ruslan Babudzhan ◽  
Kostiantyn Isaienkov ◽  
Danylo Krasii ◽  
Ruben Melkonian ◽  
Oleksii Vodka ◽  
...  
Keyword(s):  
Machine Learning ◽  
Technical Condition ◽  
Machine Learning Techniques ◽  
Rolling Bearings ◽  
Control Block ◽  
Vibration Data ◽  
Learning Techniques ◽  
Emergency Stop ◽  
Bearing Vibration ◽  
To Receive

An experimental research facility has been developed to receive vibration signals from mechanisms with installed rolling bearings. A control block for all equipment has been created. For the repeatability of the experiment, an external microcontroller with a programmed proportional-integral-derivative regulator was used. Experiments were carried out to obtain initial data for different types of bearings. The processed data were grouped and made publicly available for further research. It is proposed to solve the problem of emergency stop of the generator, arising during operation due to bearings worn, by recognizing the pre-emergency conditions of rotary rig based on the use of advanced machine learning techniques: to highlight the signs of vibration and build clusters according to the degree of worn.

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

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.

scholarly journals PROPELLER SHAFT LINE DYNAMICS AT ACCELERATION MODE

2021 ◽  
Vol 13 (4) ◽  
pp. 548-558
Author(s):  
Sergey N. Tzarenko ◽  
◽  
Alexander N. Rak ◽  
Boris N. Bezlobenko ◽  
◽  
...  
Keyword(s):  
Propeller Shaft ◽  
Shaft Line ◽  
Acceleration Mode

scholarly journals Estimating efficiency of forecasting technical conditions of ship propulsion systems

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.

scholarly journals Determining Time Variation of Cable Tension Forces in Suspended Bridges Using Time-Frequency Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Gannon Stromquist-LeVoir ◽  
Kevin F. McMullen ◽  
Arash E. Zaghi ◽  
Richard Christenson
Keyword(s):  
Frequency Analysis ◽  
Ambient Vibration ◽  
Vibration Measurements ◽  
Cable Tension ◽  
Time Frequency Analysis ◽  
Time Frequency ◽  
Tensile Forces ◽  
Motion Studies ◽  
Ambient Vibration Measurements ◽  
Cable Forces

A feasibility study was conducted to develop a novel method to determine the temporal changes of tensile forces in bridge suspender cables using time-frequency analysis of ambient vibration measurements. An analytical model of the suspender cables was developed to evaluate the power spectral density (PSD) function of a cable with consideration of cable flexural stiffness. Discrete-time, short-time Fourier transform (STFT) was utilized to analyze the recorded acceleration histories in both time and frequency domains. A mathematical convolution of the analytical PSD function and time-frequency data was completed to evaluate changes in cable tension force over time. The method was implemented using acceleration measurements collected from an in-service steel arch bridge with a suspended deck to calculate the temporal variation in cable forces from the vibration measurements. The observations served as proof of concept that the proposed method may be used for cable fatigue life calculations and bridge weigh-in-motion studies.

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