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 Evaluation of influence of elastic properties of slide bearing of ship stern gear on stiffness coefficient

2020 ◽  
Vol 2020 (1) ◽  
pp. 83-93
Author(s):  
Aleksey Aleksandrovich Khalyavkin ◽  
Sergey Aleksandrovich Makeev ◽  
Dmitry Vladimirovich Loshadkin ◽  
Victor Andreevich Mamontov ◽  
Salamekh Ali ◽  
...  
Keyword(s):  
Natural Frequency ◽  
Experimental Studies ◽  
Resonance Phenomenon ◽  
Stiffness Coefficient ◽  
Complex Dynamic ◽  
Bearing Material ◽  
Bending Vibrations ◽  
Shaft Line ◽  
Slide Bearing ◽  
Transverse Vibrations

The article considers the ship shaft line as a complex dynamic system influencing the operation of the ship. There has been given a diagram of the shaft line with one stern bearing and one remote bearing of the propeller shaft. The shaft line service life depends on the material of the slide bearing of the stern gear (lignum vitae, babbitt, textolite, caprolon, bronze, polyurethanes, rubber). The analysis of the research of static and dynamic calculations of ship shafting has been carried out. The design scheme of the ship shafting on elastic point supports is presented. It has been referred to consider feasibility of the elastic and mechanical properties of stern bearings at the stage of designing a ship shaft line. The method of calculating the transverse vibrations of the shaft line is studied, the purpose of which is to determine the natural frequency. The formula for calculating the lowest natural frequency of bending vibrations is given. The results of experimental studies at the KMV-200 stand based on uneven distribution of loads along the stern bearings are considered. It has been suggested that the greater the wear, the lower the stiffness coefficient. At a certain degree of wear of stern bearings, a resonance phenomenon occurs at the lowest operating frequencies. The value of the stiffness coefficient is studied depending on the modulus of elasticity of the stern bearing material. Static analysis of the ship shaft line was made taking into account the stiffness coefficient of the stern bearing. The universal equation of the curved axis of the beam is used according to the initial parameters method. As it has been found, the greater the deflection at the propeller attachment point, the lower the natural frequency of the transverse vibrations of the shaft line. In calculations it is necessary to take into account the separation of the shaft line from the stern bearing, since it helps to reduce the natural frequency and the appearing resonance during transverse vibrations.

scholarly journals INFLUENCE OF INCONSTANT DISTRIBUTION OF DEADWOOD BEARING STIFFNESS COEFFICIENTON NATURAL FREQUENCY OF THE SHAFT TRANSVERSE VIBRATIONS

2019 ◽  
pp. 89-96
Author(s):  
Guriy Kushner ◽  
Victor Andreevich Mamontov
Keyword(s):  
Differential Equation ◽  
Distribution Function ◽  
Uniform Distribution ◽  
Natural Frequency ◽  
Stiffness Coefficient ◽  
Propeller Shaft ◽  
Shaft Length ◽  
Slide Bearing ◽  
Transverse Vibrations ◽  
Stiffness Distribution

One of the most significant factors affecting the natural frequency of transverse vibrations of shaft-slide bearing systems is the stiffness coefficient of the slide bearing. The need to consider the influence of heterogeneity of stiffness coefficient of the bearing on its natural frequency is caused by the fact that when the bearing is worn, the modulus of longitudinal elasticity of the material changes, and since the bearing wears unevenly, the non-uniform distribution of the stiffness coefficient occurs. The problem of determining the natural frequency of transverse vibrations of a ship propeller shaft based on the foundation with a variable stiffness coefficient along the length has been studied. The differential equation of the propeller shaft vibrations written taking into account the stiffness coefficient variable along the shaft length is considered. It has been noted that, in the general case, this equation is a fourth-order partial differential equation and cannot be integrated in quadratures for an arbitrary stiffness distribution function along the shaft length. A numerical-analytical method for determining the natural frequency of a system based on approximation of the stiffness distribution function by a piecewise-linear function is proposed. The method is applied to calculate the natural frequencies of the pipeline section taking into account the functions describing the change in the stiffness coefficient. The proposed method allows to consider the section of the shafting enclosed in the stern bearing, subject to the non-uniform distribution of the stiffness coefficient of the bearing, and is the basis for improving the accuracy of finding the true natural frequency of transverse vibrations of the shafting.

scholarly journals Influence of bearing material and clearance in a stern device on transverse vibrations parameters of a ship shaft model

2019 ◽  
Vol 2019 (4) ◽  
pp. 107-113
Author(s):  
Гурий Кушнер ◽  
Guriy Kushner ◽  
Виктор Андреевич Мамонтов ◽  
Victor Andreevich Mamontov
Keyword(s):  
Frequency Converter ◽  
Operating Experience ◽  
Coefficient Of Determination ◽  
Dynamic Strain ◽  
Unstable State ◽  
Bearing Material ◽  
Technical Problems ◽  
Shaft Line ◽  
Shaft System ◽  
Transverse Vibrations

The operating experience of the large-capacity vessels shafting illustrates a number of new technical problems, such as an increase in the number of accidents caused by damage to stern devices. A significant number of accidents associated with breakdowns of the propeller shafts due to exceeding the cyclic strength of their material, suggests the need for further study of the vi-brations of the shafting system. The creation of an experimental installation on the basis of the la-boratory of the ship shaft line of Astrakhan State Technical University provided experimental data under controlled test conditions. The design and operation principle of the experimental setup, which simulates the oscillations of a rotating shaft line model using various materials of shafts and bearings have been studied. The installation is a model of a ship shaft system, the shaft system of which is driven by an asynchronous electric motor. The speed of the shaft system can be adjusted using a frequency converter. Measurement and registration of vibrations is carried out using a hardware-software complex by the method of dynamic strain gauging. There have been shown the results of an experimental study of the parameters of transverse vibrations of a ship shaft model for various material of a stern bearing model and clearance in a stern device. The obtained dependences are represented by the Lagrange interpolation polynomial and response functions in the form of a second-order polynomial. Verification of the compliance of the regression model of data variability was carried out using a multiple coefficient of determination. Bearing material and clearance in a stern device have a significant effect on the frequency of the onset of an unstable state of the installation shaft. The research results can be used in the calculation of transverse vibrations of ship shaft lines.

Influence of non-ideal storage conditions on carrot moisture content loss

2008 ◽  
Vol 4 (1) ◽  
pp. 61-75 ◽  
Author(s):  
Tímea Kaszab ◽  
Ferenc Firtha ◽  
András Fekete
Keyword(s):  
Moisture Content ◽  
Cutting Force ◽  
Storage Conditions ◽  
Stiffness Coefficient ◽  
Mass Reduction ◽  
Good Characteristic ◽  
Specific Cutting Force ◽  
Color Characteristics ◽  
The Impact

The objective of the work reported here was to determine changes in the moisture content, firmness characteristics, color attributes and NIR absorbance of two carrot cultivars during storage. There was a definite loss in the moisture content that caused changes in the firmness. This result shows that carrot firmness is very sensitive to the moisture content. The firmness — especially the cutting force — is a good characteristic for predicting changes in carrot moisture content during storage. The color characteristics — a* and b* — showed a slight change in the function of the moisture content. However, these color characteristics are suitable for distinguishing the phloem and xylem parts of carrot cultivars. There were not found definite changes in the NIR absorbance as the function of the moisture content. Consequently, the specific cutting force and the impact stiffness coefficient are good characteristics of the carrot moisture content and the mass reduction during storage under non-ideal conditions.

The Impact of Different Axial Oil Chamber Design on Hydrostatic Spindle

2015 ◽  
Vol 789-790 ◽  
pp. 296-299
Author(s):  
Shao Hsien Chen ◽  
Shang Te Chen ◽  
Chien Cheng Hsu
Keyword(s):  
High Precision ◽  
Large Scale ◽  
Development Trend ◽  
Ball Screw ◽  
Precision Machining ◽  
Radial Clearance ◽  
Axial Stiffness ◽  
Key Technologies ◽  
Bearing Stiffness ◽  
The Impact

High-precision machining and large-scale tool are the most primary development trend of current machine tool and hydrostatic products are key technologies of high-precision machining equipments. However, these equipments mostly process miniature components, thus the adopted tools are relatively small and the spindles mainly use are mainly built-in types of HSK32 to HSK25 with revolutions speed over 25,000rpm. Some processing equipments are even equipped with hydrostatic or gas-static spindles. The study extends the axial oil chamber to radial ones to expand the action area of axial oil pressure and form a closed oil seal edge by combining the radial clearance. Consequently, the axial bearing stiffness can be enhanced to enlarge the application scope of hydrostatic spindle. The design mode can enhance axial stiffness of spindle modules or strengthen the stiffness of hydrostatic spindle in a ball screw.

An Impact Analysis of Turbine Guide Bearing Stiffness on Rotating Parts’ Transverse Vibration Characteristics

2011 ◽  
Vol 117-119 ◽  
pp. 222-230
Author(s):  
Yi Zhu ◽  
Xi De Lai ◽  
Li Fa Wang
Keyword(s):  
Large Scale ◽  
Impact Analysis ◽  
Hydraulic Turbine ◽  
Calculation Model ◽  
Vibration Characteristics ◽  
Francis Turbine ◽  
Lateral Vibration ◽  
The Finite Element Method ◽  
Bearing Stiffness ◽  
The Impact

A vibration calculation model for a large-scale hydraulic turbine group is built to act on the unbalanced force between the rotor and the runner. Take the Francis turbine group for example. Using the finite element method, the units lateral vibration characteristics of rotating components were calculated and analyzed. The paper discusses the impact of location and the guide bearing stiffness on the lateral vibration characteristics of the unit. Based on the elastic supporting models, the paper also compares the results of the guide bearing stiffness modified simultaneously and respectively. Results show that the guide bearing stiffness has a significant impact on the lateral vibration characteristics of the location of the unit, which provides a reference for the reduction of vibration and the optimization of the supporting structure of the turbine unit.

Improvement of Wind Speed Measurement Model by Meteorological UAV and System Design

2012 ◽  
Vol 542-543 ◽  
pp. 591-594
Author(s):  
Shu Dao Zhou ◽  
Yong Qi Jin ◽  
Ying Qiang Wang ◽  
Min Wang
Keyword(s):  
Wind Speed ◽  
System Design ◽  
Measurement System ◽  
Measurement Model ◽  
Calculation Model ◽  
Related Data ◽  
Speed Measurement ◽  
Design Diagram ◽  
Wind Speed Measurement ◽  
The Impact

At present, the error of wind speed measurement by meteorological UAV is great, in order to solve this problem, this paper identified the major sources of error by the analysis of the wind measurement model. Found that the airspeed error caused by the aircraft acceleration for the airspeed is very small, so classic airspeed measurement calculations often ignore the impact of aircraft acceleration, but the value of wind speed is smaller, so that the error caused by aircraft acceleration relative to the wind speed cannot be ignored. Therefore, this article added aircraft acceleration to re-establish the airspeed measurement model, and got an improved wind speed of calculation model. In order to verify the model, the wind speed measurement system was been designed, the system design diagram and related data processing, solver method were presented.

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.

scholarly journals ANALYSIS OF TECHNICAL FAILURES ON FISHING VESSELS IN THE FAR EAST

2019 ◽  
pp. 48-55
Author(s):  
Igor Petrovich Turishchev ◽  
Mikhail Vladimirovich Gomzyakov ◽  
Oleg Vladimirovich Moskalenko ◽  
Anatoliy Nickolaevich Sobolenko
Keyword(s):  
Human Factor ◽  
Far East ◽  
Electrical Equipment ◽  
Technical Equipment ◽  
Shaft Line ◽  
Fishing Vessels ◽  
The Far East ◽  
Force Majeure ◽  
Automation Systems ◽  
The Impact

The article focuses on the main factors influencing the safety of navigation, such as natural factors, man-made impact, depreciation aspect, operational impact and human factor. The analysis of marine accidents in the far East region determined the value of its technical component. The statistics of the machinery failures on fishing vessels is given. One out of ten accidents has been stated to occur as a result of force majeure events, three quarters of the accidents are related to the human factor in the form of personnel erroneous actions, the rest happen due to technical imperfection of the ships. The chart shows the distribution of accidents by years due to failures and breakdowns of ship technical equipment given in percentage figures. Breakdowns of the main engines, auxiliary mechanisms and their elements, including their systems, annually make up 33.9 - 40.7% of the total number of accidents. Characteristic failures of ship technical equipment are: breakdowns of the main engines, auxiliary diesel generators, auxiliary mechanisms, electrical equipment, screw-steering complex with the shaft line, automation systems. Statistics of the causes of breakdowns of propulsion plant, auxiliaries, main systems and their elements is proportional to the data of similar studies. An attempt has been made to evaluate the importance of the operator-machine link at all levels of responsibility for coastal personnel and ship crews. The impact on the man-machine link in the whole chain of operation of the vessel is important; thus, there was set a task to carry out a quantitative investigation of the reliability of this link. In terms of the ergotechnical component of the fishing fleet operation there has been substantiated the necessity of developing measures (technical, economic, informational, legal) to improve the quality of the vessel activity.

scholarly journals Nonlinear Pounding Analysis of Multispan and Simply Supported Beam Bridges Subjected to Strong Ground Motions

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Hong-Yu Jia ◽  
Xian-Lin Lan ◽  
Nan Luo ◽  
Jian Yang ◽  
Shi-Xiong Zheng ◽  
...  
Keyword(s):  
Finite Element ◽  
Parameter Analysis ◽  
Cross Sectional ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
Finite Element Software ◽  
Impact Element ◽  
Bearing Stiffness ◽  
The Impact ◽  
Gap Width

To investigate the nonlinear impact effect of multispan simply supported beam bridges under strong earthquakes, firstly, the dynamic motion equation, the algorithm of its solution, and some pounding modelling methods are presented and the finite element model of a considered multispan simply supported railway beam bridge is established in the nonlinear finite element software of SAP2000 in which the primary nonlinear characteristics of the bearing and the impact element are considered herein. Secondly, the natural vibration characteristic of the considered railway bridge is analyzed to prepare for the subsequent parameter analysis. Finally, the influence of three nonlinear parameters, i.e., stiffness of impact element, separation gap width of expansion joint, and bearing stiffness, on impact responses of bridge structures is studied. The results show that the first several modes of multispan simply supported beam bridges are mainly longitudinal and vertical vibrations. Under longitudinal seismic excitations, the large longitudinal displacement response is induced possibly and results in the collision or even unseating of superstructures at the expansion joints and abutments. The influence of separation gap width between adjacent decks on the pounding effect of bridges is greater than that of collision stiffness originated from the pounding modelling element. The impact force and pounding number run up to the maximum conditional on the collision stiffness of 9.9 × 109 (N/m) and the separation gap width of 0.14 (m). The bearing stiffness affects significantly the displacement of the pier top and the cross-sectional internal force at the bottom of piers but has little effect on the collision force and number.

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