scholarly journals INFLUENCE OF MATERIAL OF DEADWOOD BEARINGS ON FREQUENCY OF CROSS FLUCTUATIONS OF THE SHIP SHAFT LINE

2018 ◽  
pp. 24-30
Author(s):  
Dmitry Vladimirovich Loshadkin ◽  
Anna Yakovlevna Auslender ◽  
Denis Olegovich Shatskov ◽  
Victor Andreevich Mamontov ◽  
Aleksey Aleksandrovich Khalyavkin
Keyword(s):  
Elastic Support ◽  
Geometrical Parameters ◽  
Axial Loads ◽  
Concentrated Load ◽  
Load Model ◽  
Shaft Line ◽  
System Service ◽  
Operation Process ◽  
Operational Characteristics ◽  
Rigidity Coefficient

The article describes the ship shaft line which is a constructive complex linking kinematically the main propulsion engine to the thruster and designed to pass torque moments and axial loads, appearing in the operation process of the ship propulsion system. Service life of the ship shaft line depends on operational condition of stern bearings in the shaft tube, that is why they should have high resistance against actual loads and preserve operational characteristics. There is studied the influence of elastic properties of stern bearings on numerical value of eigen frequency under cross oscillations if the ship shaft line. Assessment of influence of the deadwood bearing material on the rigidity coefficient is made. The settlement scheme for studying cross fluctuations represents a beam with constant cross section that leans on one hinged immovable elastic support with a rigidity coefficient c . At the end of a beam there is a concentrated load. The elastic support and the concentrated load model the stern bearing and the propeller screw, respectively. The technique of determining the rigidity coefficient subject to mechanical and geometrical parameters of the ship shaft line and its deadwood bearings is described. The importance of the numerical value of the rigidity coefficient of different materials of plugs of deadwood bearings when calculating cross fluctuations of the ship shaft line has been estimated. The real ship shaft line is investigated.

scholarly journals STUDYING THE INFLUENCE OF MECHANICAL AND ELASTIC PROPERTIES OF DEADWOOD BEARINGS ON RIGIDITY COEFFICIENT NUMERICAL VALUE

2019 ◽  
pp. 71-79
Author(s):  
Sergey Aleksandrovich Makeev ◽  
Victor Andreevich Mamontov ◽  
Aleksey Aleksandrovich Khalyavkin ◽  
Denis Olegovich Shatskov
Keyword(s):  
Geometrical Parameters ◽  
Relative Deformation ◽  
Stress Increment ◽  
Elastic Parameters ◽  
Pilot Studies ◽  
Design Models ◽  
Shaft Line ◽  
Rigidity Coefficient ◽  
Bearing Rigidity ◽  
Elastic Characteristics

The article studies the influence of a rigidity coefficient of the elastic supports and a foundation, which simulate deadwood bearings in the design models, on the stress-strain state of the ship shaft line. The importance of a rigidity coefficient in designing the ship shaft line and its elements has been specified. In the analysis the rigidity coefficient is taken as a constant value. Elastic characteristics of the stern bearing bushings may greatly affect the parameters of the designed shaft lines. Generally, the stern bearings are made of caprolon, pockwood, babbit and rubber. There has been presented a design model of the ship shaft line on elastic point support. It has been stated that the value of the rigidity coefficient is specified in many works when calculating the ship shaft line, but there is no reference to the sources and methods of receiving it. The overall view of the deformed contact of the shaft with stern bearing has been illustrated. The technique of determining the rigidity coefficient has been offered, subject to mechanical and geometrical parameters of the ship shaft line and its deadwood bearings. The equation of defining the stern bearing rigidity coefficient has been produced, which helps to account the elastic parameters of the bushings and geometry of contact of the ship shaft line with the bushing. For reliability of the offered technique a number of pilot studies on the hydropress П-125 were conducted, for which there were manufactured special devices and a mandrel. The essence of method of determining a rigidity module, according to GOST 9550-81, is in measuring the ratio of stress increment to a corresponding increment of relative deformation of compression. It was proved that the divergence of the values of rigidity coefficient received by the experimental and theoretical ways does not exceed 8%.

Carcass Tear Out Load Model for Multi-Layer Pressure Sheath Risers

2014 ◽  
Author(s):  
Claus Egebjerg Kristensen ◽  
Jan Muren ◽  
Geir Skeie ◽  
Håvard Skjerve ◽  
Nils Sødahl
Keyword(s):  
Probability Of Failure ◽  
Simulation Approach ◽  
Axial Loads ◽  
Contributing Factors ◽  
Load Model ◽  
General Terms ◽  
Polymer Properties ◽  
Flexible Risers ◽  
Key Driver ◽  
Gravity Component

Recent failures of multi-layer pressure sheath risers have shown that the carcass may fail in the top termination due to excessive axial loads. This is a new failure mode for flexible risers, recently presented by the authors in more general terms. The present paper explains details of the established load model and the validation against mid-scale tests, risers failed during operation, and operating risers close to failure by this new mode. The key driver in the model is the temperature contraction of pressure sheath layers. Also influenced by changes in polymer properties over the operational history, temperature and time is explained. Other contributing factors in the load model are gravity-component and bore pressure. The prediction model for the carcass loads are developed during Statoils investigation in 2011–12. The model is regarded representative for 20% of the most exposed risers. Several of the input parameters are uncertain and a Monte Carlo simulation approach is selected to study the variability and predict the probability of failure, given that radial contact pressure is sufficiently low. The approach adopted in the model may be applicable to other risers where polymers and steel components act together, and in such circumstances act as a guide for alternative model developments.

scholarly journals The Influence of the Load Model and other Parameters on the Dynamic Behavior of Curved-in-Plane Bridges

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Ioannis G. Raftoyiannis ◽  
George T. Michaltsos
Keyword(s):  
Dynamic Behavior ◽  
Moving Load ◽  
Curvature Radius ◽  
Vehicle Speed ◽  
Continuum Approach ◽  
Theoretical Formulation ◽  
Concentrated Load ◽  
Load Model ◽  
Mass Load ◽  
Real Vehicle

AbstractThis paper deals with the dynamic behavior of curved-in-plane bridges where the effect of the bridge curvature radius, the moving load (vehicle) speed, the truck cant angle, the deck surface conditions and, mainly, the response accuracy depending on the vehicle model used are investigated. Besides the above parameters, the influence of several loading models is studied as well, especially the models of a concentrated load, a damped mass-load, a sequence of two concentrated loads and a real vehicle aswell as a damped vehicle,where its width is taken into account. A 3-DOF model is considered for the analysis of the bridge, while the theoretical formulation is based on a continuum approach, which has been widely used in the literature to analyze such bridges.

Tunable-focus liquid lens actuated by a novel piezoelectric motor

2020 ◽  
pp. 095440622097166
Author(s):  
Hanlu Li ◽  
Weihao Ren ◽  
Lin Yang ◽  
Chengcheng Ma ◽  
Siyu Tang ◽  
...  
Keyword(s):  
Low Cost ◽  
Geometrical Parameters ◽  
Vertical Force ◽  
Piezoelectric Motor ◽  
Mobile System ◽  
Compact Structure ◽  
Liquid Lens ◽  
Operation Process ◽  
Near Future ◽  
Lens Surface

In this paper, a tunable-focus liquid lens driven by a novel piezoelectric motor is proposed for the adaptive application. Compressing the liquid chamber, the curvature of the lens can be changed by increasing the liquid pressure. This mechanism requires the motor to provide a vertical force to deform the lens surface, whose curvature can be decreased and thereby increasing its focus. As a key part of the tunable-focus liquid lens, a novel piezoelectric motor with the compact structure is emphatically developed in this paper. The operation process of the motor is discussed in detail, whose geometrical parameters are calculated by the finite element simulations. And the motor prototype is then fabricated and tested by the experimental platform. The testing results indicate that the motor can operate steadily and continuously, whose maximum linear velocity can reach 0.065 mm/s under the frequency of 11.80 kHz and voltage of 400 [Formula: see text]. The measurement shows that the proposed lens driven by the piezoelectric motor can zoom ranged from 9.6 mm to 17.9 mm, which is suitable for adaptive eyeglass application. Compared with other liquid lens, the prototype with a compact structure, easy and low cost fabrication process can provide high-precision adjustment within a certain range. The presented device exhibits well zooming characteristic and stability in the experiment, which also realizes the successful application of piezoelectric motor in the liquid-lens. It shows greatly potential in the adaptive eyeglasses, and may be employed as the mobile system in the near future.

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.

Geometrical Parametric Study and Development of Design Formulae for the SCF Distribution Along the Weld Toe in Multi-Planar CHS DKT-Connections of Offshore Structures

2011 ◽  
Author(s):  
Mohammad Ali Lotfollahi-Yaghin ◽  
Hamid Ahmadi ◽  
Sajad Shahverdi
Keyword(s):  
Offshore Structures ◽  
Geometrical Parameters ◽  
Axial Loads ◽  
Geometrical Properties ◽  
Fatigue Design ◽  
Assessment Study ◽  
Wide Range ◽  
Weld Toe ◽  
Complete Set ◽  
The Uk

In the present paper, effects of geometrical parameters on the SCF distribution along the weld toe of multi-planar tubular DKT-joints under the axial loads are investigated. In order to study the multi-planar effect, SCF distribution in multi-planar joints is compared with the distribution in a uni-planar joint having the same geometrical properties. Based on the multi-planar DKT-joint FE models which are verified against experimental results and the predictions of Lloyd’s Register (LR) equations, a complete set of SCF database is constructed. The FE models cover a wide range of geometrical parameters. Through nonlinear regression analysis, a new set of SCF parametric equations is established for the accurate and reliable fatigue design of multi-planar DKT-joints under axial loads. An assessment study of these equations is conducted against the experimental data and the acceptance criteria recommended by the UK DoE.

On the Unbonded Contact Between Plates and an Elastic Half Space

1969 ◽  
Vol 36 (2) ◽  
pp. 198-202 ◽  
Author(s):  
Y. Weitsman
Keyword(s):  
Approximate Solution ◽  
Tensile Stress ◽  
Half Space ◽  
Elastic Plate ◽  
Elastic Half Space ◽  
Elastic Support ◽  
Elastic Region ◽  
Concentrated Load

In this paper an approximate solution is presented for the radius of contact between an elastic plate and a semi-infinite elastic half space. The plate is assumed to rest on the supporting half space without bond, and to be pressed against the elastic region by a concentrated load. In the absence of bonding no tensile stress can be transmitted across the interface between the plate and its elastic support so that contact takes place only within a circle centered about the concentrated load. Outside of this circle the plate lifts up and is no longer in contact with the elastic region.

Analytical solution to the elastic bending of long and rectangular thin plate resting on rubber foundation

2011 ◽  
Vol 226 (5) ◽  
pp. 1186-1197 ◽  
Author(s):  
M Mehrara ◽  
M J Nategh ◽  
H M Naeeni
Keyword(s):  
Mechanical Model ◽  
Contact Region ◽  
Closed Form Solution ◽  
Form Solution ◽  
Geometrical Parameters ◽  
Rectangular Thin Plate ◽  
Concentrated Load ◽  
Elastic Bending ◽  
System A ◽  
Numerical Analytical Method

In this study, the elastic bending of long and rectangular plate resting on unilateral rubber foundation under a concentrated load has been investigated. A new continuum model has been developed to study the rubber foundation reaction. A simplified one-parameter model could thus be obtained for the foundation reaction permitting the parameter to be directly determined without resorting to trial estimation. The governing differential equations have been derived for the plate–foundation system. A numerical–analytical method has been proposed for the exact and closed-form solution of the equations. Several examples have been presented in order to draw a comparison between the results of the proposed solution and the conventional numerical solution. The results have also been compared with the Winkler's mechanical model. Finally, the effect of various parameters on the behaviour of the plate–foundation system has been studied. The results indicate that the length of contact region between the plate and the foundation is influenced by the mechanical and geometrical parameters of the plate and also on the foundation modulus but does not depend on the loading.

scholarly journals Analysis of boundary conditions in design circuits influence on the shaft line operating state

2020 ◽  
Vol 217 ◽  
pp. 03006
Author(s):  
Alexei Khalyavkin ◽  
Sergey Makeev ◽  
Ali Salamekh ◽  
Aleksandra Ivanovskaya
Keyword(s):  
Boundary Conditions ◽  
Weight Bearing ◽  
Performance Criterion ◽  
Concentrated Load ◽  
Elastic Supports ◽  
Shaft Line ◽  
Design Scheme ◽  
Shaft System ◽  
Action Point ◽  
The One

The work investigates the bearing piece boundary conditions influence on the shaft line operating state, with respect to elastic properties of stern-tube bearings. It is noted that the shaft line is a part of the ship’s power plant and it is a shaft system, located on the same axis. Performance criterion is the deflection of the concentrated load in the design scheme`s action point, modeling the propeller`s weight, bearing parts reactions and the natural frequency of linear lateral oscillations. The design scheme itself is a beam, resting on two elastic supports with a k stiffness factor, with concentrated load acting on the one end and three variants of the boundary conditions: pinched, hinged and sliding supports on another one. The results of calculations are given for different boundary conditions and the stiffness factors of elastic supports. The diagram of natural frequencies of linear lateral oscillations of ship`s shafting line is presented.

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