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%.

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.

Cyclone with Controlled Parameters and Self-Emptying Bin for Air Dedusting in Machine Building Plants

2014 ◽  
Vol 682 ◽  
pp. 46-52 ◽  
Author(s):  
B.Ch. Meskhi ◽  
Y.I. Buligin ◽  
L.N. Alexeenko
Keyword(s):  
Engineering Calculation ◽  
Machine Building ◽  
Calculation Procedure ◽  
Flue Gases ◽  
Geometrical Parameters ◽  
Pilot Studies ◽  
Constructive Solution ◽  
Technological Processes

Efficiency of the dedusting of flue gases of the technological processes is reached at the expense of the new constructive solution of the cyclonic device in which possibility of the regulation of its geometrical parameters depending on properties and characteristics of the air-and-coal environment is provided. Results of pilot studies are presented, the engineering calculation procedure and a choice of the sizes of such devices is developed

scholarly journals Learning inexpensive parametric design models using an augmented genetic programming technique

2006 ◽  
Vol 20 (1) ◽  
pp. 1-18 ◽  
Author(s):  
PETER C. MATTHEWS ◽  
DAVID W.F. STANDINGFORD ◽  
CARREN M.E. HOLDEN ◽  
KEN M. WALLACE
Keyword(s):  
Genetic Programming ◽  
Parametric Design ◽  
Design Parameters ◽  
Simple Extension ◽  
Geometrical Parameters ◽  
Analysis Tool ◽  
Design Data ◽  
Programming Technique ◽  
Design Models ◽  
Design Variables

Previous applications of genetic programming (GP) have been restricted to searching for algebraic approximations mapping the design parameters (e.g., geometrical parameters) to a single design objective (e.g., weight). In addition, these algebraic expressions tend to be highly complex. By adding a simple extension to the GP technique, a powerful design data analysis tool is developed. This paper significantly extends the analysis capabilities of GP by searching for multiple simple models within a single population by splitting the population into multiple islands according to the design variables used by individual members. Where members from different islands “cooperate,” simple design models can be extracted from this cooperation. This relatively simple extension to GP is shown to have powerful implications to extracting design models that can be readily interpreted and exploited by human designers. The full analysis method, GP heuristics extraction method, is described and illustrated by means of a design case study.

Offender-nightmares: Two pilot studies.

Dreaming ◽  
2018 ◽  
Vol 28 (2) ◽  
pp. 140-149
Author(s):  
Jonas Mathes ◽  
Monika Renvert ◽  
Christian Eichhorn ◽  
Simon Freiherr von Martial ◽  
Annika Gieselmann ◽  
...  
Keyword(s):  
Pilot Studies

The Maastricht Cohort Study on Fatigue and Psychological Distress at Work: Pilot Studies of the Questionnaire

1999 ◽  
Author(s):  
Ute Bultmann ◽  
Anna J. H. M. Beurskens ◽  
IJmert Kant ◽  
Gerard M. H. Swaen
Keyword(s):  
Cohort Study ◽  
Psychological Distress ◽  
Pilot Studies

Job content questionnaire 2.0: Results of multi-country pilot studies and final new scale decisions

2013 ◽  
Author(s):  
R. Karasek ◽  
W. Agbenyikey ◽  
M. Dollard ◽  
M. Formazin ◽  
J. Li ◽  
...  
Keyword(s):  
Pilot Studies ◽  
Job Content Questionnaire ◽  
Job Content

Bulk drag coefficient of a subaquatic vegetation subjected to irregular waves: Influence of Reynolds and Keulegan-Carpenter numbers

2020 ◽  
pp. 34-42
Author(s):  
Thibault Chastel ◽  
Kevin Botten ◽  
Nathalie Durand ◽  
Nicole Goutal
Keyword(s):  
Drag Coefficient ◽  
Wave Height ◽  
Wave Attenuation ◽  
Empirical Relationship ◽  
Breaking Waves ◽  
Irregular Waves ◽  
Geometrical Parameters ◽  
Flume Experiments ◽  
Seagrass Meadows ◽  
Artificial Vegetation

Seagrass meadows are essential for protection of coastal erosion by damping wave and stabilizing the seabed. Seagrass are considered as a source of water resistance which modifies strongly the wave dynamics. As a part of EDF R & D seagrass restoration project in the Berre lagoon, we quantify the wave attenuation due to artificial vegetation distributed in a flume. Experiments have been conducted at Saint-Venant Hydraulics Laboratory wave flume (Chatou, France). We measure the wave damping with 13 resistive waves gauges along a distance L = 22.5 m for the “low” density and L = 12.15 m for the “high” density of vegetation mimics. A JONSWAP spectrum is used for the generation of irregular waves with significant wave height Hs ranging from 0.10 to 0.23 m and peak period Tp ranging from 1 to 3 s. Artificial vegetation is a model of Posidonia oceanica seagrass species represented by slightly flexible polypropylene shoots with 8 artificial leaves of 0.28 and 0.16 m height. Different hydrodynamics conditions (Hs, Tp, water depth hw) and geometrical parameters (submergence ratio α, shoot density N) have been tested to see their influence on wave attenuation. For a high submergence ratio (typically 0.7), the wave attenuation can reach 67% of the incident wave height whereas for a low submergence ratio (< 0.2) the wave attenuation is negligible. From each experiment, a bulk drag coefficient has been extracted following the energy dissipation model for irregular non-breaking waves developed by Mendez and Losada (2004). This model, based on the assumption that the energy loss over the species meadow is essentially due to the drag force, takes into account both wave and vegetation parameter. Finally, we found an empirical relationship for Cd depending on 2 dimensionless parameters: the Reynolds and Keulegan-Carpenter numbers. These relationships are compared with other similar studies.

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