scholarly journals ANALISIS NUMERIK PENGARUH KECEPATAN TERHADAP SEAKEEPING KAPAL PATROLI PADA DAERAH PELAYARAN SEASTATE 7

2021 ◽  
Vol 4 ◽  
pp. 13-17
Author(s):  
Mohammad Taufik Ar Rozi ◽  
Betty Ariani ◽  
Dedy Wahyudi
Keyword(s):  
Water Surface ◽  
Degrees Of Freedom ◽  
Body Shape ◽  
Critical Value ◽  
Vertical Movement ◽  
Sea Waves ◽  
Six Degrees Of Freedom ◽  
A Value ◽  
Wave Angle ◽  
Standard Limit

Patrol boat is designed not to be slow in its movement on the water surface. To be able to move quickly and agilely, the most important requirement for this type of ship is in its maneuverability. The ship's motion at sea (seakeeping) is influenced by several things, speed, body shape, and the direction of the ship's heading waves. In this study, we analyze the six degrees of freedom, especially on the response of the ship's vertical movement, namely rolling on the sea waves of Seastate 7, especially in extreme weather in the South China Sea. The standard limit used is NORDFORSK 1987 with Light Manual Work Criteria. By entering parameters such as variations in speed and wave angle, such as 0°, 45°, 180° and 270°, then from the graph it can be seen the critical value for each movement. The calculation is carried out with the help of computational software Maxsurf Motions Advanced 20 V8i. The results of this study are the maximum roll movement value that occurs at a speed of 14 knots with a wave angle of 45° with a roll angle value of 6.40o. Furthermore, there is a decrease in the value of the movement along with the increase in the speed of the ship. The minimum roll value occurs when the wave angle is 270° when the ship's speed is 28 knots with a value of 5.69o.

Analysis of the Motion of Shipboard Missiles under the Excitation of Sea Waves

2013 ◽  
Vol 816-817 ◽  
pp. 825-830
Author(s):  
Yun Long Wang ◽  
Wei Min Lv ◽  
Jia Chen Feng ◽  
Yong Chuan Jin
Keyword(s):  
Environmental Analysis ◽  
Frequency Response Function ◽  
Degrees Of Freedom ◽  
Ship Motion ◽  
Irregular Waves ◽  
Motion Model ◽  
Sea Waves ◽  
Regular Waves ◽  
Six Degrees Of Freedom ◽  
Amplitude Frequency Response

Waves in different sea conditions are simulated by the Bretscheider double parameters spectrum using randomly chosen discrete frequencies as its parameters. Ship motion model of six degrees of freedom is established under the Ship coordinates system. As the ship system is linear, the ship motion under irregular waves can be calculated through the amplitude-frequency response function obtained by solving the model when the input is the superposition of regular waves. Finally according to the coordinate transformation between the ship coordinates system and the missile coordinates system, the motion of the shipboard missiles under excitation of sea waves can be analyzed to support the environmental analysis of its combat duty process.

scholarly journals ANALYSIS OF THE RESPONSE OF OFFSHORE-MOORED SHIPS TO WAVES

1964 ◽  
Vol 1 (9) ◽  
pp. 46
Author(s):  
Jan L. Leendertse
Keyword(s):  
Degrees Of Freedom ◽  
Vertical Plane ◽  
Longitudinal Axis ◽  
Mooring Line ◽  
Wave System ◽  
Sea Waves ◽  
Mooring Lines ◽  
Six Degrees Of Freedom ◽  
General Terms ◽  
Relationship Of

A vessel moored at sea will experience complicated series of translational and rotational oscillations due to sea waves. These motions can be considered as the summation of six components, three translational and three rotational. In the presently available analyses of motions of unmoored ships, differential equations can be written for each mode of movement. Unfortunately, motions in one of these modes are coupled to motions of other modes, and the analysis becomes rather complicated. Generally, the problem is simplified by neglecting some of the coupling effects and by specifying the position of the vessel in the wave system. This study develops and analyzes a model for a moored ship restrained by mooring lines, using the presently available mathematical models for the free ship and the force-displacement relationship of the cable-holding points on the ship. The coupled movement (three degrees of freedom) in a vertical plane through the longitudinal axis of the vessel and the generated mooring-line forces are considered in detail. The general case of six degrees of freedom in arbitrary heading is discussed briefly in general terms.

Control of processing at multi-tool two-support setup

2020 ◽  
pp. 67-73
Author(s):  
N.D. YUsubov ◽  
G.M. Abbasova
Keyword(s):  
Degrees Of Freedom ◽  
Factor Model ◽  
Angular Displacement ◽  
Factor Models ◽  
Technological System ◽  
Displacement Control ◽  
Model Accuracy ◽  
Six Degrees Of Freedom ◽  
Angular Displacements ◽  
And Control

The accuracy of two-tool machining on automatic lathes is analyzed. Full-factor models of distortions and scattering fields of the performed dimensions, taking into account the flexibility of the technological system on six degrees of freedom, i. e. angular displacements in the technological system, were used in the research. Possibilities of design and control of two-tool adjustment are considered. Keywords turning processing, cutting mode, two-tool setup, full-factor model, accuracy, angular displacement, control, calculation [email protected]

scholarly journals Design and Calibration of a Hall Effect System for Measurement of Six-Degree-of-Freedom Motion within a Stacked Column

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3740
Author(s):  
Olafur Oddbjornsson ◽  
Panos Kloukinas ◽  
Tansu Gokce ◽  
Kate Bourne ◽  
Tony Horseman ◽  
...  
Keyword(s):  
Hall Effect ◽  
Degrees Of Freedom ◽  
Reactor Core ◽  
Degree Of Freedom ◽  
Life Extension ◽  
Scale Model ◽  
Design Development ◽  
Seismic Safety ◽  
Six Degrees Of Freedom ◽  
Six Degree Of Freedom

This paper presents the design, development and evaluation of a unique non-contact instrumentation system that can accurately measure the interface displacement between two rigid components in six degrees of freedom. The system was developed to allow measurement of the relative displacements between interfaces within a stacked column of brick-like components, with an accuracy of 0.05 mm and 0.1 degrees. The columns comprised up to 14 components, with each component being a scale model of a graphite brick within an Advanced Gas-cooled Reactor core. A set of 585 of these columns makes up the Multi Layer Array, which was designed to investigate the response of the reactor core to seismic inputs, with excitation levels up to 1 g from 0 to 100 Hz. The nature of the application required a compact and robust design capable of accurately recording fully coupled motion in all six degrees of freedom during dynamic testing. The novel design implemented 12 Hall effect sensors with a calibration procedure based on system identification techniques. The measurement uncertainty was ±0.050 mm for displacement and ±0.052 degrees for rotation, and the system can tolerate loss of data from two sensors with the uncertainly increasing to only 0.061 mm in translation and 0.088 degrees in rotation. The system has been deployed in a research programme that has enabled EDF to present seismic safety cases to the Office for Nuclear Regulation, resulting in life extension approvals for several reactors. The measurement system developed could be readily applied to other situations where the imposed level of stress at the interface causes negligible material strain, and accurate non-contact six-degree-of-freedom interface measurement is required.

scholarly journals Designing of Drive Systems in the Aspect of the Desired Spectrum of Operation

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2562
Author(s):  
Tomasz Dzitkowski ◽  
Andrzej Dymarek ◽  
Jerzy Margielewicz ◽  
Damian Gąska ◽  
Lukasz Orzech ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Dynamic Parameters ◽  
Synthesis Algorithm ◽  
Moments Of Inertia ◽  
Driving System ◽  
Six Degrees Of Freedom ◽  
Resonance Frequencies ◽  
Drive Systems ◽  
Power Component

A method for selecting dynamic parameters and structures of drive systems using the synthesis algorithm is presented. The dynamic parameters of the system with six degrees of freedom, consisting of a power component (motor) and a two-speed gearbox, were determined, based on a formalized methodology. The required gearbox is to work in specific resonance zones, i.e., meet the required dynamic properties such as the required resonance frequencies. In the result of the tests, a series of parameters of the drive system, defining the required dynamic properties such as the resonance and anti-resonance frequencies were recorded. Mass moments of inertia of the wheels and elastic components, contained in the required structure of the driving system, were determined for the selected parameters obtained during the synthesis.

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