Piston Mode and Sloshing Resonances in a Damaged Ship

2010 ◽  
Author(s):  
X. J. Kong ◽  
O. M. Faltinsen
Keyword(s):  
Theoretical Analysis ◽  
Hydrodynamic Coefficients ◽  
Response Functions ◽  
Sea Waves ◽  
Structural Failure ◽  
Unified Approach ◽  
Hydrodynamic Problem ◽  
Physical Problems ◽  
Piston Mode ◽  
Damaged Ship

This work investigates the motions of a damaged ship in regular beam sea waves. The ship geometry including the damaged compartment (with opening) is modeled by using a unified approach called Hull Reshaped Method [1] and the hydrodynamic problem is solved by applying a 3D potential flow code. Linear hydrodynamic coefficients and excitation loads together with experimental nonlinear viscous roll damping are used in the calculations of the motion response functions. In addition to the natural roll resonance, the piston mode and sloshing resonances are numerically observed. By applying simplified theoretical analysis, these two resonances are further confirmed for a damaged ship with opening in the hull defined by the SOLAS rule [2]. The resulting physical problems, for instance, dry bottom, roof impact and possible structural failure in the damaged compartment are predicted from the simulations.

Nonlinear Camera Response Functions and Image Deblurring: Theoretical Analysis and Practice

2013 ◽  
Vol 35 (10) ◽  
pp. 2498-2512 ◽  
Author(s):  
Yu-Wing Tai ◽  
Xiaogang Chen ◽  
Sunyeong Kim ◽  
Seon Joo Kim ◽  
Feng Li ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Image Deblurring ◽  
Response Functions

Analytical Prediction of Progressive Structural Failure of a Damaged Ship for Rapid Response Damage Assessment

2014 ◽  
Author(s):  
Alexander Bardetsky ◽  
AiKuo Lee
Keyword(s):  
Decision Making ◽  
Crack Propagation ◽  
Residual Strength ◽  
Damage Assessment ◽  
Rapid Response ◽  
Analytical Prediction ◽  
Fe Modeling ◽  
Structural Failure ◽  
Sea Wave ◽  
Damaged Ship

The assessment of the residual strength of a damaged ship is a key element of ABS’ Rapid Response Damage Assessment (RRDA) program. When determining the residual strength, it is important to understand how the initial structural damage can spread in response to sea wave dynamic loads and can lead to a gradual reduction of the ship’s residual strength. This progressive, time-dependent structural failure caused by cracks emanating from the damaged area could eventually lead to total hull girder collapse. This is why it is important to quantify the progressive structural failure over time when assessing the residual strength of the damaged ship. Until now, progressive structural failure analysis has been conducted numerically using the Finite Element (FE) modeling approach. While this approach is accurate, it is extremely time-consuming, which makes it inappropriate for incident response, where time for decision-making is very limited. In order to overcome this limitation, an alternative analytical modeling approach for assessing the progressive structural failure of a damaged ship is proposed. This paper presents a new comprehensive procedure for analytical prediction of crack propagation under sea wave loading using spectral fatigue analysis, beam theory, fracture mechanics and an equivalent stress intensity factor (SIF) range concept. The SIF range obtained analytically is validated by FE modeling of a damaged ship subjected to sea wave dynamic loading. The procedure for analytical prediction of the crack propagation is demonstrated for a typical, modern 170,000 DWT bulk carrier in a full load condition. The results of this research can be used to support informed decision-making when analyzing a vessel’s residual strength for the transit voyage from the accident location to a repair facility.

A Theoretical Analysis of Transient Sound Radiation From a Clamped Circular Plate

1984 ◽  
Vol 51 (1) ◽  
pp. 41-47 ◽  
Author(s):  
A. Akay ◽  
M. Tokunaga ◽  
M. Latcha
Keyword(s):  
Theoretical Analysis ◽  
Circular Plate ◽  
Impulse Response ◽  
Sound Radiation ◽  
Free Vibrations ◽  
Mode Shapes ◽  
Impulse Response Functions ◽  
Response Functions ◽  
Surface Integral ◽  
Pressure Impulse

A theoretical analysis of transient sound radiation from a clamped circular plate is given using a pressure impulse response method. The vibration response of the plate to a transient point force is obtained. The modal pressure impulse response functions for the plate are derived from the Rayleigh surface integral and numerically convoluted with the modal acceleration response of the plate. The impulse response functions are closely related to the mode shapes and the geometry of the problem. They relate the spatial domain to the temporal domain of the pressure waves. The pressure impulse response waveforms are given for a number of plate modes and the changes in the waveforms with distance from the plate are shown. Sound radiation due to forced and free vibrations of the plate are discussed.

scholarly journals Neuro-current response functions: A unified approach to MEG source analysis under the continuous stimuli paradigm

NeuroImage ◽  
2020 ◽  
Vol 211 ◽  
pp. 116528 ◽  
Author(s):  
Proloy Das ◽  
Christian Brodbeck ◽  
Jonathan Z. Simon ◽  
Behtash Babadi
Keyword(s):  
Source Analysis ◽  
Current Response ◽  
Response Functions ◽  
Unified Approach

A Small Scale Field Experiment for Hydrodynamic Coefficients of Morison’s Forces in Random Waves

2013 ◽  
Author(s):  
Felice Arena ◽  
Vincenzo Fiamma
Keyword(s):  
Field Experiments ◽  
Wave Spectrum ◽  
Wave Force ◽  
Small Scale ◽  
Random Wave ◽  
Wave Forces ◽  
Hydrodynamic Coefficients ◽  
Sea Waves ◽  
Ocean Engineering ◽  
Scale Field

The paper deals with wave forces on vertical and horizontal cylinders through the Morison’s equation. In particular, the hydrodynamics coefficients on cylinders are investigated by means of two small scale field experiments in the Natural Ocean Engineering Laboratory (NOEL) of the Mediterranea University of Reggio Calabria, by analyzing two stationary random processes of time: the measured wave force Fa(t), and the wave force calculated with the Morison equation Fc(t). The kinematics in the Morison’s equation is obtained with the theory of wind-generated waves from the directional wave spectrum obtained from measurements of surface waves. Starting from the measurements a new approach is proposed for the evaluation of the hydrodynamic coefficients of Morison’s forces for random sea waves. Finally, the distributions of the peaks of the random wave forces, Fa(t), and Fc(t), is achieved.

Equilibrium magnetohydrodynamic flows of liquid metals in magnetorotational instability experiments

2010 ◽  
Vol 644 ◽  
pp. 257-280 ◽  
Author(s):  
I. V. KHALZOV ◽  
A. I. SMOLYAKOV ◽  
V. I. ILGISONIS
Keyword(s):  
Liquid Metal ◽  
Theoretical Analysis ◽  
Liquid Metals ◽  
Annular Channel ◽  
Reynolds Numbers ◽  
Unified Approach ◽  
Magnetorotational Instability ◽  
Annular Channels ◽  
Magnetohydrodynamic Flows ◽  
Different Types

A theoretical analysis of equilibrium magnetohydrodynamic flows in annular channels is performed from the perspective of establishing required conditions for liquid metal magnetorotational instability (MRI) experiments. Two different types of fluid rotation are considered: electrically driven flow in an annular channel and Taylor–Couette flow between rotating cylinders. The structure of these flows is studied within a unified approach as a function of the Hartmann and Reynolds numbers. The parameters appropriate for realization of MRI experiments are determined.

scholarly journals Experimental studies of a damaged ship section in beam sea waves

2020 ◽  
Vol 97 ◽  
pp. 102090 ◽  
Author(s):  
M.A. Siddiqui ◽  
M. Greco ◽  
C. Lugni ◽  
O.M. Faltinsen
Keyword(s):  
Experimental Studies ◽  
Sea Waves ◽  
Damaged Ship
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