Structural response analysis of slamming impact on free fall lifeboats

Ringsberg, Jonas W.; Heggelund, Svein Erling; Lara, Paul; Jang, Beom-Seon; Hirdaris, Spyros

doi:10.1016/j.marstruc.2017.03.004

Cited by 19 publications

(6 citation statements)

References 8 publications

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“…The pressure becomes zero whenever the relative motion of the deck is negative. Figure 8 presents the pressure distribution along the wedge of the hull plotted by using the pressure formula given in equation (14). Here, the slamming pressure is denoted by p slam and has been non-dimensionalised by the factor 1=0:5r u rel À Á 2 .…”

Section: Resultsmentioning

confidence: 99%

A semi analytic method for the analysis of the symmetric hydroelastic response of a container ship under slamming and green water loads

Sengupta

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Hirdaris

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part M:

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This paper presents a semi analytic time domain method for the analysis of the symmetric hydroelastic response of a container ship subject to slamming and green water loads. An Impulse Response Function (IRF) is adopted for the calculation of radiation, diffraction and wave excitation forces. Local hydrodynamic forces associated with green water on decks and slamming loads are respectively modelled by the Buchner’s Dam Break Model and a Generalised Wagner Model. The structural responses are captured by Euler-Bernoulli beam theory and solved by the modal superposition method. The Duhamel Integral technique is used to evaluate the dynamic response. A parametric study demonstrates how external forces may affect the global wave induced vertical bending moments and shear forces. Numerical simulations are compared against a hybrid method that combines computational fluid dynamics, boundary element and finite element methods for low to medium frequency induced dynamic response. It is concluded that the proposed semi analytic methodology is fast and accurate and may be useful at concept ship design stage.

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Section: Resultsmentioning

confidence: 99%

A semi analytic method for the analysis of the symmetric hydroelastic response of a container ship under slamming and green water loads

Sengupta

Show

Hirdaris

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part M:

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“…In addition to the model experiment, some scholars used a computational method to analyze the freefall of the boat, which was mainly divided into two aspects. First, computational fluid dynamics (CFD) technology was used to numerically simulate the water entry of the lifeboat, and the slamming load of the hull was analyzed by the simulated results [10][11][12]. The second method was to establish a mathematical model for the freefall of the lifeboat for predicting the lifeboat motion attitude, and analyzing the risk of injury to the crew [13][14][15].…”

Section: Related Workmentioning

confidence: 99%

Computational Model for Simulation of Lifeboat Free-Fall during Its Launching from Ship in Rough Seas

Qiu

Ren

2020

JMSE

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In order to improve the accuracy of the freefall of lifeboat motion simulation in a ship life-saving simulation training system, a mathematical model using the strip theory and Kane’s method is established for the freefall of the lifeboat into the water from a ship. With the boat moving on a skid, the model of the ship’s maneuvering mathematical group (MMG) is used to model the motion of the ship in the waves. Based on the formula of elasticity and friction theory, the forces of the skid acting on the boat are calculated. When the boat enters the water, according to the analytical solution theory of slamming, the slamming force of water entry is solved. The simulation experiments are carried out by the established model. The results of the numerical simulation are compared with the calculation results of the hydrodynamics software Star CCM+ at water entry under initial condition A in the paper. The position and velocity of the center of gravity of the boat, the angle, and velocity and acceleration of pitch calculated by the two methods are in good agreement. There is a little difference between the values of translation acceleration calculated by the two methods, which is acceptable. This shows that our numerical algorithm has good accuracy. A qualitative analysis is performed to find the safe point of water entry under the condition of different wave heights and two situations of a ship encountering waves. Finally, the model is applied to the ship life-saving training system. The model can meet the system requirements and improve the accuracy of the simulation.

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“…The impact of a solid object on a free surface is of importance in ocean engineering, with examples including ship slamming (Abrate 2011; Kapsenberg 2011), air-to-sea missiles (May 1975), free-fall lifeboats (Ringsberg et al. 2017) and surface-piercing propellers (Yari & Ghassemi 2016). The impact of a solid body on water is also observed in nature.…”

Section: Introductionmentioning

confidence: 99%