Session: 02-10-01 Collision and Crashworthiness 1

Paper Number: 80209

80209 - Rapid Assessment of Ship Bottom Grounding Damage Considering Combined Surge and Heave Motion 

Abstract — In most of the available literature in ship grounding analysis, the ship is supposed to run aground over a rock with only a surge velocity. However, in situations where the vessel is navigating in presence of waves, observation of real grounding events [1] and recent numerical studies [2] showed that considering both heave and surge initial velocities may lead to multiples breaches in the bottom plating, resulting in an overall damage extent up to 4 times the one obtained by assuming only a surge velocity.

Despite the increase in computing capacity of computers, the nonlinear finite element method remains very time consuming, which prevents its use for probabilistic damage stability analysis. In the present paper, a simplified analytical approach based on plastic analysis is developed, with the aim to rapidly assess the damage of a ship bottom plating running aground over a rock. This latter is idealised as an elliptic paraboloid and the ship is assumed to run aground with both heave and surge velocities. Sliding and raking situations are considered and the criteria used to switch from one mode to the other is discussed. The model is then confronted to finite element simulations for different rock shapes, velocities, and friction coefficients. Although the comparison shows that the proposed approach gives a good prediction of the dissipated energy in most cases, some limitations are also highlighted.

Keywords: Ship grounding, simplified method, plastic limit analysis, multiple breaches

 

References

[1]         Zaraphonitis et al. 2015. Evaluation of risk from raking damages due to grounding, Final report, EMSA/OP/10/2013, Report No. 2015-0168m Rev, 2. Available from www.emsa.europa.eu.

[2]         Le Sourne H, Pineau J., Umunnakwe CB, Wesoly T, Dorival O. On the influence of buoyancy forces , failure strain and friction coefficient on the damage extent of a grounded ship. Mar. Struct. - MARSTRUCT, 2021.

 

 

Presenting Author: Jean-Philippe Pineau ICAM

Authors:

Jean-Philippe Pineau ICAM
Hervé Le Sourne ICAM