Fast Strength Assessment of Mitre Gates to Ship Impact

Fast Strength Assessment of Mitre Gates to Ship Impac

Extension of the super-elements method to the analysis of oblique collision between two ships

The present article is concerned with the resistance of a ship during a collision with another ship. The paper is directly related to the so called super-elements method developed to estimate the capability of a ship to withstand to an impact. This approach consists of dividing the structure into several elements (the so-called super-elements), whose resistance to collision is evaluated individually. At the recent stage of development, the super-elements method is only able to treat the case of perpendicular collision scenarios. The purpose of this paper is to go one step further, by establishing analytical formulations giving the resistance of various super-elements to an oblique impact.As a first step, the paper gives a short description of the original super-elements method. After that, analytical calculations in oblique collision cases are performed for the different super-elements involved in the procedure. Finally, the formulations are validated by comparison with results provided by classical nonlinear finite element method. As a conclusion, some perspectives on the future work are presented

On the applicability of Taylor’s theory to the underwater blast response of composite plates

International audienceThe response of a plane, air-backed plate attached to a rigid baffle when subjected to an underwater plane shock wave is investigated numerically and analytically. The numerical simulation takes into account a full threedimensional fluid model involving water cavitation effects. Different numerical models are employed and validated by comparing against various experimental results from the literature. The validated numerical setup is then used to simulate the underwater shock response of simply-supported, air-backed, carbon-fiber/epoxy rectangular plates attached to a rigid baffle. Simplified analytical solution is developed based on two-step approach. The two stages considered are early-time phase that adapts Taylor’s fluid-structure theory to calculate an impulsive velocity for the plate and long-time phase that involves determining its free oscillation response withinlinear elastic domain, taking into account the water-added mass effect. Finally, the applicability of the proposed method is investigated by performing different numerical simulations regarding various combinations of peak pressures and decay times, change of aspect ratios, change of materials as well as ply orientations

Numerical simulation of the dynamic behaviour of resilient mounts for marine diesel engines

On board ships, to avoid high levels of structure-borne noise due to marine four strokes diesel engines, the latter are usually resiliently mounted. In order to improve the effectiveness of the decoupling between the diesel engines and the ship structures, it is important to have available tools and numerical models that simulate the dynamic behaviour of the isolator system as well as of the receiving structures. In the paper, after an introduction to the basics for the characterization of passive resilient mounts in high frequency range, an FE non-linear dynamic model of the isolator is presented. Such model takes into account the dynamics of the cast-iron parts, the contact between the top and base casting with the rubber core and the non-linear behaviour of the constitutive law of rubber. A procedure to achieve the characteristics parameters of rubbers is presented. The simulations have been then validated by experimental tests

A review of technical solutions and simulations approaches for ship collisions with lock gates

peer reviewedDevelopment of Analytical method sto assess the ship impact on lock gate