Estimating the safety of STS transfer operations with fuzzy FTA

Abstract

In this paper a specific procedure for the structural assessment of a container stack is implemented to a realistic case in order to evaluate its effectiveness in the prediction of the operational limits of a container vessel. The feasibility of an extensive calculation based on such procedure is tested, paving the way to the direct analysis of a container stack subject to the inertial loads arising from the ship motions. The procedure is based on a 3D non-linear FE analysis coupled with a direct simulation of non-linear ship motions for the determination of inertial forces acting on a container stack. A non-linear approach has been used for modelling both the ship motion response and the container stack structural response, leading to a global large amplitude analysis. A simplified model of a container stack has been defined in order to decrease the computational cost of the structural calculations, allowing for a use in the framework of an extensive analysis considering many different ship sailing conditions. As final results, diagrams showing the occurrence of failure of container structures or lashing equipment are presented

Influence of ship dynamics modelling on the prediction of fishing vessels roll response in beam and longitudinal waves

“…The 6-DOF model used herein is SHIXDOF (Bulian and Francescutto, 2013;Bulian et al, 2012Bulian et al, , 2015Bulian et al, , 2016Cercos-Pita et al, 2016;Moro et al, 2015). SHIXDOF integrates the 6-DOF nonlinear rigid body equations of motions, projected, as usual, to the ship-fixed reference system, under the effect of "external" forces:…”

“…This paper focuses on fishing vessels and addresses parametric roll 2:1 subharmonic resonance in longitudinal regular waves and 1:1 roll resonance in beam regular sea waves, at zero speed, considering a wide range of wave conditions. Results from a high fidelity 6-DOF blended model (Bulian and Francescutto, 2013;Bulian et al, 2012Bulian et al, , 2015Bulian et al, , 2016Cercos-Pita et al, 2016;Moro et al, 2015), which has the main characteristics for application at the envisioned Direct Stability Assessment Level of IMO Second Generation Intact Stability Criteria (SLF 52/WP.1-Annex 2, 2010; Annex 1 in SDC 4/WP.4, 2017), are compared with outcomes from simpler 1-DOF nonlinear roll models for the two considered conditions (Bulian, 2006;Bulian and Francescutto, 2006;Bulian et al, 2012). Predictions based on simplified approximate prediction formulae derived from the proposed 1-DOF roll models are also considered.…”