Critical Assessment of Containership Motions in Time Domain

Abstract

This study investigates the time-domain motion response of a containership to wave excitation using the Boundary Element Method (BEM). Accurate prediction of ship motions is crucial for safe and efficient maritime operations. This research focuses on a comprehensive analysis of the vessel's six degrees of freedom (surge, sway, heave, roll, pitch, and yaw) to understand its dynamic behavior in realistic sea conditions. A 3D model of the containership hull, derived from a SolidWorks-generated STL file with a surface area of 12,569,830,985.5274 mm² and overall dimensions of 213078.4316 mm (X), 36049.9816 mm (Y), and 16344.666 mm (Z), serves as the geometric basis for the BEM calculations. The time-domain BEM approach allows for a detailed examination of the vessel's transient and steady-state responses to wave forces. The analysis encompasses the computation of wave-induced forces, added mass, and damping coefficients, which are then incorporated into the vessel's equations of motion. The study presents time histories of displacement, velocity, and acceleration for each motion mode. Key findings reveal significant motion amplitudes in surge, sway, and heave, with peak displacements reaching approximately 0.5m, 0.1m, and 0.5m, respectively. Rotational motions, while smaller in displacement, exhibit significant velocities and accelerations, particularly in pitch and yaw. Specifically, yaw velocity and acceleration reach substantial values of approximately 2000 rad/s and ±2000 rad/s², respectively, highlighting the critical role of stabilization systems. The results emphasize the importance of considering all six degrees of freedom in ship motion analysis. The identified critical motion modes and their associated peak values provide crucial information for optimizing ship design, enhancing stability, and ensuring safe operation in challenging sea environments. This study demonstrates the effectiveness of the time-domain BEM in capturing the complex hydrodynamic interactions and providing valuable data for improving vessel performance and safety.