Investigating the effect of brittle crack propagation on the strength of ship structures by using peridynamics

Ship structures can experience damages although they are initially designed with high safety factors. These damages can be caused by many reasons such as collisions, groundings, explosions, corrosion, fatigue, overloading or extreme conditions. Brittle damages can occur on the ship structures in some special conditions such as low-temperature, high-loading rate, multi-axial stress constraint, or low weldability of steel. In this study, progressive brittle damages on a ship structure subjected to different loading conditions are predicted. A novel peridynamic method based on a recently developed peridynamic shell model is presented to evaluate the structural strength during the damage evolution process for the first time in the literature. First, longitudinal strength (bending moment) of a ship structure is numerically calculated during damage propagations. The maximum longitudinal strength of the intact ship is verified with the experimental result. Next, the simulations are further extended to investigate the ship structure with initial damage, i.e. rectangular cut-out at the bottom. The longitudinal strength for an intact ship and a ship with different sizes of cut-outs are also compared. Finally, torsional strength during the damage propagation process for a ship structure with a cut-out is also presented.