A combined numerical and semi-analytical collision damage assessment procedure

Ship collisions are increasingly simulated with numerical methods predicting the structural damage, respectively the ships' safety, in such accidental event. The latest analyses techniques can take the non-linear structural behaviour and the motions of the colliding vessels into account, however using time-consuming numerical models. Hence, a single dynamic collision can be analysed with a fair degree of accuracy, but at high computational cost. Therefore, this article presents a combined numerical and analytical procedure to assess ship collision damage with significantly lower computational cost. Numerical quasi-static collision simulations estimate the non-linear structural behaviour for a given vessel colliding at selected vertical locations. This provides the force versus penetration curves, which thus depends on the structural arrangement at the striking location. Hence, the semi-analytical collision analysis is calibrated based on these structural resistance curves in order to estimate the change in available energy for structural deformation considering different longitudinal striking locations and angles. As a result, the collision damage, respectively penetration depth and length, can be estimated for vessels of different dimensions and mass ratio's subjected to various collision situations if the presented procedure is applied.