Collision tests with rigid and deformable bulbous bows driven against double hull side structures

Evaluation of ship collision safety is commonly carried out with a striking ship assumed to be rigid. This approach is in line with classic safety assessments taking a worst case scenario into account. It is in addition to that justified because the majority of ship-ship collisions occur without significant damage at the striking vessel. Nevertheless considering stiffness of the striking vessel might have noticeable influence on absorbable collision energies. Safety level could be increased significantly when design of bulbous bows is carried out also under the aspect of good crushing behaviour regarding collision load. However up to now experimental verification of this context is missing. This paper reports about collision experiments with rigid and deformable bulbous bows driven against double hull side structures that have been carried out on the test facility of the Institute for Ship Structural Design and Analysis of TUHH. Actual validation status of numerical calculations is presented based on test results also with regard to material behaviour.