PREDICTION OF THE DAMAGE EXTENTS OF SHIP'S DOUBLE HULL SIDE STRUCTURES SUBJECTED TO LATERAL COLLISIONS

摘要

Lateral collision tests were conducted on two steel double-hull side structure models, models DH-3 and DH-4. The models were approximately one-seventh scale of a VLCC (Very Large Crude Carrier), and the small longitudinal stiffeners of a VLCC were smeared into the shell plates. The collision tests were performed using a car crash testing facility. The striker had a knife-edge type header and its mass was 1,350 kg. The collision velocities were 7.224 m/s and 10.0 m/s for models DH-3 and DH-4, respectively. The collision test results are briefly reported in this paper. Using a commercial FEA package, numerical collision analyses were then conducted for the two new models together with another two models of one-tenth scale, which were reported elsewhere. In the numerical analyses the strain and strain-rate hardenings were considered. The convergence test was also performed to obtain an optimal mesh size. The numerical predicted damage extents were compared with those of the experiments. The prediction errors were in the range of - 5.7 % to + 6.8 %. An analytical approach was also attempted to predict the damage extents of double-hull structures subjected to lateral collisions. Compared with the experimental and numerical predictions the analytical predictions provide acceptable accuracies for the initial design stage. For a more rational ship structural design against collision, future studies are proposed to improve the prediction accuracy and reliability.