Experimental Study on the Strength of Collision Barriers in Nuclear Ships

Abstract

The purpose of this study is to examine the ultimate strength of resisting type collision barriers which are installed in nuclear ships. Two kinds of ship side structures containing such barriers were designed by way of experiment as examples. The characteristic of one is that it consists of a grillage of horizontal and vertical webs, and the other's is that more deck plates are set than usual. Four series tests were carried out on these structures as follows, (1) one deck element model tests against a rigid bow model, (2) structural model tests against a rigid bow model, (3) double-hull element model tests against a rigid bow model, (4) structural model tests against two actual bow models.From the analysis of the test results, the collapse modes were classified into two patterns such as crushing collapse of only the loaded region and bending collapse of the whole structure. The strength in the former collapse could be attributed to the ultimate strength of the members which were carrying a load directly beneath it, where an effective sectional area, which was calculated by the effective width formula, was taken into account. The latter could be explained considering a limit load obtained by the plastic hinge method, where an effective full plastic moment, which was calculated with a sectional area excepting the ineffective parts due to buckling, was taken into account.Finally, a way to estimate ultimate strength was derived for the above-mentioned two kinds of ship side structures.