Pseudo-shakedown in the collision mechanics of ships

The pseudo-shakedown phenomenon in the collision mechanics of ships is inve stigated both theoretically and experimentally. An energy criterion, which can be used to judge the pseudo-shakedow state of structures is postulated. The energy criterion is applied to the analysis of pseudo-shakedown of shi p plates under repeated mass impacts. An illustrative example and experimen tal results are given. According to the analysis, it is found that, for the axially restrained ship plate with repeated dynamic loads, the elastic str ain energy absorbed in the structure increases with that of the plastic def ormation of the structure. The structure will reach a pseudo-shakedown stat e when the maximal elastic strain energy to be absorbed in the deformed str ucture is equal to or larger than the external work of the dynamic load in magnitude. This postulation has been confirmed by the experimental results of repeated mass impact on a fully clamped plate, (C) 2000 Published by Els evier Science Ltd. All rights reserved.