船舶结构力学中的“伪安定”问题

从理论和试验研究两个方面论述了船舶结构力学中的“伪安定”问题．提出了一个判别结构是否发生伪安定状态的能量准则，并将这个准则具体应用于反复波浪砰击载荷作用下以及反复质量撞击作用下船舶板的伪安定分析．给出了分析实例及试验结果．分析表明：对于承受反复动载作用、边界受到约束的船舶板，当外载荷所作的总功小于板构件所能贮存的最大弹性变形能时，该结构将是伪安定的．集中质量反复撞击固支铝合金圆板的试验结果证实了理论的预报．

Pseudo Shakedown in Structural Mechanics of Ships

The pseudo shakedown phenomenon in the structural mechanics of ships is investigated both theoretically and experimentally. An energy criterion, which can be used to judge the pseudo shakedown state of structure is postulated. The energy criterion is applied to the analysis of pseudo shakedown of ship plates under either repeated wave slamming or repeated mass impacts. An illustrative example and some experimental results are given. According to the analysis, it is found that, for the axially restrained ship plate with repeated dynamic loads, the elastic strain energy absorbed in the structure increases with that of the plastic deformation of the structure, the structure will be in a pseudo shakedown state when the maximal elastic strain energy to be absorbed in the deformed structure equals to the external work of the dynamic load in magnitude. The postulation is confirmed by the results of repeated mass impact on a fully clamped circular plate.