基于失效模式的船体典型加筋板极限承载能力预报

目的 探究失效模式对加筋板极限承载能力的影响,并提出加筋板极限承载能力预报方法。方法 利用非线性有限元法,对某典型船体加筋板模型进行分析。考虑加筋柔度与甲板柔度2种主要影响因素,分析加筋板的破坏机理,明确不同失效模式下甲板柔度与加筋柔度对加筋板极限承载能力的影响规律,并提出不同失效模式下加筋板极限承载能力的经验公式。结果 甲板柔度一定时,随着加筋柔度的增加,加筋板的破坏模式由板与加筋的局部屈曲,变为板格的局部屈曲,最后演变为加筋板的整体梁柱屈曲。板格宽度较低时,随着加筋高度的增加,加筋板的破坏模式会由梁柱屈曲变为板格屈曲;板格宽度较大时,不同加筋高度的加筋板破坏模式均为板格屈曲。不同失效模式下,加筋板的载荷位移曲线也呈现出不同的趋势。结论 加筋柔度与甲板柔度二者之间的数量关系会导致加筋板呈现出不同的失效模式,此时二者对加筋板极限承载能力的影响规律会有所不同。此外,在设计阶段,需保证加筋与甲板的刚度匹配,避免出现材料利用率过低的现象。

Prediction of Ultimate Bearing Capacity of Typical Stiffened Plates Based on Failure Modes

The work aims to explore the effect of failure modes on the ultimate bearing capacity of stiffened plates, and to propose a method for predicting the ultimate bearing capacity of stiffened plates. The nonlinear finite element method was used to analyze the model of a typical hull stiffened plate. Considering the two main affecting factors of reinforcement flexibility and deck flexibility, the failure mechanism of the stiffened plate was analyzed. The effect rules of the deck flexibility and reinforcement flexibility on the ultimate bearing capacity of the stiffened plate under different failure modes were clarified. And an empirical formula for ultimate bearing capacity of the stiffened plate in different failure modes were proposed. The result showed that when the flexibility of the deck was constant, with the increase of the reinforcement flexibility, the failure mode of the stiffened plate changed from the local buckling of the plate and the reinforcement to the local buckling of the panel, and finally to the overall beam-column buckling of the stiffened plate. When the panel width was low, the failure mode of the stiffened plate changed from beam-column buckling to panel buckling with the increase of the reinforcement height; and when the panel width was large, the failure mode of the stiffened plates with different reinforcement heights was panel buckling. At the same time, under different failure modes, the load-displacement curves of the stiffened plates also showed different trends. In conclusion, the quantitative relationship between the reinforcement flexibility and the deck flexibility will lead to different failure modes of the stiffened plate. At this time, the effect of the two on the ultimate bearing capacity of the stiffened plate will be different. In the design stage, it is necessary to ensure that the stiffness of the reinforcement matches that of the deck, so as to avoid the phenomenon that the utilization rate of materials is too low.