船舶上层建筑开口群结构强度试验与外压载荷等效加载方法

Strength test of ship superstructure opening group structures and equivalent loading methods for external pressure

[目的]旨在探究外压载荷等效加载对船舶上层建筑开口群结构应力计算结果的影响。[方法]首先,构建三维密闭缩比结构模型,通过内部抽真空方式模拟结构所受均布外压载荷,以及开展结构强度试验。通过数值仿真分析,研究点、线和面等不同等效加载方式下结构附近典型部位的应力分布。然后,对比各加载方式下仿真应力值和试验值,探讨等效多点加载时加载点间距对结构应力分布的影响。[结果]结果表明,等效弹性面及等效线两种加载与实际外压载荷作用吻合较好;在加载点间距与开口周长比达到0.074时,等效点加载所得结构测点应力与试验结果吻合较好;等效刚性面加载下结构测点应力与试验结果平均相对误差较大。[结论]等效弹性面加载、等效线加载和具有一定密度的等效点载荷加载可较好地模拟实际外压载荷加载的作用,而等效刚性面加载会导致开口角隅或边中点等部位应力严重偏低。

[Objectives]Aiming at exploring the influence of external pressure loading on the stress calculation results of the opening group structures of ship superstructures, a study on external pressure loading methods and strength tests is carried out.[Methods]First, a three-dimensional airtight superstructure model with opening groups is made on which strength tests are done through internal vacuum extraction to simulate external pressure loading. Numerical simulation analysis is then carried out to study the stress distribution of typical locations in the superstructure under different equivalent loadings(i.e., equivalent point, linear and surface loadings). A comparison of stress levels between the test results and simulation obtained from different loading methods is done to explore the influence of loading point spacing on the stress distribution of opening group structures via equivalent multi-point loading.[Results]The results show that equivalent elastic surface and linear loading are in good agreement with the actual external pressure loading. When the ratio of loading point spacing to opening circumference reaches 0.074, the stress levels of the measuring points predicted via the equivalent point loading method correlate well with the test results. The relative average error between the stress levels of the measuring points predicted via the equivalent rigid surface loading method and test results is much greater.[Conclusions]The equivalent elastic surface, linear and point loading methods with a certain density can simulate the actual external pressure loading well, while the equivalent rigid surface loading method causes the stress levels at the corners of the openings or middle points of the edges to be extremely low.