An Experimental Method for Box Girders Subjected to Underwater Explosions Considering the Initial Bending Moment
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摘要: 箱型梁是船舶缩比水下爆炸试验中的常用模型, 但由于材料规格和焊接工艺的限制, 所采用的箱型梁板厚都比按完全缩比的大。过大的板厚使箱型梁具有更大的抗弯刚度, 因此, 采用此类模型进行水下爆炸试验时会低估水下爆炸的威力, 使试验结果很难直观地映射到实际模型。为了抵消过大刚度带来的影响, 文中引入初始弯矩的思路, 建立了一种能实现弯矩幅值和分布可控的箱型梁水下爆炸试验方法。通过试验结果对比发现, 文中所介绍的考虑初始弯矩的箱型梁水下爆炸试验方法能降低模型板厚带来的影响, 可为船舶缩比水下爆炸试验的设计提供参考。Abstract: Box girders are commonly used in underwater explosion experiments on scaled ships. Owing to the challenges associated with materials and welding techniques, the plate thickness of the box girders is always greater than that of a completely geometrically similar model, which leads to increased bending stiffness. Therefore, underwater explosion tests based on these models will underestimate the power of underwater explosions and test results are difficult to map directly to accurate models. To offset the influence of excessive bending stiffness, a method that can easily control the amplitude and distribution of the introduced initial bending moment is proposed. Based on the results of a set of comparative experiments, we determined that the proposed method can reduce the influence of model plate thickness and can be used to study the influence of the bending moment on the underwater explosion responses of box girders. This method can provide a reference for the design of underwater explosion experiments on scaled ships.
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Key words:
- underwater explosion experiment /
- bending moment /
- box girder
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图 1 箱型梁整体及横剖截面示意图
Figure 1. Schematic diagram of the whole and transverse sections of the box girder
图 3 箱型梁剪力和弯矩分布
Figure 3. Shear force and bending moment distribution of the box girder
图 5 悬挂配重wo=17.4 kg时剪力和弯矩分布
Figure 5. Shear and bending moment distribution in hang-weight box girder with hang-weight is 17.4 kg
图 7 箱型梁水下爆炸作用过程典型时刻
Figure 7. Underwater explosion action process of the box girder at typical moment
表 1 箱型梁基本参数
Table 1. Basic parameters of box girder
名称 参数 L/mm 500 B/mm 65 H/mm 50 T/mm 1 s 4 Sy/mm3 2 632.5 I/mm4 4.645×104 σ0/MPa 345 ρs/(kg·m−3) 7 896 Mu/(N·m) 908.2 
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表 2 箱型梁水下爆炸试验工况
Table 2. Conditions of the underwater explosion test of box girder
工况 悬挂配重方式
配重量/kg悬挂位置 配重区域 弯矩极值
/(N·m)|Mm/Mu|/% 1 无配重 0 — — 0.018 0.002 2 两端配重 17.40 0.4L和0.6L (0~0.2)L和(0.8~1)L −14.92 1.643 3 两端配重 10.44 0.4L和0.6L (0~0.2)L和(0.8~1)L −8.95 0.985 4 中间配重 17.40 0.01L和0.99L (0.4~0.6)L 19.18 2.112
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