水下爆炸条件下自由场压力载荷时频特征分析

  目的  加筋板结构参数对其抗水下爆炸性能有重要影响，需要对加强筋高度、加强筋数目、加强筋厚度等参数的具体影响进行分析。  方法  基于耦合欧拉−拉格朗日（CEL）方法开展数值模拟研究，分析加筋板结构参数对结构抗爆性能的影响。基于加强筋在水下爆炸载荷作用下的吸能规律，引入系数来表征加强筋的影响程度，提出一种考虑加强筋系数的等效厚度计算方法。  结果  对加筋板抗水下爆炸能力影响显著的3个因素分别是加强筋高度、面板厚度和加强筋厚度，翼板厚度影响较小。在结构质量改变量相同的情况下，横/纵向加强筋高度对加筋板破口面积的影响是翼板厚度的2.5倍，面板厚度和横/纵向加强筋腹板厚度对破口面积的影响是翼板厚度的2倍。随着加强筋高度、加强筋数目、加强筋厚度等参数的增加，加筋板结构强度和抗水下爆炸能力增强，损伤程度减小。采用考虑加强筋系数的等效厚度计算方法得到的相关性系数为−0.94，该方法能较好地反映加筋板抗水下爆炸的能力。  结论  研究结果可以作为舰船结构抗水下爆炸载荷评估的基础，为舰船抗爆结构设计提供参考。

Continuous simulation of the whole process of underwater explosion based on Eulerian finite element approach

  Objectives  The structural parameters of the stiffened plate have an essential influence on its resistance to underwater explosion. It is necessary to analyze the specific influence degree of different parameters such as the stiffeners' height, number, and thickness.   Methods  A series of numerical simulations were performed using the CEL method. Then, the influence of stiffened plates' structural parameters on their resistance to underwater explosion was analyzed. Based on the energy absorption law of stiffened plates underwater explosion load, a coefficient was introduced to characterize the influence degree of stiffeners. A calculation method of equivalent thickness was proposed considering stiffener coefficients.   Results  The height of the stiffener, the panel thickness, and the stiffener's thickness have remarkable effects on the resistance to underwater explosion. In contrast, the thickness of the wing plate has an insignificant impact. Under the condition of the same amount of structural mass change, the influence of the height of the transverse/longitudinal stiffener on the damaged area of the stiffened plate is 2.5 times that of the wing panel thickness. The impact of the panel thickness and the thickness of the transverse/longitudinal stiffener on the damaged area is twice that of the wing panel thickness. With the increase of the stiffeners' height, number, and thickness, the structural strength and resistance to underwater explosion of the stiffened plate are enhanced, and the damage degree of the stiffened plate is reduced. The correlation coefficient of the proposed equivalent thickness calculation method considering the stiffener coefficient is −0.94. The method can adequately reflect the stiffened plate's resistance to underwater explosion.   Conclusions  The research results can be used as the basis for evaluating the ship structure against underwater explosion load and provide a reference for the design of the ship's anti-explosion structure.