分析小型水下圆柱壳结构冲击响应的一种近似方法

THE IMPACT RESPONSE OF THE SMALL CYLINDRICAL STRUCTURE SUFFERED FROM UNDERWATER EXPLOSION

根据小型水下圆柱壳状结构受爆炸冲击后散射现象严重的特点 ,提出了一种新的冲击加速度的近似计算方法。首先把带加强筋的柱壳结构简化为光滑柱壳 ,并将冲击波分解为不同频率谐和平面波的迭加 ,然后 ,采用耦合模态法分析了受爆炸冲击水下圆柱壳状结构周围的散射场 ,求出了圆柱壳状水下结构的表面接收压力 ,进而分析其受到爆炸冲击后的冲击加速度 ,并研究了结构的弹性变形、材料特性对冲击加速度响应的影响。工程应用实例的分析结果表明 ,该方法具有物理概念清晰 ,运用方便 ,准确度高的特点 。

According to the anti_explosion characteristics of small cylindrical structures under water,in which the incident wave scattering is too heavy to be ignored,an approximate method of the shock acceleration analysis is developed.A cylindrical structure with ribs is modeled as an ideal cylinder shell,which has the same diameter and the same lower orders vibration modes as the practical structure.The shock wave is decomposed into harmonic plane waves with various frequencies.A coupled mode method is applied to study the scattering field surrounding the cylindrical structure,from which the receiving pressure on surface can be obtained.The shock acceleration response of a structure suffered from underwater explosion can be calculated,with consideration of the effect of elastic distortion and material characteristics.It is found that the shock acceleration response of the structure with elastic distortion is obviously smaller than the one with no elastic distortion.The lower the velocity of the elastic wave in a structure is,the smaller the shock acceleration will be,so the elastic distortion should be considered in analyzing shock acceleration response of underwater structures to improve the analysis precision.The procedure can be understood easily,and can be applied to analyze shock accleration respanse of small cylidrical structures impacted by shock wave,where the incident wave scattering of structures plays a key part.