水下近距和接触爆炸载荷作用下板架结构动态响应机理

Mechanism of Dynamic Responses of Grillage Structures under Loads of Close-in and Contact Underwater Explosions

以某型水面舰船防护结构的膨胀舱为原型设计板架试验模型,依药量和爆距不同进行7个工况的水下近距和接触爆炸试验。采用光子多普勒测速系统测量模型典型位置的速度时程,收集试验产生的飞片,并对试验后板架的破口形态进行记录。结合数值方法对试验结果进行对比分析,验证试验结果的一般性及数值计算方法的准确性。根据试验和数值计算结果对水下近距和接触爆炸载荷作用下板架结构动态响应开展研究。研究结果表明:板架结构容易在加强筋、隔板处发生剪切或撕裂破坏形成飞片,飞片的形成与药量、爆距、板架的结构形式均有密切关系;爆炸载荷驱动下板面上各点速度以爆心投影点为中心沿板面向外呈指数衰减趋势;当爆距大于2倍装药半径后,不同药量在相同的距径比下,板架结构上正入射点处速度峰值基本相当。

This paper designs grillage structure models based on a specific protective structure of a surface ship,and conducts close-in and contact underwater explosion experiments on 10 grillage models under 7 working conditions with various charges and distances.The velocities of typical points are measured with the Photonic Doppler Velocimetry system,the fragments of the grillage structure are gathered,and the damage forms after each experiment are recorded.The experimental results compare well with the numerical results,verifying the generality of the experiment and the accuracy of the simulation.The analyses of experimental and numerical results reveal several conclusions.The grillage structure is susceptible to shear and tear at reinforcing ribs and diaphragm plates,leading to the formation of fragments.The number and weight of fragments depend on the explosive charges,distances,and structures of the grillage.The velocities of points on the surface of the grillage decrease exponentially with increasing distance between the measuring point and center point.The center point is the projection point of the explosive charge on the grillage surface.When the ratio of the explosion distance to explosive charge radius is not less than 2,the velocity of center point remains nearly constant,even though the explosive charge mass changes.