Study on directional enhancement effect of underwater explosion for cylindrical explosive with large length-to-diameter ratio and structural response of nearby water-back plate

Abstract

In order to study the directional enhancement effect of underwater explosion for cylindrical explosive with large length-to-diameter ratio, based on the experiment and ALE method, the influences of length-to-diameter ratio on the shock wave and bubble load as well as the structural response of nearby water-back copper plate are analysed. Meanwhile, the influence of the explosive weight on the directional enhancement effect is considered. Some instructive conclusions can be drawn. i) As the length-to-diameter ratio increases, the propagation velocity increases in the radial direction and decreases in the axial direction, and the high-pressure area gradually concentrates in the radial direction. ii) In the range of 1:1–8.2:1, increasing the length-to-diameter ratio enhances the shock wave and bubble load in the top direction and facilitates the formation of a stable bubble jet in this direction. iii) Increasing the length-to-diameter ratio enhances the damage effect of combined load in the top and bottom directions. When the length-to-diameter ratio increases from 1:1 to 8.2:1, the maximum plastic deformation of the water-back copper plate is increased by 26.2%. iv) The directional enhancement effect will be more obviously if the maximum bubble radius is larger than the distance between the structure and the explosive.