Characteristics of Flow-Field and Sagging Damage of Free-Free Beam Subjected to Underwater Explosion Bubbles

In order to probe into the damage mode and its mechanisms, a box-like beam was designed, and numerical analysis and experimental verification were carried out. In the discussions, how vertical bending load forms was investigated, and the properties of flow-field were analyzed in details when explosion bubble oscillates, how explosion parameters affect the dynamics of beams was attained, and the basic condition for beam sagging damage was initially proposed. The results show that there exists a low-pressure zone like a concave in the fluid between beam and explosion bubble when the bubble contracts in the near-field, and the low-pressure field causes the sagging damage. If the parameter of , the ratio of stand-off to maximum bubble radius, meets 12.5, explosion bubble will possibly cause beams damage into sagging condition. The smaller the value of parameter , the greater the impact damage.