板结构水下爆炸下的空化特性

Investigation on Cavitation Characteristics of Plate Structure Subjected to Underwater Explosion

针对水下爆炸过程中产生的空化效应会对舰船板结构产生二次加载作用,对结构的毁伤不可忽略,并且空化特性与爆炸的方位角和板的曲率等情况显著相关。采用实验与数值模拟相结合的方法,研究了不同爆炸方位角和不同板曲率对空化特性以及板的动态响应的影响;通过对比不同爆距下的气泡和空化演化过程,验证了数值方法的准确性。结果表明,爆炸方位角在0°~90°之间时,空化区域的体积随方位角的增大先减小后增大,气泡和射流的方向受板的影响向板偏移;气泡脉动水射流和空化的耦合作用对板的动态响应占主导作用,方位角等于60°时可达总应变的73.15%;爆炸方位角会影响板的动态响应,临界方位角在45°附近,此时板的位移和等效塑性应变最大;板的曲率会显著影响空化现象,曲率越大空化现象越难发生,空化区域体积越小,板的动态响应随曲率的增大而减小,且减小率也随之减小。

The cavitation effect generated during the underwater explosion will have a secondary loading effect on the ship plate structure,and the damage to the structure cannot be ignored.The cavitation characteristics are significantly related to the azimuth angle of the explosion and the curvature of the plate.The effects of different explosion azimuth angles and plate curvatures on the cavitation characteristics and the dynamic response of the plate were studied by combining experimental and numerical simulation methods.The accuracy of the numerical method was verified by comparing the bubble and cavitation evolution process under different detonation distances.The results show that when the explosion azimuth angle is between 0°and 90°,the volume of the cavitation area decreases first and then increases with the increase of the azimuth angle,and the direction of the bubble and the jet shifts to the plate due to the influence of the plate.The coupling effect of bubble pulsating water jet and cavitation plays a dominant role in the dynamic response of the plate.When the azimuth angle is 60°,it can reach 73.15%of the total strain.The explosion azimuth angle will affect the dynamic response of the plate.The critical azimuth angle is near 45°,where the displacement and equivalent plastic strain of the plate are the largest.The curvature of the plate will significantly affect the cavitation phenomenon.The larger the curvature is,the less likely the cavitation phenomenon is to occur,and the smaller the volume of the cavitation area is.The dynamic response of the plate decreases with the increase of curvature,and the reduction rate also decreases.