水下爆炸载荷作用下加筋双层圆柱壳结构优化数值模拟

Numerical simulation of optimization of reinforced double-layer cylindrical shell structure under underwater explosion loading

为研究水下爆炸载荷对加筋双层圆柱壳的毁伤特性,采用有限元方法构建5段和10段加筋双层圆柱壳结构模型,对比研究不同冲击因子(0.50、0.33、0.28)、距爆源不同距离(2.00、3.03、3.57 m)的3种工况下,5段和10段加筋双层圆柱壳结构的载荷特性和响应特性,选择典型测点测量加速度、速度和位移曲线。结果表明:在工况1下,加筋双层圆柱壳模型结构变形最明显;3种工况下,水下爆炸载荷大多作用在加筋双层圆柱壳的外层壳,外层壳分担大部分的爆炸冲击应力,对内层圆柱壳起到较好的保护作用,2种结构冲击变化特征相似,10段加筋双层圆柱壳的抗冲击性优于5段加筋双层圆柱壳;加速度以x方向为主,爆炸后x方向的加速度在前0.001 s振荡达到峰值后又迅速振荡减小,y方向的加速度变化较小,z方向的加速度几乎未变;5段加筋双层圆柱壳模型内外层壳母线中心点的速度峰值比两端测量点大,且爆炸后迅速达到速度峰值,内层壳测点速度峰值始终小于外层壳;位移迅速增至峰值后减小至固定值。冲击因子越大,距爆源距离越小,载荷对加筋双层圆柱壳结构的冲击作用越大;在相同冲击因子下,整体质量一定,加筋越多,加筋双层圆柱壳抗冲击特性越强,抗冲击效果越明显。

To study the damage characteristics of reinforced double-layer cylindrical shells under underwater explosive loads,finite element calculation methods are used to construct models of 5-section and 10-section reinforced double-layer cylindrical shells.A comparative study is conducted on the load characteristics and response characteristics of 5-section and 10-section reinforced cylindrical shell structures under different impact factors and distances from the explosion source,selecting typical observation points to measure acceleration,velocity,and displacement curves.The results show:under working condition one,the model structure deformation is most pronounced;under three conditions,underwater explosive loads mostly act on the outer shell of the reinforced double-layer cylindrical shell,with the outer shell bearing most of the explosion impact stress and providing good protection for the inner cylindrical shell.The two structural impact characteristics are similar,with the impact resistance of the 10-section reinforced cylindrical shell being superior to the 5-section reinforced cylindrical shell;acceleration is mainly in the x-direction,with the x-direction acceleration reaching a peak shortly before 0.001 s after the explosion and then rapidly oscillating and decreasing.The y-direction acceleration changes are minimal,and the z-direction acceleration remains unchanged;the velocity peak at the center point of the inner and outer shell spines of the 5-section reinforced double-layer cylindrical shell model is greater than that at the two ends measurement points,and after the explosion,it quickly reaches the velocity peak,with the velocity peak of the inner shell measurement point always being smaller than that of the outer shell;displacement increases rapidly to a peak and then decreases to a fixed value.The larger the impact factor and the closer the distance from the explosion source,the greater the impact of the load on the cylindrical shell structure;under the same impact factor,with constant overall mass,the more reinforcements there are,the stronger the impact resistance of the reinforced double-layer cylindrical shell,and the more pronounced the impact resistance effect.