Study On The Damage Performance Of Structure Under The Combined Action Of The Shaped Charge Jet And The Explosive Bubble

With the enhancement of explosion-proof and sinking resistance of ships,the shaped charge torpedo with small mass and strong damage has gradually widely used in anti submarine.The shaped charge warhead will produce the shaped jet and the explosion bubble,in which the shaped charge jet can easily penetrate the shell,and further damage the internal structure while reducing the tightness of the submarine.Then,the explosion bubble will further increase the damage degree of submarine structure on the basis of the damage results of the shaped jet.In this paper,combined with the AUTODYN multi-material fluid-structure coupling method and the small-equivalent underwater explosion experiment,the structural damage characteristics under the combined action of the shaped jet and the bubble are studied,and the exploration of the combined damage mechanism of the two loads is completed.It can provide a reference for the research of the torpedo light-weight and high-efficiency destruction performance design.Firstly,by comparing the velocity,the perforation size of the shaped jet and the radius,the period of the bubble load under different grid sizes,the grid convergence problem of the multimaterial fluid-structure coupling algorithm in simulating these two loads is analyzed.After discussion,the mesh size that can not only ensure the calculation accuracy but also improve the calculation efficiency is obtained.Then,the numerical calculation results are compared with the experiment results in the literature,the calculated value of the Rayleigh-Plesset equation and the Cole bubble pulsation empirical formula,the accuracy of the algorithm in calculating the shaped jet load and the bubble load is verified.On this basis,this paper studies the influencing factors of the damage performance of the shaped jet,and establishes a numerical calculation model for the damage to submarine hull structures caused by the shaped jet.The influence of the liner type and the thickness of height water layer on the damage performance of the shaped jet is analyzed,and the shape,the velocity and the perforation size of the shaped jet under different influencing factors are received.It is found that for different shells and thicknesses of height water layer,the different types of liner and thicknesses of water layer should be used to enhance the damage capability of the weapon.Then,the effectiveness of the multi-material fluid structure coupling method to calculate the bubble load near the porous structure is further verified by the small equivalent underwater explosion experiment.And based on the perforation results of the shaped jet,the numerical calculation model of the coupling between underwater perforated target and explosion bubble is established.At the same time,the fluid-structure coupling process between explosion bubble and single-layer perforated back air target is investigated,and the effects of different prefabricated hole sizes on the damage results of target and the characteristics of detonation gas flow and water jet load in the structure are obtained.Finally,aiming at the combined action of the shaped jet and explosion bubble,the continuous damage calculation model of the two loads on the structure is established.Besides,the coupling process and damage results of the two loads and single-layer back air target are given.After that,it is compared with the damage results of single load and the initial combination of two loads,the damage mechanism of the structure under the combined action of the shaped jet and the bubble load is revealed.