Panetration Resistance Of Honeycomb Protective Liquid Cabin To High-spced Fragment

The broadside protection structure is the final line of defense to guarantee survivability of the warship.And the liquid cabin,as one of the most critical components,plays a good role in resisting high-speed fragmentation,which is able to effectively absorb the kinetic energy of fragmentation and protect the rear structure.However,the hydrodynamic ram caused by high-speed fragments moving in water will cause huge damage to the liquid cabin.Which will cause it to lose the protective effect.Therefore,it is of great significance to study how to reduce the damage of liquid cabin structure caused by hydrodynamic ram in ship protection.In this paper,the dynamic response of the liquid cabin under the penetration of high-speed fragments was studied by experiment and numerical simulation.Aiming at two stages of shock and cavitation,two methods for attenuating the hydrodynamic ram were proposed.One of them is to use the air interlayer to reflect the propagation of shock waves.The other is to limit the expansion of cavitation by adding a honeycomb structure.The main researches contents are as following:(1)The dynamic response of the liquid cabin under high-speed fragment penetration was studied.A theoretical model of the deceleration effect of the liquid cabin on the fragment was established.Then the penetration test of high-speed fragment to liquid cabin was carried out.The deformation of the front and rear plates of the tank under high-speed impact and the change of the pressure in the tank were studied.And the effects of fragment shape,speed and water content in the tank on hydrodynamic ram were analyzed.(2)The inhibition of the air interlayer on the hydrodynamic ram was studied.A finite element model of the liquid cabin resisting the impact of the fragment was established.It is considered that shock waves will be reflected when they propagate between media with different wave impedance ratios.A method of adding an air interlayer to the liquid cabin was proposed and was compared with the ordinary tank.It was found that the air interlayer contributed to attenuate the propagation of the shock wave in water and reduce the overall deformation of the liquid cabin.(3)The anti-penetration performance of honeycomb sandwich panels was studied.The numerical simulation of the high-speed impact resistance of honeycomb sandwich panels was carried out.The damage mode of the sandwich panel under high-speed impact was analyzed.And the contribution of each part to the kinetic energy absorption of the fragment was compared.Then the effects of panel thickness,core layer height,honeycomb cell side length and wall thickness on the anti-penetration performance of sandwich panels were discussed.Finally,the geometric parameters of sandwich panels with higher specific energy absorption was determined.(4)The attenuation effect of the honeycomb core on the hydrodynamic ram was studied.It is considered that the honeycomb has the good deformation and energy absorption performance.Therefore,protective design for the honeycomb sandwich tank was proposed.And the dynamic response of the honeycomb tank structure under fragment penetration was studied by the numerical simulation.It was found that the honeycomb core can limit the expansion of cavities through its own plastic deformation and reduce damage to cabin caused by hydrodynamic ram.Furthermore,the effects of the placement of the core layer,the side length and thickness of the honeycomb cells on the protective effect are discussed.Finally,according to the porous structure characteristics of the honeycomb,the air was filled into the honeycomb,and a honeycomb sandwich tank structure with an air layer was proposed.