Research On The Mitigation Of Internal Blast Loading Using Water

Since the advent,anti-ship missiles gradually become important threat of the surface warship for the development of concealment,accuracy,and explosive charge.When penetrating the surface warship structure,the anti-ship missile will blast in ship cabin and release internal blast loading.The energy of internal blast loading will cause serious damage on ship structures.Due to the restriction of scale and tonnage,the middle and small surface warship are not allowed to be armed with a lot of protect armor structures.There is urgent need to explore new way of anti-blast in order to improve the vitality of the surface warship.Water is rich,non-toxic,and harmless and has good endothermic capacity.It has caused wide attention of scholars both at home and abroad if water has the capability of anti-blast.Therefore,it has practical significance to research on the mitigation of internal blast loading using water.Centered on the mitigation capability of water for internal blast loading,the following main researches were accomplished:(1)Research on the factors effecting the mitigation of internal blast loading using water.The mitigation of internal blast loading by water wall was calculated with the AUTODYN-2D axial symmetry model.Parametric study was also performed by the numerical model.The effects of location of water wall,explosive charge and water mass(thickness of water wall)on the blast mitigation were clarified,and the trend of shock wave pressure peak effected by the factors was analyzed.The result shows that the overpressure peak attenuation ratio increased at first and then decreased with the explosive charge increasing.When the thickness of water wall increased,the overpressure peak attenuation ratio also increased at first.However,if the thickness further increased,only small gains were achieved.(2)Research on the mitigation mechanism of internal blast loading using water.Based on water droplet,breakup and evaporation of water were investigated theoretically,and the expressions of breakup energy,kinetic energy and thermal energy were obtained.The experiment of the mitigation of internal blast loading using water was carried out and propagation of blast was captured by high-speed photography.The interaction between water and explosive product was analyzed,and the blast mitigation mechanism was discussed.The result shows that the main mitigation mechanism includes two parts: energy absorption and blast reaction inhibition.Consequently,water can effectively reduce the strength of the explosion.(3)Research on mitigation effect on internal blast loading using water.Both numerical simulation and experiment were carried out to investigate the mitigation effects.The numerical simulation was computed by AUTODYN-3D model,and the overpressure peak,quasi-static pressure peak,and impulse of the blast shock wave were calculated with or without water.The results were compared with above-mentioned mitigation experiment.According to the research,both numerical simulation and experiment results indicated that the water provided good mitigation effect on internal blast loadings the overpressure peak was attenuated up to 71.2%.Therefore,water has the potential to be widely used in the areas where potential blast attacks are expected.These studies demonstrated the mitigation of internal blast loading using water and provided a theoretical basis and practical guidance on the problem.They also provided references of anti-blast for surface warship.