Research On Structural Damage Characteristics And Impact Response Propagation Law Of Cabin Internal Explosion

In recent years,with the rapid development of anti-ship missile technology,the range and power of missiles have been significantly improved,posing a huge threat to large surface ships sailing at sea.When the missile penetrates the deck,enters the cabin and implosion occurs,it will generate loads such as high-pressure shock waves,reflected waves and quasi-static pressure,which seriously threaten the vitality of the ship.This article mainly studies the damage characteristics and vibration propagation law of the explosion structure in the cabin,and provides some references for the ship's protective design.Firstly,the basic theory of airborne shock waves will be understood,such as the basic propagation law of shock waves in air and reflection on walls.The empirical formulas for overpressure and quasi-static pressure in the free field air explosion also will be summarized in this paper.Then the ALE method will be introduced,including governing equations and calculation steps.Finally,using the ALE method in LS-dyna software to simulate the process of free-field air explosion,indoor explosion in a closed cabin,and flat-plate close-up air explosion.Comparing the calculation results with empirical formulas and experimental results to verify that the ALE method in dealing with the explosion problem in the cabin is reliable.Secondly,in the process of cabin explosion,the propagation and reflection of shock waves in the cabin are studied,and the influence factors of static overpressure are analyzed.Firstly,the foreign explosion test process is simulated,and the numerical calculation results are compared with the test results.It is verified that the ALE method can accurately simulate the complex reflection process of the shock wave in the cabin.Then the cabin models of different sizes are established,and the effects of double-sided and trihedral corners on the convergence of shock waves are analyzed under different aspect ratios.Finally,the influencing factors of the static overpressure peak were analyzed,including the area of the pressure relief hole,the relative position of the explosion point and the pressure relief hole,and the post-combustion phenomenon.Thirdly,the finite element model of the cabin structure with two different structural types is established,and the influence of the existence of the frame structure on the protection performance of the cabin is studied.First,the implosion process of the cabin was simulated,and two typical positions in the ship and the side were selected for calculation.Then analyze the damage of the structure of the lower section of the explosion at different positions and the impact environment in the cabin.The damage includes the damage modes of the main structures such as decks,bulkheads and frames.The resulting plastic area and breach area.The impact environment mainly includes impact acceleration and spectral acceleration values.Finally,the final damage effect of the cabin sections under the two types of working conditions is integrated,and the protective capabilities of the two types of cabin sections are evaluated to provide a reference for the ship's protection design.Finally,a model of the whole ship is established,and the charge of the conventional missile warhead is used as a reference.The mass of TNT explosive is selected between 50kg and 300kg to simulate the implosion process of the whole ship.Summarize the distribution of the impact acceleration of the deck structure,and use the calculated results to fit the formula for quickly calculating the peak acceleration of the deck.At the same time,it was found that there was a"paper window effect" during the implosion of the entire ship,that is,there was a limit value for the energy transmission to the distance along the structure.When this value was reached,the impact environment of the distant structure did not change significantly with the increase of the amount of medicine.