Research On Structural Damage Characteristics And Impact Environment Of Multiple Weapons Exploded Underwater

In recent years,as scholars pay more and more attention to the research of ship vitality and many new technologies and structures are used,the ship’s anti-attack capability has been significantly improved.For example,the Naval Standard of U.S.points out requirements that large surface ships must withstand at least 3 torpedo contact explosions without sinking while the aircraft carriers must withstand at least 14 torpedo contact explosions without sinking.Most of the related studies in the published literatures focus on the damage of single weapons to ship.However,the research on the damage of multi-weapon underwater explosion to structure is rare and the relevant mechanism has not been fully revealed.Therefore,based on the Arbitrary Lagrange-Eulerian(ALE)algorithm,this paper studies the damage characteristics and impact response of ship structures under multiple underwater explosion loads,aiming to providing a reference for the research of ship anti-explosion and anti-impact.The specific contents are as follows:This article firstly elaborates the physical phenomena of underwater explosion shock wave and bubble pulsating load features,to single and multiple weapons attack damage situation of structure of underwater explosion is reviewed,this paper discusses the basic principle,the calculation methods of the ALE and the shock wave of underwater explosion load,the load of bubble and the structure of the underwater explosion when damage is simulated.Comparing with the empirical formula and related experimental results,the effectiveness of ALE method in solving structural damage caused by multiple underwater explosions is verified.These results lay a foundation for the subsequent research.Secondly,the damage characteristics of typical plate structures caused by two near-field underwater explosions are studied,and the dynamic response of plate structures in the stage of two underwater explosion shocks and bubble pulsation is described in detail.Through the working condition of control group,from the strain and displacement response of the structure and the final residual deflection deformation,this paper analyzed the damage effect of different explosive combination on plate frame structure.Combined with the energy absorption of two underwater explosion plate structures,this paper studied the effect of different explosive combinations and explosion sequence on the damage effect of the structure.Then,the finite element model of the whole ship is established and the damage characteristics of the whole ship structure caused by underwater contact explosion of multiple weapons are studied.In this paper,the dynamic response process of the typical ship during the initial underwater explosion is described in detail,and the second underwater explosion numerical simulation is carried out based on the residual stress and strain of the structure after the initial underwater explosion.By comparing the size of structural breach,effective plastic area and final residual deflection,the final damage state of the structure during underwater contact explosion of two weapons is analyzed.Then,by changing the space position of secondary explosive charge,this paper discussed the optimal position of secondary explosive charge for structural damage.Finally,this paper studied the impact response of the whole ship structure in the case of underwater contact explosion of multiple weapons,and discussed the distribution law of the ship’s impact response along the depth and length direction during the first and second underwater explosion,and compared and analyzed the similarities and differences of the ship’s impact environment in the case of two successive underwater explosions.This paper also explored the influence of ship bottom breaches on the distribution of ship impact environment along the length direction,which provides a reference for ship impact design.