| Large surface ship serves as a significant support to promote the Navy to walk towards the deep blue and a major factor influencing the success or failure of sea warfare.The quantum leaps in explosive charge mass and hit accuracy of anti-ship missiles greatly threaten the vitality of large surface ships.This paper is based on the background that the semi-armor piercing anti-ship missiles penetrate into and then blast inside the large surface ships.Aimed at illustrating the mechanism for damage and protection of cable internal warhead blast,this paper provides reference for the blast resistant design of large surface ships and is of great significance in basic researches and engineering guidance.In accordance with the overall concept of “load-characteristics-response-protection”,experimental,theoretical and numerical simulation methods are combined to investigate the key related issues,including loading characteristics of cabin internal warhead blast,dynamic failure characteristics of shipbuilding steel,dynamic response of cabin structure under cabin internal warhead blast,protection mechanism of water spray and liquid cabin on cabin internal blast loading,etc.The major research work and conclusions are as follows:Part One,Research on loading characteristics of cabin internal warhead blastFirstly,the physical process of formation of warhead blast fragments is analyzed.The one-dimensional expansion ring is used as the analysis means to reveal the key influence of Mott unloading wave in fragment formation process.On this basis,the fragment quantity and mass distribution as well as initial expansion velocity are analyzed.Then,the influence which the shell thickness has on failure models is studied and its mechanism is revealed in combination of changes in stress states.Furthermore,based on the chemical reaction process of explosive blast,the generation mechanism of quasi-static pressure,which is the most significant pressure load for cabin internal blast,is analyzed and corresponding prediction model is given.Then,the generation mechanism and theoretical model of quasi-static pressure are verified by tests.On this basis,the equivalent bare charge theoretical model for shelled warhead is presented based on equivalence to quasi-static pressure.Later,Type 2 warhead blast experiment is carried out and then the physical process for warhead fragmentation and its impact on the structure is analyzed.Then,the fragment loading and pressure loading characteristics are studied and the revised bare charge theoretical model based on impulse and quasi-static pressure is verified.Part Two,Research on dynamic failure characteristics of shipbuilding steelFirstly,the “cliff phenomenon” of shipbuilding steel in low-stress triaxiality range is analyzed and the deficiencies in classical constitutive model are pointed out.In combination of the deduction and analysis of stress states,21 test samples and experimental rigs are designed,including plate gap tension,combined tension-shear impact,bulge deformation and dynamic tension,etc.Then,based on numerically-related experimental techniques(DIC),the dynamic failure characteristics of shipbuilding steel under complex stress states are obtained.Later,a dynamic damage failure constitutive equation considering variables,including temperature,strain rate,stress triaxiality and Lode angle,is proposed.In addition,the secondary development of sub-program is carried out.The new dynamic damage failure constitutive model which has been verified is applicable to the prediction of damage in plates in complex stress states under penetration residual velocity and blast loading.Part Three,Research on dynamic structural response of cabinFirstly,the dimensional analysis method is adopted to analyze the similarity relationships among shock wave,impulse and quasi-static pressure.Based on the weak-reinforcement deformation mode and dynamic characteristics of shipbuilding materials,a revised dimensionless quantity for cabin internal blast is presented.In addition,the experimental study on dynamic response of plates and reinforced plates under cabin internal blast loading is carried out and then their failure modes are obtained,which verifies the revised dimensionless quantity.Furthermore,the pre-fabricated hole plate is adopted to carry out the experimental and numerical simulation study on dynamic response under combined blast wave and fragment loading.Then,the influence which the hole penetration shape has on local stress states,stress concentration coefficient and failure modes,is analyzed.Then,the experiment on the cabin internal blast damage of shelled warhead in multi-cabin structure is carried out and the physical process for damage of blast cabin and blast avalanche of nearby cabins is analyzed.Then,the failure modes of typical structures,including cabin wall,deck and cabin door,are obtained.In addition,the weak links of common cabin structure are pointed.Part Four,Research on protection mechanism of water spray and liquid cabinFirstly,the shock wave tube is adopted to carry out experiments on the fragmentation and atomization mechanism of single droplet under shock wave loading.In combination of theoretical analytic methods,the major factors influencing atomization and fragmentation are obtained.On this basis,the methods,including level set,GFM and AMR,are combined to carry out the analysis on the influence which shock wave loading has on droplet deformation and flow field.In addition,the experimental analysis on the attenuation effect which passive water spray has on pressure load of cabin internal blast.It is verified that the water spray has excellent attenuation effect on shock wave peak,impulse and quasi-static pressure.In combination of the chemical reaction process of cabin internal blast,the mechanism that the water spray suppresses the cabin internal quasi-static pressure by mainly suppressing the secondary combustion is revealed.Finally,the experimental study on the attenuation of cabin internal blast fragment load in liquid cabin is carried out.Then,the mechanism that the liquid cabin dissipates the energy of fragment energy by forming shock wave,delayed flow and bubble collapse shock wave.In addition,the theoretical analysis model is verified and the failure modes of liquid cabin wall are obtained.Then,an interlayer liquid cabin structure to prevent overall failure under fragment loading is proposed and its mechanism is analyzed.Under the support of National Key Basic Research Foundation(No.613157),National Natural Science Foundation(No.51509196),National Defense Basic Research Foundation(No.B1420133057),Training Foundation for Outstanding Doctoral Dissertations(No.2014-yb-20)and National Key Laboratory Open Foundation(No.LNM201505),this paper carries out a systematic research on the damage and protection mechanism of cabin internal blast loading of anti-ship missiles,reveals the damage and protection mechanism and establishes the theoretical model for analyzing relevant issues as well as analyzes the major influencing factors.The achievement of this paper can be applied to evaluation and protection design of large surface ships as well as provide theoretical support and technological reserve for practical engineering applications. |
PDF Full Text Request