As one of the important structures to improve the vitality of ships,the tank structure plays an important role in the anti-knock performance of the hull structure.The underwater explosion process has high transient and high complexity,and the interaction between impact load and structure has always been the focus and difficulty of research.The real ship test is the most effective method to study the impact resistance of the hull structure.Model tests based on similarity theory play an important guiding role in anti-knock research and protection design of hull structures.Firstly,the form of underwater explosion load is expounded,and the calculation and rounding method of the underwater explosion shock spectrum are discussed.While taking into account the loading state of the tank,the distribution characteristics of the shock environment along the length of the cabin with different deck structures in the tank are calculated and analyzed respectively.The distribution law of the impact environment of the cabin structure under different impact factors is studied,and the results show that when the impact factor increases,the high-frequency response is most affected.Considering the influence of the rigid body motion of the cabin on the distribution law of the shock environment,it is found that the rigid body motion has a significant impact on the mid-low frequency band of the shock spectrum,but has little effect on the high frequency band.Secondly,the law of shock wave propagation is analyzed by numerical method,and the propagation of underwater explosion shock wave in the cabin structure and the surrounding watershed is explored.Then,the plastic deformation and energy absorption of the local structure of the tank under the empty and fully loaded state of the tank are studied.Finally,the effects of different loading conditions on the plastic deformation,velocity peak and structural energy absorption of the liquid-containing tank are discussed.The results show that the reduction effect of the permanent plastic deformation of the outer plate is obvious with the increase of the liquid level in the tank.Considering the reduction of resource consumption,60%of the tank can achieve the best anti-knock energy absorption effect.Thirdly,the hull cabin test was carried out,and the test data of the free+free field pressure results and the dynamic response and damage results of the cabin structure were obtained,and the characteristics of the shock response law of the empty and full load of the liquid-containing cabin structure under the action of underwater explosion were studied.,and compared the test results with the numerical results,and explored the differences and causes of the failure modes of the hull structure containing liquid tanks under different loadings.Finally,the dimensional analysis method is used to analyze the similarity of the shock wave load of the underwater explosion,and the similarity criterion related to the shock wave is derived,and the correctness of the similarity rate of the shock wave load is verified.On the basis of complete similarity theory,the distortion model when single or multiple similarity conditions cannot be satisfied and the prediction method are discussed.Considering the structural parameters and the physical quantities that characterize the dynamic response of the structure,the research on the similarity ratio of structural dynamics under the action of shock wave load is carried out.The hull plate frame and cabin structure are deduced in turn and the prediction value is verified.The similar model results are in good agreement with the prototype dynamic response results after similar processing.Then,considering the situation that the charge amount and the structure size cannot meet the similarity rate condition,the corresponding distortion model is obtained.Curve fitting is performed on the response results of the distortion model to obtain the corresponding relationship between the prediction coefficient and the distortion coefficient.The dynamic response results of the prototype predicted by the distortion model are numerically verified,and the prediction error is within 15%. |