Research On Shock Environment Characteristics Of Surface Ship Subjected To Underwater Explosion

Shipboard equipment plays an important role for a warship during the modern war because they will undergo complicated dynamic response under underwater explosion.The requirement for anti-shock criteria must be satisfied during the design in order to make sure of the serviceability of equipment.The shock environment of a warship could provide reference for the anti-shock design and assessment of equipment,so research on characteristics of shock environment is the basement of improving the level of anti-shock criteria and the ability of anti-explosion and anti-shock for whole ship.Considering that the standards of our country are mainly drawn lessons from other countries,the technology foundations and criteria of setting standards are not clear.Therefore,it's of theoretical and practical significance to seek and look for the relationships between underwater explosion load and shock environment by studying the shock environment characteristics of different tons of ships,mass and installation frequency of equipment under underwater explosion.In this paper,spring oscillators were developed to simulate the equipment on board,and the second-order Doubly Asymptotic Approximation?DAA₂?was adopted to solve fluid-structure interactions.The dynamic response of spring oscillators were transformed into shock environment.From the aspects of installation area,ship type,mass of equipment and frequency characteristics of foundation,the distribution and variation law of shock environment under the influence of these factors were analyzed.The specific research methods and content are as follows:?1?Based on an actual ship experiment,the influence of the main damping parameters in the DAA method on the calculation results was studied.A reasonable combination of damping parameters was obtained and the results of shock response at the typical installation location were calculated.The influence of relevant parameters on the calculation results was clearly defined,which laid the foundation for following work.?2?The shock environment characteristics of surface ship was studied,and different conditions were calculated for different shock environmental factors.The obtained data were concluded and summarized in multiple directions to explore the coupling between different parameters.The shock environment under individual effect or coupling effect of the installation position,the size of ship,and the mass of equipment were performed.The laws of the shock environment under various influencing factors were completely described and summarized.?3?Combine shock spectrum with mechanical impedance theory,and propose the meaning of“shock impedance”according to the different amplification effect of damping at the resonance frequency in the steady-state vibration and shock spectrum.The"shock impedance"of different equipment and foundations were calculated,and the"shock impedance"characteristics of the whole ship model were obtained,which explained the characteristics of the shock environment under complex input conditions.The"shock impedance"was used to analyze the law of shock environment reduction caused by different mass of equipment,and compared with the shock calculation standards and specifications,and pointed out the limitations of the these criteria.The work of this paper explores the characteristics of the chock environment for surface ships under underwater explosion.The"shock impedance"proposed in this paper can be used to describe the characteristics of the shock environment and the shock response reduction caused by the mass of equipment,and provides a technical support for anti-shock design of equipment.