Research On The Theory And Application Of The Interaction Of Ship And Equipment Subjected To Underwater Explosion Load

Shock spectrum is a widely used method to describe the shock environment of submarine and surface ship equipment.It is mainly used to predict the possibility of equipment failure and set up the design spectrum of equipment assessment.The shock spectrum data of a position under different working condition in the real ship test can be used to get the design spectrum of equipment,on the basis of this,the impact resistance standard is formed,and the impact assessment is carried out for pre service ship-based equipment.Only the equipment that is checked can be applied to the actual ship structure.The accuracy of the design spectrum is therefore related to the vitality of the whole ship.At present,the anti shock standard of our country is mainly based on the design spectrum of the German and American Standard,and it is lack of experimental verification for the key index data in the impact standard.Therefore,it is difficult to guarantee the rationality of its assessment method.This article is mainly aimed at the above problems.The phenomenon of “spectrum dip” between shipboard equipment and hull structure is studied in depth,and the influence rule of different factors on equipment design spectrum is analyzed.The purpose is to provide certain basis for revising the standard of shock resistance in China.The specific contents are as follows:Firstly,the basic principle of shock spectrum is introduced,and its validity is verified in the single degree of freedom and multi degree of freedom system.At the same time,it points out the importance of the pseudo velocity shock spectrum in the shock resistance of ship equipment,and explains its theoretical basis from the angle of modal velocity and energy respectively.Then,based on the mechanical impedance method,the cause of the formation of the spectrum dip is explained,and the control factors of the spectrum fall are put forward.Secondly,the differences between the current two methods of design spectrum(German and US military)are reviewed,and the shortcomings of the two methods are pointed out.A simple two degree of freedom and four degree of freedom theory model is used to explain the origin of the design spectrum value.Then,the simplified equipment is installed on the ship model,and the influence of different factors on the design spectrum and the submode coupling of the multi degree of freedom system are investigated.Thirdly,based on the coupling effect between the equipment and the hull,a deck simulator is designed with reference to the American MIL-S-901 D,and its natural frequency is analyzed.The impact environment of non installation equipment,installation equipment and equipment weight change on deck simulator under different natural frequencies is calculated respectively.It is concluded that the impact input of the equipment can be adjusted in any frequency band by adjusting the inherent properties of the deck simulator.Finally,the structure of a rectifier cabinet is studied in this paper,in which the impact machine is used as the loading equipment;the corner and internal shock acceleration of the cabinet are tested in the four impact velocities.The numerical value and distribution of impact environment are obtained.The numerical model is modified by the experimental data,through the simulation of finite element software,the impact environment of each electrical equipment are obtained and to provides the basis for the failure mode and protection of the ship electrical equipment.