Research On Anti-shock Characteristics Of Supercharged Boiler On Board

The non-contact underwater explosions threaten the warship survivability more and more fiercely at present. Under the condition of ship structure failure, the power insubmersibility requires the power equipments to be undamaged to survive, or even to be able to accomplish the battle mission. Hence the shock resistance of ship equipments relates to the ship survivability directly, especially for the type A equipments. Including the self-shock resistance of equipments and impact damper, the shock resistance of warship equipments should be priority studied, where the equipment self-shock resistance is one of basis of shock damper design. Therefore, the researches on self-shock resistance of ship equipments are full of practical meaning.In this thesis, the shock characteristics of marine supercharged boiler is investigated systematically, respectively by frequency-domain simulation method-dynamic design analysis method (DDAM) and time-domain simulation method. The theories and numerical forecasting methods of marine equipments are major studied, and the marine large equipment shock test inputs are researched as well. This thesis is expected to present systematical numerical methods for engineering application.Firstly, the numerical method is studied for shock resistance in frequency domain of marine equipments by DDAM method. The shock response of supercharged boiler under different work conditions is numerically analyzed by 3D DDAM method. The results concludes the shock resistance and the effect of work condition on shock strength, and the limitations of DDAM method is discussed as well, which present reference for frequency domain analysis of shock resistance. Secondly, the time-domain simulation method is applied to analyze the shock resistance of marine supercharged boiler. Taking the Germany military standard as calculation basis, the basic theory of time domain simulation method and numerical experiment method are given in the thesis. The working stress loading method of different work conditions is discussed in order to solve the transient impact response problems of structure with working stress as quickly as possible within the engineering accuracy. The shock resistance of different directions is analyzed. The effect of work conditions on shock strength is studied in detail. The work is expected to present numerical calculation method for time domain simulation method of marine equipments.Thirdly, the numerical calculation method of equipment under multi-physical fields is researched. Taking the superheater tubes in supercharged boiler as subject investigated, the coupled beam and shell elements are adopted to model the tubes, and the restart technique coupled with submodel technique is applied in order to solve the shock response problem high efficiently and correctly. Then the shock characteristics of superheater tubes from different directions under different directions are concluded.Fourthly, the shock input of shock tests for marine large equipments is studied preliminarily. Equipping the supercharged boiler on the ship structure, series of numerical experiments of underwater explosion are carried through, concluding the impulsive environment characteristics. The corresponding loading equivalent methods are present to give the shock input in shock tests by DDAM method and time domain simulation method respectively.