Numerical Simulation On Anti-shock Analysis Of Large-scale Warship Equipment

The impulsive environment of the ship equipments is very complex. The numerical method to calculate the anti-shock performance of the ship equipments is studied here based on some relevant theories according to different design features. This paper focuses on the computing method and the technique implementation from the basic theories to the numerical simulation. The dynamics response of the ship equipments under the shock loads and the method to check the structural strength are also studied in this paper.Firstly, analyze the design features of the ship equipments and study the modeling techniques including the simplification of the geometrical models, the selection of the element types, the control of the element and the verification of the model, with the non-linearity being considered.Secondly, study the basic theories of the time-domain simulation and the specific implementation of the finite element method. The shock input of the time-domain simulation is researched and the shock input spectrum in frequency domain is converted to the shock wave load in time domain expressed in acceleration. Taking a main turboset as an example, the whole process to simulate its anti-shock performance in time-domain is represented specifically, and the dynamic response of the turboset is also calculated.Thirdly, study the criterions to estimate the weak links and the risky regions. Statistically analyze the structural response of the turboset, estimate the weak regions according to the Pauta criterion and compare this estimated result with that calculated by the frequency calculation method. Comparison indicates that it is feasible to estimate the weak regions of the ship equipment with Pauta criterion when checking the anti-shock performance and the accuracy is satisfying.Fourthly, check the strength of the connecting piece with submodel method. The basic theories of the submodel method are studied and the validity of this method is verified with a main turboset model. As an example, the strength of the joint bolt of this turboset is checked.Lastly, calculate and analyze the anti-shock performance of the equipment by taking the main turboset and the main reducing gear as integrality; compare the result with that calculated when considering the equipments individually.