Research On The Transient Statistical Energy Method Of High Frequency Shock Environment Of Submarine Structure

Shock environment is a measure of the ship's shock resistance,also an important indicator for assessing the ship survivability,and it's self-evident to forecast shock environment for the significance of ship design and shipboard equipment shock performance evaluation.The shock response spectrum is the most common form to describe the shock environment.However,due to the limitations of the shock environment prediction method,the high-frequency prediction of the shock response spectrum can not be well solved.Therefore,based on the forecasting of high-frequency shock environment,combined with the transient statistical energy method applied to solve the dynamic response of high-frequency complex structures in this paper,it solves the problem of high-frequency shock environment prediction from the method and engineering application,and carries out fast prediction theory and experimental research of high frequency shock environment Based on transient statistical energy method.Firstly,this paper analyzes the whole flow path of theoretical solution of the energy envelope of the double-coupled subsystem under the single stimulus by using the transient statistical energy method to solve the equilibrium equation,then solves the theoretical solution of energy envelope of the multi-coupled subsystem structure under the single stimulus,that is,which is solved by using transient statistical energy method theoretically.Subsystem energy envelope theoretical solution is used to calculate the acceleration-time curve corresponding to the analysis frequency,and the acceleration of each analysis frequency is superposed to estimate the actual acceleration time history curve of the subsystem.Based on this,the submarine acceleration shock response spectrum is predicted,making forecasting speed greatly increased.Second,test the loss factor of subsystem.The structure of the submarine is simplified and the test model is determined appropriately.The scheme design of the test point and the excitation point is carried out and the inner loss factor and coupling loss factor of the typical subsystem are tested.According to the experimental theory of the transient attenuation method based on Hilbert transform and transient statistical energy with wave method,the experimental data are analyzed and processed respectively.Finally,two kinds of parameters of typical subsystems of submarine are obtained and analyzed briefly.Third,the method of transient energy statistical energy is used to predict the effectiveness of shock response spectrum is verified.The shock response spectrum acquired by the test method is compared with that obtained by the virtual mode synthesis method and the transient statistical energy method used in this paper respectively.The results show that the shock response spectrum obtained by transient statistical energy method and that acquired by the experiment agree well with each other in 100-1000 Hz.The effectiveness of this method in predicting shock environment in the high frequency range is verified.Finally,the shock environment forecast of high-frequency for the multi-subsystem submarine section is stated and the influencing factors of the shock environment are analyzed.The shock response obtained by vitual mode synthesis is compared with that obtained by the transient statistical energy method,and verify the validity of the latter method in predicting the high-frequency shock environment of the multi-subsystem structure.The shock response spectrum influenced by the loss factors,exciting loads and section dimension are analyzed,and the effect of the three on the prediction of high-frequency shock environment is obtained.This paper compares the results of high-frequency shock environment forecasting by experiment,simulation and proposed transient statistical energy method,and verifies the effectiveness of the transient statistical energy method in forecasting high-frequency shock environment,shortens the forecasting time to minute level.The transient statistical energy method provides a new idea for solving the rapid prediction of high frequency impact environment of complex structures such as ships.