Substructuring Model Reduction And Dynamic Response Analysis Of Launch Vehicles

The launch vehicle is an important symbol of the national comprehensive strength,its cost of analysis is extremely high due to its large size and complicated structure.During the structural design stage,many times of analysis and reanalysis are needed to obtain the whole dynamics property and the local characteristics of the launch vehicle,and the modified structure parameter analysis is also necessary.Therefore,the substructuring method is concluded and the classical fixed interface method is modified in this paper.Then,the whole model as well as the local model of the rocket is constructed.Subsequently,the substructure technology is introduced to reduce the models for the subsequent dynamics analysis.And then,the parametric model of the rocket is applied for implementing the automatic substructure analysis.Finally,the substructuring technology based on frequency response function is presented for the dynamic analysis for rockets.The present work has the following advantages: the scale of model analysis can be reduced,the model can be built and computed by parts and the cooperation between different department can be available,the cycle of the structure modification can be cut down,the total model can be reanalyzed efficiently when some variables re changed.The paper is structured as follows:1)The existing dynamic substructuring techniques,especially the fixed-interface component-mode synthesis is reviewed,and the interface reduction is adopted to improve the efficiency of the fixed interface method.2)The domestic and foreign vehicle dynamics modeling methods are investigated to establish the refined finite element model for the carrier rocket.Then,the substructure module in Abaqus is used to get a reduced model which is then analyzed to obtain the rocket's dynamics response,thus improving the efficiency of dynamics analysis.3)Two rocket cabins with bolt connections are modeled.The nonlinear parts of the model are kept original while linear parts are reduced by using super-elements.After that,the reduced model is employed to execute dynamics and nonlinear analysis,which improve the computational efficiency of nonlinear model,successfully.4)The Python language is used to establish the parametric finite element model of the carrier rocket in Abaqus,based on which the auto substructuring analysis is implemented.As a result,the modeling time is decreased and the design cycle is cut down.5)The substructuring techniques based on the frequency response function are studied,and the generalized resistance synthesis is summarized.Then,a frequency based substructuring technique is applied for the frequency response analysis of the carrier rocket with the comprehensive solver in LMS Virtual Lab,successfully.