Research And Software Development On Two Accurate Dynamic Modeling Method Of Complex Spacecraft Structures

With the development of the engineering technology, and the wide application ofcomputer simulation method in engineering structures, the accuracy of the complexsimulation model draws more attention. In the area of aerospace engineering, theaccurate modeling of complex spacecraft structures has always been a research focus.Finite element method (FEM) is a major tool to build a computational model in practice.It is very important for the designing and controlling of spacecraft to build an accurateFEM model, which could predict the dynamic property and response of the structure.Around the theme of accurate modeling of complex spacecraft structures, two methods(component mode synthesis&model updating) to improve the accuracy of the FEMmethod are studied in this paper.Component mode synthesis (CMS) is a classical dynamic modeling method. Themain idea of CMS method is to separate the complex system into several simplesubsystem, which are analyzed separately, then couple them into a complete system toperform the analysis of the whole system. A new multi-level component mode synthesismethod is introduced based on traditional hybrid interface CMS method in this paper.The presented method makes up for the deficiency the traditional method, which couldonly be applied on two substructures. With idea of multi-level substructuring, thecomplex system could be divided into more subsystems, which simplified the problemand improve the efficiency of the FEM model. A study case is also carried out to provethe mid-frequency calculating performance of the method.Model updating is a popular topic recently. In difference from direct modelingmethods, model updating seeks the improvement of accuracy by updating the FEMmodel with the experimental data. In aerospace engineering, base excitation experimentis a common way to test the spacecraft structure. A model updating method consideringdamping property is introduced in this paper, which updates the FEM model based onvibration test data under base excitation. The main innovation of this paper lies in theidea introducing the damping updating into the scheme, which is very important for theaccurate response prediction of the structure.Simple examples are taken out to prove the effectiveness of the introducedmethods. Based on the examples, the performance and application strategy are studied. The theoretical algorithms are compiled into engineering software with the secondarydevelopment language DMAP and PCL, which could be used to solve practical problem.The designed software is applied to actual spacecraft structures modeling problem,which proved to be useful in engineering. It is a meaningful work for aerospaceengineers to convert the advanced method into engineering applicable tools.