Applying Of Free-Interface Complex Component Mode Synthesis

With the rapid development of modem engineering technology, it is necessary to analyzedynamic characteristic of the large-complicated structure exactly and quickly. Component modesynthesis method is an effective way to deal with such problems. Component mode synthesis methodis based on finite element method. It consists in performing the dynamic analysis of structures bydecomposing the structure into substructures and by projecting the equation of motion of eachsubstructure on a projection basis to obtain the reduced systems of the substructures beforeperforming the substructure coupling to obtain the reduced system of the whole structure. Thismethod can not only improve computational efficiency, but also has high calculation accuracy. Thispaper is based on free-interface component mode synthesis method and studies its basic theory andapplications. The content is listed below:1) Firstly, this paper discussed about the basic idea of the component mode synthesis method,and general steps in constructing a synthesis formulation were summarized.2) A mixed space free-interface complex mode synthesis method was investigated. On this basisanother mixed space free-interface complex mode synthesis method was proposed. The substructureswhich were expressed by physical coordinates were analyzed by the Method of State Space. Thismade the theoretical derivation process easier to understand, and easier to program. The numericalexamples show that the two methods can significantly improve the operation efficiency, and has highcalculation accuracy.3) Mixed space free-interface complex modal synthesis method was applied to the localnonlinear aircraft landing problems. The deduced nonlinear synthesis equation was calculated bysegmented-direct-integration method. Numerical examples show that mixed space free-interfacecomplex modal integrated well in the local nonlinear problems, and greatly reduce the size of theoverall equation, and significantly improve the calculation efficiency.4) An analytical approach for nonlinear vibration of a multi-degree-of-freedom system isproposed using the free-interface modal synthesis method. The dynamic responses of the wholesystem can be calculated by the direct integration. Numerical examples show that the methodproposed has high calculation accuracy and is very effective in improve the calculation efficiency.