Structural dynamic analysis of large complex structures, such as an aircraft, an aerospace structure, or an automobile is a major computational task. Often, the various components of these structures are designed and manufactured in separate facilities for later assembly. Analysis and testing of the components is therefore best carried out independently. The design of individual components must, of course, be based on a knowledge of the expected behavior of the other components as well as of the assembly. Information about the dynamic characteristics must therefore be shared between the sites where the individual components are designed, and efficiency in information sharing is important. A class of structural analysis methods known as component mode synthesis (CMS) methods have been developed for application to such situations. The following steps are involved in an analysis based on the synthesis of component modes
1 Divide the structure into separate components and develop a finite element model for each component. The analytical model will comprise interior degrees of freedom (d.o.f.) along which the component is usually free to undergo displacement and interface d.o.f. along which the component would be connected to other components. As outlined in Section 18.3 the interface degrees must normally include all displacement and displacement derivatives necessary to satisfy the continuity requirements.