A dual Craig-Bampton method for dynamic substructuring

A novel component mode synthesis method for dynamic analysis of structures is presented. It is based on free interface vibration modes and residual flexibility components. Although the ingredients are the same as in previously published procedures (e.g. MacNeal or Rubin), our method is fundamentally different in that it assembles the substructures using interface forces (dual assembly) and enforces only weak interface compatibility. The new formulation is based on a fully consistent reduction approach and the reduced matrices so-obtained are exactly dual to the Craig-Bampton reduced matrices. The new free interface substructuring method proposed here is thus more natural then classical free interface synthesis procedures and leads to simpler reduced matrices. We illustrate the efficiency of the dual Craig-Bampton approach for reducing the dynamical representation on a three-dimensional frame.