Vibration analysis of line-coupled structures using a coupling load decomposition technique

A new substructuring technique is proposed to perform vibration analysis of line-coupled structures. In dividing the whole structure into a master structure and several auxiliary structures, a variational formulation is used to model the master structure, enabling one to introduce the effects of all auxiliary structures by using their compliance characteristics at several observation points along the junction. Continuous functions of the compliance are obtained via a regression analysis. Given the problem of using the compliance inverse to attain a straightforward formulation, a 'Coupling Load Decomposition' technique is proposed since a direct formulation using the compliance inverse is not feasible. By decomposing the interactive load between substructures, relations with displacement decomposition of the master structure can be found. This new formulation permits the direct use of the compliance of the junction, which may be obtained analytically, numerically, or experimentally. Numerical examples using both calculated and experimentally measured compliance data are given. Simulation results are also compared to those obtained experimentally, showing good agreement in low- and medium-frequency ranges.