Mid-Frequency Vibration Analysis of Systems Containing One Type of Energy Based on a Hybrid Finite Element Formulation 2001-01-1620

A hybrid finite element method (hybrid FEA) for computing mid-frequency vibrations for systems that contain one energy type is presented. In the mid-frequency range a system is comprised of both long and short members. Long members contain several wavelengths and they are modeled by the Energy Finite Element Analysis (EFEA). Short members contain a small number of wavelengths and they are modeled by the Finite Element Analysis (FEA). External excitation can be applied on long and/or on short members. Systems are analyzed by both the hybrid FEA method and an analytical solution in order to validate the hybrid FEA developments. The interaction among long and short members is defined by a set of equations between the EFEA and the FEA primary variables at the interfaces between long and short members. The numerical systems of equations for the long and the short members, and the interface equations are solved simultaneously. Good correlation between analytical and hybrid results is observed for all analyses.