A WAVE BASED METHOD FOR THE MID-FREQUENCY VIBRATION ANALYSIS OF COUPLED LONG AND SHORT WAVELENGTH STRUCTURES

摘要

A wave based method is described for the mid-frequency vibration analysis of a complex structure built-up from a long-wavelength structure and a short-wavelength structure. The long and short wavelength structures have low and high modal densities and modal overlaps respectively. Each substructure is described in terms of global wave functions which are exact solutions of the homogeneous parts of the dynamic equations. Particular solutions of the inhomogeneous dynamic equations are added to these wave functions, so that the displacement approximations satisfy the dynamic equations exactly. Enforcing continuity conditions along the interface hence yields a set of algebraic equations for the vibration response of the built-up structures. Numerical example for plate-frame model is presented. It is illustrated that the new prediction technique yields a high accuracy with a substantially smaller computational effort than the finite element method, so that the new prediction technique can be applied up to much higher frequencies.