Vibration analysis by substructure synthesis method (5th report, A method with identified characteristic matrices)

Abstract

A new substructure synthesis method is proposed. A total structure is divided into some components (substructures). The characteristic matrices (the mass, the damping and the stiffness matrices) of reduced degrees of freedom are identified for each component by a theoretical way or by a vibration test. The identified characteristic matrices of all components are composed to make the reduced equation of motion for the total structure. The three methods are adopted to identify the characteristic matrices of each component, namely Guyan's reduction, identification from the transfer functions and identification from the modal parameters. The vibration of a model structure composed of three triangular plates is calculated by the proposed methods, and the results are compared with the calculated result by direct use of the finite element method. Next, the vibration of an actual crank shaft of an internal combustion engine is calculated by the proposed method, and the result is compared with the experimental result and the calculated result by the component mode synthesis method.