Abstract:

In order to improve the computational efficiency of the fixed-interface modal synthesis method,first,the characteristic constraint modes are applied to the order reduction of the interface degree of freedom. Next,the static modes are filtrated to reduce the transformation time of interface matrixes of substructures. Then,the mass matrix of system interface is filtrated and the Ritz transform method is employed to obtain the characteristic constraint modes,thus improving the computational efficiency. Finally,the proposed method is used to analyze the vibration of a car body in white in the frequency range from 0 to 200Hz. The results show that the modified modal synthesis method is of high computational efficiency for the vibration analysis of complex structures in low or middle frequency range,with a computation time increasing by 32.4% and a computation error being less than 2%.

Key words: modal synthesis method, vibration, frequency, Ritz transform, filtration