COMBINED INTEGRAL AND FE ANALYSIS OF BROAD-BAND RANDOM VIBRATION IN STRUCTURAL MEMBERS

The paper addresses a new approach for the description of broad-band r andom vibrations of components in complex structures. Random vibration s at low frequencies are determined by methods of computational struct ural dynamics. Vibrations al high frequencies are described in an inte gral form, i.e. by means of combination of the Bolotin method of integ ral estimates and the methods of high-frequency dynamics. The fuzzy in termediate range between the upper frequency bound of efficient numeri cal computations and the lower bound of the high frequency approach is examined by means of an example. The methodology essentially reduces the computing costs without noticeable loss of information in the high frequency domain. Further, the approach enables one to indicate a fre quency domain wherein the vibration localisation within structural mem bers occurs. The applicability of the concept is demonstrated by compu ting the broad band random vibrations of a thin-walled cover of an eng ine head.