Identification and Synthesis of Components for Vibration Transfer Path Analysis

Sammanfattning: Transmission of structure-borne vibrations in built-up structures, e.g. vehicles such as aircraft, automobiles and trains, is addressed. Methodologies for modeling, analysis, prediction and reduction of vibrations are developed. In particular experimental modeling based on testing and system identification is considered. Special attention is given to identification of physically consistent models. Pertinent substructuring methods that can handle component models based on experimental data are discussed. Furthermore, practical difficulties regarding vibrational testing are addressed. A procedure that is able to extract a substructure model from measurements on a larger dynamical system is formulated. The work also concerns methods for transfer path analysis and vibration control. A critical issue is how to characterize a vibration transmission path. It is shown that different approaches may give deviating results in terms of ranking of dominant paths. Regarding vibration control the problem of optimal placement of sensors is investigated. A method based on Kalman filter theory is developed, whereby the sensor placement problem and prediction of responses inaccessible for direct measurement are simultaneously approached.