Embedded Sensitivity Functions for Experimentally Diagnosing Vibration Problems and Identifying Nonlinear Models of Automotive Components 2005-01-1502

In the development and manufacture of vehicle components and systems, it is often necessary to quickly identify optimal design modifications for mitigating noise and vibration problems to meet the production schedule. To address this need, experimental techniques for determining the sensitivity of forced vibration response to changes in mass, damping or stiffness properties are of great use. In order to distinguish physical changes in the system from nonlinear input-output distortion, experimental techniques for identifying nonlinear input-output models in mechanical systems are also needed. The use of experimental sensitivity measurements and analyses for studying linear and nonlinear forced vibration data is examined in this work. Embedded sensitivity functions are first used to identify design modifications for reducing a vibration resonant problem. These sensitivity functions are then applied to characterize and identify a nonlinear mechanical system and the accuracy of estimated nonlinear parameters with respect to several factors is examined. A vehicle exhaust system is used to experimentally demonstrate the results achieved using the diagnostic and system identification methods.