Identifying the Appropriate Frequency Response Function Driving Point of a Car Door Using Finite Element Analysis and Modal Testing

Abstract

Abstract Identifying the appropriate frequency response function (FRF) driving point of complex structures is crucial to experimental modal analysis (EMA), but it is often found to be challenging and problematic. Traditionally, EMA analysts tend to place a reference sensor at several potential driving points and excite the points during testing. However, the approach is time-consuming. The aim of this work is to demonstrate an effective procedure for identifying the appropriate FRF driving point of a complex structure using finite element pre-test analysis and modal testing. The demonstration is performed on a car door structure comprising several geometrically complex structural components. The effective impedance method (EIM) is used to identify thirty potential driving points from the finite element model of the car door. The FRF data of the driving points is derived by using the FRF synthesis method and the derived data is compared with the EMA FRF data for validation purposes. Using EIM, three appropriate driving points covering all the modes required within the frequency of interest that is 0 to 100Hz has been successfully identified. The achievement suggests that the use of the effective impendence method for identifying the appropriate driving points is highly dependent on the accuracy and reliability of the finite element model.