Modal based updating for the dynamic behaviour of a car trunk lid

The accuracy of the predicted dynamic behaviour of a structure is highly dependent on the accurate properties used in the analytical model. The predicted results computed from the finite element method used to develop the model are often found not to be in good agreement with the experimental results due to the erroneous assumptions made in the finite element modelling. One way to systematically correct the finite element model is to use model updating methods. The main goal of this study was to systematically improve the predicted dynamic behaviour of a car trunk lid using the modal based updating method. HyperWorks and Leuven Measurement System (LMS) test were used for the finite element modelling and modal testing respectively. In order to evaluate the capability of the modal based updating in improving the finite element model, the natural frequencies and mode shapes computed from the updated finite element model of the trunk lid were compared with the corresponding experimental results. The comparison of the results showed that the total error of 65.48 percent predicted from the initial finite element model of the trunk lid has been successfully reduced to 4.74 percent. In conclusion, modal based updating has been successfully used to reconcile the initial finite element model with the physical model of the trunk lid.