Finite Element Model Updating using Rotational Response

Abstract

The Finite Element (FE) models have been used in civil, mechanical and aerospace engineering field for system identification and response simulation under various unexperienced loadings. However, the original FE models are difficult to use directly in simulation because the original FE model is different with the present state of actual structure. Therefore the FE models are updated to minimize the differences with real structure. In the existing FE model updating method, generally translational responses measured by accelerometers have been employed to identify the structural properties and update numerical model controlling parameter. This paper proposes FE model updating method only uses rotational response such as angular velocity measurement because the rotational response is more sensitive to damage than translational response in numerical analysis on simply supported beam. First sensitivity of translational and rotational response is investigated by sensitivity analysis on a numerical simply-supported beam. The FE model updating is carried out for a numerical simply-supported beam using an optimization algorithm which minimizes the gap between responses from the actual structure and the FE model reduce. The used responses in FE model updating are natural frequencies and rotational mode shape obtained from angular velocities measured by gyroscope sensor. The sensitivity analysis shows that rotational responses have higher sensitivity than translational responses to the structural and boundary condition changes. Then, the updated model using existing translational response from the experiment two FE models updated using translational and rotational responses are compared to validate he improvement by proposed FE model updating method. From the experiment, using rotational responses is a good enough in FE model updating compared to existing method, using translational responses.