Model Updating: A tool for reliable modelling, design modification and diagnosis

Finite element model updating has become a mature area of research, that is a useful tool in the modelling of structures and is also able to diagnose faults. However applying model updating techniques is not easy, and requires a good physical understanding of the structure. This physical understanding is required to enable parameters to be chosen that correct the underlying modelling errors, and also so that the response is sensitive to these parameters. In this way the number of parameters may be reduced, thereby significantly improving the conditioning of the estimation problem. This paper concentrates on the eigensensitivity approach to model updating, and demonstrates the use of this approach in modelling and also for health monitoring applications. The model of the GARTEUR structure is updated, and the physical meaning of the updated model is tested by using design modifications. Fault detection and location often requires a large number of uncertain parameters since the location of the fault is unknown, resulting in ill-conditioned estimation equations that usually require regularization. Here fault location is used as a parameter and this is demonstrated by locating spacers and cracks in structures.