A Finite Element Model Updating Method Considering Environmental Impacts

Many researchers have observed a strong correlation between variation in structural modal properties and environmental change especially temperature fluctuation. The environmental variability of modal properties might cause uncertainties in modal properties identification. Therefore in vibration-based damage detection field, a practical issue is to discriminate temperature-induced changes in modal properties from those caused by structural damage. Currently, several techniques have been developed to help eliminate the temperature influence, such as using a linear filter to separate the temperature effects. Meanwhile, detailed studies on the influence from other environmental factors, for instance, boundary condition change, are lacking. This paper proposes a novel finite element (FE) method that can consider temperature and boundary condition change, and brings insight to how environment factors influence structural modal properties and how to consider them in the model updating process. In the proposed method, temperature and boundary condition information is incorporated into stiffness formulation of the FE model. A numerical example of damage detection on a pedestrian bridge with several damage scenarios combined with environmental variation is presented to demonstrate the effectiveness of the proposed method. Also, the sensitivity range of each updating parameter is discussed in details.