Elimination of Environmental Influences from Damage-Sensitive Features in a Structural Health Monitoring System

摘要

An attempt is made to eliminate the environmental influences from the modal parameters, the changes of which are used as an indication of damage in structural health monitoring. The technique is based on factor analysis: it is assumed that there exist common factors that have an effect on the features. These effects are subtracted from the observations and the remaining unique factors are used in damage detection. The technique was tested with simulated data and with a structure in the laboratory. The environmental variables need not be measured and the underlying physical quantities need not even be known. The same model can be used for different structures and there can exist several common factors affecting the observations. Limitations of the method are that the relationship between the environmental variables and the features must be linear and that a multivariate feature vector must be used.