Title

Damage tracking in variable environmental conditions

Document Type

Conference Proceeding

Date of Original Version

12-1-2006

Abstract

A new method for damage tracking and identification in variable environmental conditions is described. The method is based on dynamical systems perspective on damage evolution, where damage is viewed as evolving in a hierarchical dynamical system with distinct, two time-scales. Fast-time dynamics is related to structural vibrations that can be measured directly. Slow-time dynamics describes damage evolution driven by fast-time variables and causes drifts in structural system parameters. Fast-time vibration measurements are used to develop damage tracking feature vectors based on phase space warping concept. A smooth orthogonal decomposition (SOD) is used to identify linear subspace of the feature space related to the changes in environmental conditions. Damage tracking and identification is performed in a feature subspace that is not sensitive to the changes in environmental conditions. For this the SOD is applied to the feature vectors projected onto this subspace. The method is validated using an experimental system, where a vibrating cantilever beam is subjected to a two-dimensional damage process. The damage is introduced by perturbing the nonlinear potential filed of the beam with a pair of electromagnets. The changing environmental condition is simulated by altering the lighting conditions that affect the optical motion sensor readings. The results show that the damage modes can be separated from the environmental changes.© (2006) by the International Institute of Acoustics & Vibration.

Publication Title

13th International Congress on Sound and Vibration 2006, ICSV 2006

Volume

1

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