Use of a tolerance analysis model for damage identification in structures

The paper describes a method for detecting damage in members of a structure from displacement measurements at its nodes. In the context of structural health monitoring, this task is often addressed with model-based methods that compare measurements with values predicted by finite element analysis. In the proposed approach, the underlying model for damage detection is a sensitivity matrix of the same type that is also used in tolerance analysis of mechanical assemblies. The matrix is calculated using the static analogy, a previously proposed tolerance analysis method that has proven particularly useful and straightforward for structures. If statistically abnormal values of the node displacements are detected, their source is localized by a diagnostic test based on the sensitivity matrix. This was validated by means of simulation plans on examples of statically determinate plane trusses. The results help understand how the accuracy of the test depends on the magnitude of the damage relative to measurement errors. Moreover, they suggest that the test can retain an acceptable accuracy even with a significantly reduced subset of measured displacements.