Automated data-based damage localization under ambient vibration using local modal filters and dynamic strain measurements: Experimental applications

• Unsupervised automated output-only data-based damage localization method.
• Experimental demonstration of the method on small and medium scale laboratory setups.
• Use of cheap piezoelectric patch film sensors for dynamic strain measurements.
• New feature for damage localization with changes of level of excitation.
• Multivariate statistical analysis for automated alarm triggering using control charts.

This paper deals with the experimental application of modal filters for automated damage localization using dynamic strain measurements. Previously developed for damage detection, the extension of modal filtering to damage localization consists in splitting a very large network of dynamic strain sensors into several independent local sensor networks. An efficient signal processing coupled to control charts allows a fully automated data-based damage localization once the modal filters are initialized. The method is tested experimentally on a small clamped-free steel plate and a 3.78 m long steel I-beam, both instrumented with a network of cheap piezoelectric patches to measure the dynamic strains. A removable damage is introduced at different positions by means of a small removable damage device. For both applications, the method can successfully detect and locate all damage cases considered, showing the potentiality of the method for field applications.