Identifying and localizing distributed cracks in a complex continuum

A statistical approach for damage detection and localization was recently developed by the author to meet the requirements of an algorithm to be implemented in a wireless sensor microprocessor (smart sensor). To evaluate the performance of the method when applied to real-case situations, the data be collected from a complex continuum exposed to environmental conditions are used. The investigated structure is a masonry wall affected by distributed cracking. Within the framework of the MS thesis by Fabio Beni, the cracks were repaired by mortar injections, and measurements of the structural response were taken before and after the retrofit operation, by applying different excitation methods. The environmental vibration data were elaborated by the author in a previous work, and they showed how the proposed damage index can successfully detect and localize the repaired cracks on the structure. This paper emphasizes how useful information about the damage can be obtained also from the tests with an instrumented hammer.