Health and load monitoring in an aluminium plate through guided waves

Guided wave (GW) based Structural Health Monitoring (SHM) systems are widely promoted in literature for their capability in damage and load monitoring, providing benefits in terms of inspection and maintenance/repair operations. The high sensitivity of GWs to both loads and damages, however, alters in a similar way the measurements gathered by piezoelectric (PZT) sensors network, leading to possible false positives. This paper proposes an experimental tests campaign carried out on a piezo-monitored aluminium plate, 360 mm x 500 mm x 2 mm sized, subjected to a tensile load. The plate was loaded under different load levels, each individually, by using an electromechanical test machine, the Zwick/Roell 250, equipped with a 250 kN load cell, and the diagnostic signals dataset was acquired in a specific frequency range. Load effects were thus analysed along different measurement paths in terms of amplitude and velocity variation, also in presence of a simulated damage.