Damage detection and localization based on different types of actuators using the electromechanical impedance method in 3D-printed material

Abstract

The major objective of this work is to comprehend how different actuators react to damage in additively
manufactured (AM) polymer structures. A novel frequency-range selection technique was
suggested based on the maxima of standard deviation of the impedance frequency spectra gathered for the referential and
damage cases. A 3D-printed acrylonitrile butadiene styrene (ABS) plate was used for the
investigation, where two PZT and one macro fiber composite (MFC) actuator were glued to the
surface. Small magnets were used to simulate damage and were positioned at increasing distances
from each transducer as EMI measurements were made using the MFC and 1 PZT. This served
both in studying the transducers’ sensitivity to damage and selecting the proper frequency range
for damage detection utilizing the standard-deviation approach. The EMI-acquired data from the
MFC actuator displays damage-sensitive peaks in a low-frequency band (0 – 58 ), while the
PZT shows a good sensitivity in a higher frequency range (94 kHz – 304 ). In order to evaluate
the PZT and MFC actuators' sensitivity to damage in the 3D-printed ABS plate, impact damage is
also generated in the plate's center. The impedance-based damage indices obtained from different
types of piezoelectric transducers (2 PZTs and 1 MFC) were projected to the same base level and
then fused – for the first time – for impact-damage localization and further added magnetic mass
damage localization. The obtained damage index values of impedance are encouraging for the
evaluation of AM polymer structures with a 4.48 mm positional error from a real location by fusing
data in the different frequency ranges for PZTs and MFC. The damage localization error increases
significantly to the new location beyond the damage sensitivity range of the PZT2 for the added
magnetic mass on the 3D printed structure.