ENHANCING INDIRECT ELECTROMECHANICAL IMPEDANCE NDE SENSITIVITY USING ELASTIC METAMATERIAL

This paper introduces a novel approach to non-destructive evaluation (NDE) and quality control (QC) of engineered structures by employing an indirectly bonded electromechanical impedance (iEMI) technique with a metamaterial fixture. Traditional NDE methods encounter limitations such as high cost, restricted accessibility, or sensitivity to complex geometries. The iEMI technique offers a cost-effective alternative by utilizing a piezoelectric element attached to a fixture instead of directly to the part, eliminating the need for individual part instrumentation. However, conventional iEMI setups may be affected by fixture dynamics, obscuring the test specimen's impedance signature. To address this challenge, this paper proposes using a metamaterial fixture with broad bandgap properties to prevent wave propagation within specific frequency ranges, accurately reflecting the part's characteristics. The study focuses on developing a chiral metamaterial beam with two-unit cell designs to control mechanical wave propagation, emphasizing bandgap formation within desired frequency ranges. Experimental setup, bandgap analysis, fixture development, and iEMI performance evaluation are detailed, demonstrating the feasibility of the proposed approach. Conclusions offer valuable insights into the effectiveness of metamaterial fixtures in enhancing iEMI sensitivity and accuracy for defect detection in engineered structures.