Clamping Force Effects on the Performance of Mechanically Attached Piezoelectric Transducers for Impedance-Based NDE
Additional Document Info
Impedance-based non-destructive evaluation (NDE) constitutes a generalization of structural health monitoring (SHM), where comparisons between known-healthy reference structures and potentially-defective structures are used to identify damage. The quantity considered by impedance-based NDE is the electrical impedance of a piezoelectric element bonded to the part under test, which is linked to the dynamic vibrational response of the part under test through electromechanical coupling. In this work, the piezoelectric element is not bonded directly to the part under test, but rather to a c-shaped clamp, which is then mechanically attached to the part under test. Under this attachment condition, the effect of clamping force on the sensitivity of the impedance-based evaluation is investigated for machined steel blocks with varying levels of damage severity. The highest clamping force tested (600lb, 2670N) was the only condition exhibiting increasing damage metric values with increasing damage severity in the parts under test, suggesting that higher clamping force increases sensitivity to damage.