Distinguishing crack damage from debonding damage of glass fiber reinforced polymer plate using a piezoelectric transducer based nondestructive testing method

Advances in new applications for composite materials create a difficult environment for an effective nondestructive evaluation as the complexity of the components increases with time. For the first time in this study, a nondestructive testing technique known as the electromechanical impedance (EMI) method is used to identify two different damage types in a composite structure. Since the EMI method is a non-model method that relies on the variations in the impedance signature that is quantified using a statistical method, data alone is insufficient to distinguish between different damage types as any changes in the structure cause the signature to change. A different method of attaching the piezoelectric transducer is combined with an averaging technique to differentiate the crack damage case from a debonding case. The study is concluded by conducting an experiment involving both damage types where the threshold values were defined for a successful damage identification process.