Research on Defect Evaluation Method of Aluminum Plate Based on Frequency-Sweep SH Guided Wave

In this paper, a new defect evaluation method of aluminum plate based on frequency-sweep Shear Horizontal (SH) guided wave is proposed. First, a finite element model for the SH guided wave in aluminum plate is established. Slot defects and through-hole defects are simulated and analyzed. The defect types could be identified according to the shape of the reflection coefficient versus frequency curve. The reflection coefficient of slot defect can be used to quantify random defects by quadratic fitting curve with the defect depth. The minimum value point of the reflection coefficient curve for through holes can be used to quantify the diameter of through-hole, which is 0.42 times of wavelength of the SH guided wave. Then, the feasibility of the evaluation method is verified experimentally. The quantitative error for slot defects does not exceed 10.0%, and the quantitative error for through-hole defects hardly exceeds 5.0%.