Modified relative arrival time technique for sizing inclined cracks

• A novel method is proposed for estimating length of inclined cracks.
• The proposed method uses ultrasonic B-scan signals.
• The proposed method is based on the times of arrival of the tip and corner echoes.
• The proposed method estimates the crack size as well as its inclination angle.

In this paper, a modified relative time technique is proposed for estimating the length and the orientation of inclined cracks using ultrasonic B-scan signals. The proposed technique utilizes the relative position of the tip diffraction echo to the corner reflection echo in an ultrasonic B-scan image to estimate the crack length and the crack inclination angle. Both finite element simulated signals and experimental signals, which are obtained from a specimen with a 3 mm crack with different inclination angles, are used to evaluate the estimation error of the proposed technique. The results show that the proposed technique overcomes the shortcoming of the conventional relative arrival time technique in sizing inclined cracks.