PSI - Issue 64

Rui-Xin Jia et al. / Procedia Structural Integrity 64 (2024) 799–806 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

806

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shell increases, the energy of the guided wave received at the end face decreases under the same tension.

(a) 60mm-0kN

(d) 60mm-100kN

(c) 75mm-0kN

(d) 75mm-100kN

Fig. 12 Time-frequency diagrams for 60mm and 75mm outsourcing thicknesses

6. Conclusion This paper combines the ultrasonic guided wave technology and acoustic elasticity theory for the effective prestressing detection of rebar, and the main conclusions of this paper are as follows. The flight time of the first wave of the rebar under the excitation of different frequency signals shows a gradual decrease with the increase of the tension force. The first wave speed of the rebar guided wave decreases with the increase of the excitation frequency, which is consistent with the theoretical dispersion curve law; the error between the theoretical wave speed and the results measured in the test is 3%. With the increase of the excitation power, the amplitude of the guided wave in the time domain and frequency domain gradually increases, while the waveform does not change, so the influence of the excitation power can be ignored in the test. The law between the first wave speed and the equivalent tension force after the rebar is covered with mortar is consistent with that of bare rebar, but the energy and so on are significantly decreased compared with that of bare rebar. Acknowledgements The authors gratefully acknowledge the financial support provided by the Incubation Project of Chongqing Research Institute of Beijing University of Technology. References Tao, Y. W. (2012). Common disease and controlling measures of prestressed continuous rigid frame bridge. Bridge & Tunnel Engineering, 10: 122 - 126. Ruan, X, Shi X. F., Li X. X. (2012). Failure analysis of tendon breakout on bottom slab of a pre - stressed concrete box gird bridge during construction. Engineering Failure Analysis, 25(10): 291 - 303 ． Chaki, S , Bourse, G. (2009). Guided ultrasonic waves for non - destructive monitoring of the stress levels in prestressed steel strands. Ultrasonics, 49(2): 162 - 171 ． Deng, N. C., Ou, J. P., Zhou, Z., et al. (2007). Application of fiber brag grating sensor to monitor tensile stress in a seven - wire prestressed steel strand. Journal of Harbin Institute of Technology, 10: 1550 - 1553. Krause, T. W., Little, R. W., Barnes, R., et al. (1996). Effect of stress concentration on magnetic flux leakage signals from blind - hole defects in stressed pipeline steel. Research in Nondestructive Evaluation, 8(2): 83 - 100. Zhong, J. W., Li X. X., Wang, Z. Z. ( 2009). Study of Application of Fiber Bragg Grating Technique to Bridge Testing. Bridge Construction, S2 ： 8488. Zhong, J. W., Wang, B, Wang, X, et al. ( 2019) Research of Bridge Intelligent Inspection Technology and Application. Bridge Construction, 49, S1:1 - 6 ． Chen, P., He, X., Wang, X. (2021). Ultrasonic Measurement of Axial Stress Using High - Frequency Cylindrical Guided Wave. IEEE Sens. J., 21, 6691–6697. Zhu, S. Y., Xu, X. (2022). Axial Stress Measurement of steel tube using ultrasonic guide wave. Sensor, 22(9), 3111. Lu, Y., Xie, L. Y., Song, G. R., et al. (2022). Detection of Bolt’s Axial Stress Based on Acoustoelastic Effect. Journal of Beijing University of Technology, 48(9) :920 - 926. Datta, D., Kishore, N, (1996). Features of ultrasonic wave propagation to identify defects in composite materials modelled by finite element method. Ndt & E International, 29(4): 213 - 223.