Author Affiliations
1Hubei Key Laboratory of Advanced Technology of Automotive Components, Wuhan University of Technology, Wuhan, Hubei 430070, China2School of Automotive Engineering, Wuhan University of Technology, Wuhan, Hubei 430070, Chinashow less
Fig. 1. Schematic of defect location detection. (a) Starting point; (b) middle point; (c) terminal point
Fig. 2. Schematic of defect size detection. (a) Detection of defect with diameter Φ1; (b) detection of defect with diameter Φ2
Fig. 3. Schematic of Comsol finite element simulation model
Fig. 4. Interaction process between laser ultrasonic and internal defect. (a) t=2.05 μs; (b) t=2.50 μs; (c) t=3.60 μs; (d) t=4.15 μs; (e) t=4.50 μs; (f) t=5.00 μs
Fig. 5. Schematic of each-mode ultrasonic wave propagation
Fig. 6. Scanning schematic and calculation results when pump laser fixed and probe laser movable. (a) Schematic of scanning form; (b) calculation results of received signals
Fig. 7. Finite element simulation results when pump laser fixed and probe laser movable. (a) B-scan result with defects; (b) B-scan result without defects; (c) difference between B-scan results with and without defects
Fig. 8. Scanning schematic and calculation results of received signals when pump laser and probe laser simultaneously movable. (a) Schematic of scanning form; (b) block 1; (c) block 2; (d) block 3
Fig. 9. Laser ultrasonic detection system. (a) Schematic of system; (b) experimental image of system
Fig. 10. Experiment on shear wave velocity measurement. (a) Experimental diagram; (b) experimental result
Fig. 11. Diagram of 45 steel block to be detected. (a) Three-dimensional diagram; (b) physical diagram
Fig. 12. Scanning schematic of defects detected by laser ultrasonic diffraction bulk wave method
Fig. 13. Experimental results of B-scan for each defect. (a) defect 1; (b) defect 2; (c) defect 3
Fig. 14. Schematic of calculation of defect location and size
Fig. 15. Relative errors from defect diffraction bulk wave detection method
Wave | L wave | S wave | R wave |
---|
Speed /(m·s-1) | 5900 | 3200 | 2900 |
|
Table 1. Sound speed of each-mode ultrasonic wave in 45 steel
Block No. | 1 | 2 | 3 |
---|
h /mm | 10 | 5 | 10 | Φ /mm | 1 | 1 | 2 |
|
Table 2. Parameters of internal defects in 45 steel block
Defect No. | 1 | 2 | 3 |
---|
d /mm | 9.80 | 10.20 | 10.10 | /μs | 6.32 | 3.82 | 6.00 | /μs | 7.26 | 4.66 | 7.80 |
|
Table 3. Arrival time of SS wave and SCS wave at different scanning distances
Defect No. | 1 | 2 | 3 |
---|
l /mm | 12.30 | 12.70 | 12.60 | h /mm | 10.37 | 6.15 | 10.41 | Φ /mm | 1.28 | 1.24 | 2.43 |
|
Table 4. Experimental results from defect diffraction bulk wave detection method