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High Speed Rail IDEA Project 47 [Completed (IDEA)]
Application of LAHUT Technology for Wayside Cracked Wheel Detection
| Project Data |
| Funds: |
$100,000 |
| Staff Responsibility: |
Chuck Taylor |
| Effective Date: |
3/4/2004 |
| Completion Date: |
11/15/2005 |
| Fiscal Year: |
2005 |
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This was a contract with AAR's Transportation Technology Center, Inc. (TTCI) to design, develop, and test a prototype system for wayside cracked wheel detection based on a Laser Air-coupled Hybrid Technique (LAHUT). The LAHUT uses laser pulses to excite ultrasonic waves in the object to be tested, e.g., a wheel. Air-coupled capacitive transducers receive the ultrasonic signals subsequently emitted by the test object after the waves have traveled through the area of inspection. The innovative feature of this technique is that no direct contact with the test object (wheel) is required. This enables automated inspection of wheels as trains roll by a wayside inspection station. The system developed in this contract was designed to detect shattered rim cracks. Post-contract developments could include detection of flange stress cracks and tread stress cracks. The investigative approach included the development of system requirements, the design and fabrication of the prototype system, and the test and evaluation of the prototype in the laboratory and in the field. Laboratory tests on wheels with known shattered rim cracks indicated that the system was capable of distinguishing between the non-defective and defective wheels. Field testing was conducted in TTCI’s Precision Test Track using a dedicated test train with wheels containing selected wheel flaws previously characterized using conventional non-destructive testing techniques. Data from the consist testing in the field were not sufficiently accurate to reliably identify wheel cracks. This was due to such factors as instability of the system for wheel tracking and laser beam placement. Development of a viable product will require modifications to better stabilize the system to improve wheel tracking and laser beam delivery. Other modifications required include the capability to detect actual flaw size rather than just whether a flaw exceeds a threshold limit, increasing the maximum inspection speed above the current 5 MPH, and detection of flaws other than shattered rim cracks, e.g., split rim defects and surface cracks on the tread and flange.
The final report for this IDEA project can be found at:
https://www.trb.org/studies/idea/finalreports/highspeedrail/hsr-47final_report.pdf
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