Reducing downtime
The structural integrity of wheelsets in rolling stock is of great importance. Axle failure can result in derailment, causing service disruption and great expense for the industry, not to mention injury to passengers. Frequently scheduled inspections throughout the lifetime of the axle are beneficial in order to detect any growing fatigue cracks. However, current inspection systems for solid axles require full disassembly of the axle bogey in order to perform a full inspection.
Objectives
AxleInspect has addressed industry needs by designing a system with:
- a phased array probe to operate both in pulse-echo and pitch-catch inspection modes
- adaptability for different axle geometries and axle box configurations with minimum modification
- ability to record encoded inspection data
- ease of mounting and operation during inspections.
Design considerations
Phased array probe
The phased array probe must meet the following design requirements:
- Adaptable to axle end face diameters from 110mm to 160mm
- Operation in pulse-echo and pitch-catch mode
- Provide beam steering and beam skewing capabilities.
Figures 1 and 2 present the probe performance requirements as well as the beam performance achieved.
Inspection scanner
- Mounted onto a wide range of axles and wheel bearing housings
- Ability to position the probe to end face diameters from 110-165mm
- Perform 360° encoded circumferential scan
- Provide radial movement to position the phased array probe as required.
Figure 3 shows the design concept for the inspection scanner and its main parts.
Achievements
The unique prototype phased array probe has met these requirements, providing:
- excellent beam steering and skewing capabilities
- coverage of the critical areas of the axle
- improved detection capabilities.
The developed inspection solid axle scanner met the requirements for adaptability and can be used for:
- inspection of dismantled wheel sets
- inspection of fully assembled wheel sets.
The complete integrated system provides industry with:
- high accuracy and repeatability of the inspection results
- recordable inspection results
- comparison of the inspection results from different inspection intervals.
Figure 4 shows the scanner and the phased array probe mounted on a full length solid axle that artificial defects of various depths have been introduced at different distances from the end face.
Figure 4 also presents the phased array data acquired by system that demonstrates all the introduced defects have been detected with high accuracy.
Commercial application
The system will be developed for commercial application. This next phase will involve:
- full automation of the inspection scanner
- development of software comprising the scanner motion control and phased array data acquisition and analysis
- full validation of the system using relevant railway inspection standards.
The AxleInspect project was a collaboration between: TWI’s NDT Validation Centre, Balfour Beatty Rail, Vermon Danobat Railway Systems, IDEKO, Pheonix Inspection Systems Ltd and West Pomeranian University of Technology.
The research leading to these results has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under Grant agreement number 286573.
For more information: www.axleinspect.euor please email contactus@twi.co.uk