Technology Digests / EMAT NDE for In-Motion Wheel Defect Detection

TD22-021

August 1, 2022
Authors
  • Anish Poudel
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Key Findings

  • Successful testing of both a novel, in-motion, prototype, magnetostrictive EMAT sensor and a liquid, couplant-free EMAT technique was completed to find wheel defects as small as 0.15 inch and up to 0.25 inch deep. To achieve variable depth coverage, different wavelengths can be added to the sensor coil.
  • Four stationary sensors inserted on the field side of the rail are required to provide complete circumferential tread coverage. Each sensor would cover a 2-inch-wide band over about 180 degrees on the wheel.
  • Theoretical achievable inspection speed was calculated at 34-38 mph.

EMAT NDE for In-Motion Wheel Defect Detection

MxV Rail (formerly TTCI) has continued its partnership with Innerspec Technologies, Inc. to develop and test an in-motion electromagnetic acoustic transducer (EMAT) nondestructive evaluation (NDE) technology for detecting internal defects in railroad wheels. Previously, MxV Rail conducted proof-of-concept static testing to demonstrate the capability of EMAT technology to detect internal wheel defects.1 The work performed for the current phase involved a new EMAT sensor and the development of an EMAT technique for conducting in-motion tests using a 12-foot panelized track and wheelsets with known defects. The goal for this phase of testing was to determine the optimal sensor configuration (wavelength and sensor size to improve signal-to-noise ratio) for detecting internal wheel defects by performing the required testing. NDE TECHNIQUE DEVELOPMENT Ultrasonic waves are broadly categorized into bulk and guided waves. The most common techniques for inspecting rail and wheels involve bulk ultrasonic waves where the boundaries of the structure are…