Sina Zamen and Dr. Ehsan Dehghan-Niri receive ASNT Fellowship

Dr. Ehsan Niri and Sina Zamen HeadshotsSina Zamen, Ph.D. Candidate, and Ehsan Dehghan-Niri, Civil Engineering Assistant Professor, were recently awarded one of five $20,000 fellowships from the American Society for Nondestructive Testing (ASNT). Their fellowship proposal, titled “Evaluation of Rolling Contact Fatigue (RCF) cracks on railheads using nonlinear ultrasound in phase-space domain,” will investigate the use of modern ultrasound testing and analysis methods for use in the railroad sector.

Rolling Crack Fatigue (RCF) in the railhead, or top surface of a railway, is caused by the cyclic loading due to train cycles and can cause abrupt failures, as observed in the fatal 1998 Eschede Derailment and the 2000 Hatfield Rail Crash incidents. The North American rail industry spends more than $300M USD annually replacing due to RCF. Non-destructive evaluation (NDE) is essential to maintain the rail systems and prevent failure. Traditional linear ultrasound testing (UT) presents challenges in the evaluation of RCF, including smaller cracks masking out larger, more significant cracks. A more modern approach to testing, non-linear UT, is often too sensitive to source inconsistencies such as temperature changes, loading, nonlinearity, porosity, and microstructure, which makes accurate analysis in the frequency domain difficult.

Zamen and Niri will investigate the use of phase-space domain analysis in the evaluation of RCF, which is commonly used for nonlinear dynamic systems. The duo hypothesizes that different sources of nonlinearity showing the same signature in the frequency domain will show different characteristics in the phase-space domain. 

For more information about this research, please contact Dr. Ehsan Dehghan-Niri by email at

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