Modeling Stress Intensity Factor of Rail Steel under Situation of Growing Fatigue Crack—A Novel Technique

Upamanyu Banerjee

Department of Instrumentation and Control Engineering, National Institute of Technology, Tiruchchirappalli, India.

DOI: 10.4236/ojmetal.2012.23011                

Abstract

Simulation of stress intensity factor as function of rolling contact fatigue cracks of railway tracks and the vehicle load is made with the help of COMSOL Multiphysics software. It is found that the critical stress intensity factor i.e. 41.6 MPa. m^1/2 is reached at a stress level of 32 MPa and at the crack size 11.5 × 10^-2 m.Noting the power law variation of acoustic emission count with increase in crack size (analogous to Paris Law), the simulation was further carried out to model the dependence of measured AE count with the stress intensity factor ahead of a growing RCF crack tip. It is demonstrated that AE measurement can be effective to trigger a control loop for avoidance of fatigue failure of railway track. In view of potential difference in the intensity of back scattered light from surface irregularities, a model is developed to find out the threshold intensity of scattered light that insures safety in the railway system against fatigue failure.

Keywords

Stress Intensity Factor; Acoustic Emission, Scattering; Rolling Contact Fatigue; Crack Growth

Conflicts of Interest

The authors declare no conflicts of interest.

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