Technical Reports

Operational Parameters in Acoustic Signature Inspection of Railroad Wheels

  • 01
  • Apr
  • 1980
AUTHOR: D. Dousis, R.D. Finch
KEYWORDS: Railroad Wheels; Acoustic Signature; Inspection Systems; Residual Stress
ABSTRACT: A brief summary is ,given of some prior studies which established the feasibility of using acoustic signatures for inspection of railroad wheels. The purpose of the present work was to elucidate operational parameters which would be of importance for the development of a prototype system. Experimental and theoretical investigations were conducted to obtain more information on the effects on wheel vibrations of geometrical variations, wear, internal stress etc. Hardware improvements and interfacing were carried out for a ways ide installation, in addition to software development for real time data acquisition and processing. Field tests were made to evaluate sys tern performance, to permit follow-up on certain wheels and to obtain tape recordings from a sample of axle sets in service. These tape recordings were used to optimize the data processing software and to attempt to correlate identifiable wheel conditions with characteristics of the acoustic signature. The greatest signature differences were obtained when one of a pair of wheels was cracked. Differential wear was found to be a major cause of differences in the signatures of good wheel pairs. It is claimed that the knowledge gained from this study is sufficient to warrant the installation of a prototype system with a reasonable likelihood of success. Another important finding is that the frequencies of certain resonant modes shift slightly with changes in residual stress.