Development of a non-contact laser speckle imaging system for strain measurements in rails

This paper demonstrated the technical feasibility of non-contact optical sensor for strain measurements which benefits the railway industry in delivering a low-cost, high-resolution and real-time monitoring of structural health of rails and railway components. An optical sensor was developed to measure the surface strain and displacement of a test specimen with a high-roughness surface. The method is based on the movement of laser speckle images (LSI) when the specimen is subjected to the sinusoidal waveform and monotonic loads. A laser beam was directed to illuminate two separated areas through a beam splitter and the surface displacements in these illuminated regions were extracted based on 2D image cross-correlation method to give strains by calibration with results showed that the measurements of laser optical sensor agreed well with extensometer measurements. Although an error of 16% was observed at the initial stage of sinusoidal loading, the maximum error dropped to 3.6% once the specimen was fully gripped. In addition, the maximum strain difference between the measurement of optical sensor and extensometer under linear axial loading was 54, which was acceptable in practical measurement.

Media Info

  • Pagination: 9p. ; PDF
  • Monograph Title: Rail: smart, automated, sustainable: CORE 2018: conference on railway excellence, 30 April-2 May 2018, Sydney, NSW, Australia

Subject/Index Terms

Filing Info

  • Accession Number: 01699298
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ATRI
  • Created Date: Mar 22 2019 2:51PM