電磁超音波探触子を用いたレール軸力の音弾性測定

概要

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Birefringent acoustoelastic stress measurement has been performed on JIS-60 rail samples on the basis of the combination of noncontacting electromagnetic acoustic transducer (EMAT) and the superheterodyne phase-sensitive detector. Slight change of ultrasonic velocities with stresses can be detected using the resonance method for thin samples or using the phase-detection method in case of long propagation paths. Relative accuracy on the order of 10^<-6> is easily available with both approaches. Applied compressive stress up to 76 MPa (about 60 tons) , which well exceeds the buckling load of long rails, is measured using the shear waves propagating normal to the stress axis at three portions of the rail (top-to-bottom, head, and web). The evaluated stress coincides with the stress calculated from the load and the cross-sectional area within a few MPa. Discussions on the effects of liftoff and residual stresses are provided.
一般社団法人日本機械学会の論文
1994-03-25