Reduction effect of cross-sensitivity ratio in instrumented wheelset utilizing shear strains by introducing axially-asymmetric bridge circuit (Investigations by numerical analyses and static load tests)

Instrumented wheelsets are widely used in the railway industry for the purpose of measurement of the wheel-rail interaction forces, which are crucial factors in a running safety assessment. The lateral force, which is the lateral component of the wheel-rail interaction forces, is measured using strains induced by bending deformation of the wheel web in typical configuraions of instrumented wheelset. In addition to the use of bending deformation, the author has proposed a new configuration of instrumented wheelset which usitilizes shear strains of wheel web as a measure of lateral force. In these principles of lateral force measurement using bending or shear strains, the measurement accuracy descreases when a loading point of wheel load, which is the vertical component of wheel-rail interaction forces, is shifted laterally since the wheel load also induces the bending and shear strains. In this research, output characteristics of several types of bridge circuits, which are categolized as “axially-asymmetric bridge circuit,” are investigated for the purpose of reducing the influence of wheel load and improving the measurement accuracy of lateral force. Numerical investigations using a finite element method and experimental investigations are carried out and the results show that the axially-asymmetrization of the bridge circuits is effective to reduce the infuluence of wheel load.