A new strain gauge configuration on the rail web to decouple the wheel–rail lateral contact force from wayside measurement

Abstract

The simultaneous presence of bending moments and torques produced by the lateral and vertical contact forces between the wheel and the rail generates a complex strain state on the rail surface, which makes it difficult to identify the strain signals produced purely from the lateral contact force. In this study, a new strain gauge configuration is proposed to decouple strain signals of the wheel–rail lateral contact force from wayside measurements by analyzing the bending strains on the rail web using a full Wheatstone bridge. For this purpose, a finite element modeling of the wheel–rail contact is performed to analyze the bending strains on the rail web and to optimize two instrumented sections for eight electric resistance strain gauges. Laboratory testing is also used to examine the installation scheme of the strain gauges at the two optimal instrumented sections. A good agreement is observed between the experimental data and the simulation results. Strain signals are evenly distributed for about 10 cm in the middle region between the two optimal instrumented sections and only account for the lateral contact force.