Determination of temperature stresses in CWR based on measured rail surface temperatures

The main aim of conducted research is determination of temperature stresses due to the uneven temperature distribution in CWR. This paper presents a methodology for determination of temperature stresses in CWR based on (1) measurement system developed by the authors for measurement of rail surface temperatures, and (2) coupled transient thermal-stress analysis for simulation of rail temperature field and corresponding stresses. The main advantages of the proposed methodology are high sensitivity to the small temperature variations, taking into account the effect of thermal inertia, as well as measurement of single input parameter - rail surface temperature. The obtained experimental results showed lower rail temperatures in sleeper zones and rail foot along CWR, which emphasize the effect of heat transfer between rail and sleeper, as well as rail foot and ballast. These effects of heat transfer directly influence the decrease of temperature stresses in the mentioned zones of CWR. The maximum values of simulated temperature stresses are up to 16% less in the centre of gravity of railhead, up to 9.8% less in the centre of gravity of rail foot, and up to 0.2% less in the centre of gravity of rail web, compared to the common engineering calculation. In addition, the maximum value of simulated temperature force, based on temperature stresses in the rail cross-section, was up to 5.3% less than the value obtained in the common engineering calculation