Effect of loading environment on rubber bolster springs used in railway vehicle bogies

The bolster springs investigated have been used in pairs, fitted at an angle to a bolster beam system for bogies of metro railway vehicles. The product has been used for over thirty years, but recently some springs have shown splits and degradations. A finite element analysis was conducted to identify the causes. Three normal road cases (tare, mean, and laden load) and three combined load cases were investigated. A stiffness curve from the finite element model was compared with test results, which showed good agreement. Natural frequencies and mode shapes were analysed. Two potential degradation areas from the combined load cases were located. The critical areas found from the stress analysis were the same as those exhibited on the actual spring components in service. It is shown that the finite element analysis method can pray an important role at the design stage and for failure analysis.