Structural Analysis of a Train Gearbox Casing
Due to the complex geometry, the load paths, stresses and displacements of the casings are difficult to predict, even for experienced designers. Wilde used FEA to compare maximum stresses with yield and ultimate tensile stresses, and maximum displacements with available clearances. Peak stresses were assessed for fatigue using a standard Goodman diagram.
Over many years, the client has used FEA as a reliable means of assessing the effectiveness of their designs. They need to ensure not only that the stresses are not high enough to cause failure, but also that the displacements are sufficiently low to avoid interference clashes during operation. Fatigue effects are very important, due to the highly cyclic nature of the loading. The mass of the casing must however be kept to a minimum.
One casing which required analysis was the largest they had designed to date, measuring approximately 1.4m x 1.2m x 0.3m, with a mass of 400kg. The casing was to be cast using SG Iron, and was manufactured in two halves which were bolted together.
April 2000
