Bombardier have previously supplied bogies for metro trains to a company in Caracas, Venezuela, and have again been approached to supply further new bogies as part of a contract for new metro trains. However, their customer had concerns about the fatigue life of the bogies in the face of increased passenger numbers and a deficient track.

Bombardier instigated a redesign to take this into consideration. The modified design was then presented to Analysis by Firth to perform a finite element analysis.

The bogie model was created using MSC.NASTRAN for Windows software, based on 3-D CAD geometry supplied out of CATIA, using mainly 20 noded hexahedral elements. The final model consisted of 49,491 elements and 310,139 nodes.

The load cases used were entirely of a fatigue nature requiring a bespoke program which was developed to process data at each weld area, calculating its fatigue life according to its classification. These results were used in NASTRAN for Windows to display damage contours. Bombardier have now presented our results to their client who were very pleased with the much improved fatigue life for the bogie.