Manufacturing and testing of a GFRP composite bogie frame with straight side beam members

To replace a traditional steel bogie with a composite one, this study designed and manufactured a composite bogie frame made of glass fiber-reinforced plastics to be applied to the bogie of an urban subway train. To evaluate its structural behavior, the composite bogie frame was tested under critical load conditions encompassing vertical loads and a twisting load. The test revealed that the maximum strain measured under the vertical load corresponded to 16.3% of the failure strain of the GEP224 glass fabric/epoxy sample. According to a durability evaluation using Goodman diagrams, both the measured and the calculated stress data were within the endurance limit. Therefore, the composite bogie frame satisfied the structural safety requirements. The evaluation of the contribution of each load case clearly showed that the vertical and braking loads were the most critical load cases. Adding the braking load cases led to movement of the critical point from the inner joint to the outer joint due to the increased torsion.