Transmissibility-based methods for damage identification on a railway bogie frame

The bogie frame is a safety-critical component of modern railway vehicles. Consequently, railway companies periodically inspect the bogie frame to guarantee a timely damage detection. Current inspection strategies could benefit from condition monitoring during the operation using adequate sensor systems and algorithms. However, the application of methods for damage detection using the bogie frame response is still limited. This work aims to identify the sensitivity of two complementary methods based on the transmissibilities – an updated form of the Transmissibility Damage Indicator (TDI) method and the Maximum Occurrences (MO) method – to detect and locate structural damage. This analysis is supported by flexible multibody simulations that provide the nominal and abnormal response of a locomotive in realistic operational conditions. This work first assesses the effect of differences in track inputs on the sensitivity of the TDI method. Both the length of acceleration signals and the number and location of sensors are analysed, from the perspective of the damage detection capacity. The results show that the TDI method successfully detects cracks with a moderate to large dimension, while the MO method identifies the region where those cracks occur. The transmissibility-based methods are a reliable technique that may contribute to enhance the inspection of railway vehicles.