Detection of Damaged Supports Under Railway Track Using Dynamic Response of a Passing Vehicle

Track is a key component in railway transportation systems. They are usually fixed by fasteners and supported by discrete sleepers, which sit on the ballast. A lot of research has been conducted to check the integrity of the rail track itself, like railway level and alignment; however, limited work has been carried out on the damages of railway supports including loosing and missing fasteners and damaged ballast. In this paper, the support-track-vehicle interaction system is analyzed in which the supports and track are modeled as evenly distributed springs and Euler beam, respectively, and the vehicle is simplified as a spring-mass system. It is found the natural frequencies of the interaction system change periodically with respect to the location of the vehicle, whereas the periodicity is broken when the support is damaged. Then, a detection method is proposed to identify the damaged supports by using the vertical acceleration of the traversing inspection vehicle, which acts as both the "exciter" and "message carrier" of the test. It shows good performance on the detection of damaged supports in both numerical and experimental validations. Moreover, it is more practical than other detection methods in real engineering applications because only one single accelerometer is required.