Identification of internal damage in ballastless tracks based on Gaussian curvature mode shapes

In order to solve existing problems of ballastless tracks, such as various kinds of internal damage and detection difficulties, this paper presents a method based on Gaussian curvature mode shapes. The proposed method has been validated according to relevant numerical simulations and laboratory tests (e.g. those performed for detecting interlayer damage of CRTS II plate-type ballastless tracks), and had led to the following conclusion: if no damage exists in ballastless tracks, the Gaussian curvature mode shapes will be smooth and continuous under different order modes of the track slabs and no obvious peaks will be found. According to the numerical simulation, in vertical and bending vibration modes of damaged track slabs (e.g. the second-, third-, fourth-, ninth- and tenth-order), the Gaussian curvature modes have obvious peaks at damaged locations; and the second-, third- and fourth-order Gaussian curvature modes of track slabs have discontinuity points at damaged locations according to the calculation made in the modal test for the scale model of damaged ballastless tracks. Moreover, the method based on Gaussian curvature mode shapes can be used for detecting and locating internal damage of ballastless tracks accurately.