Flexibility Curvature Eigenvalue Method for Debonding Damage Identification of Unit Slab Track

In order to identify and locate the debondingdamage on the bottom of the CRTS Ⅲ ballastless trackslab, firstly, the flexibility matrix of the track structure is obtained by its modal analysis, and the flexibility curvature eigenvalue matrixis constructed with the use of the noise reduction data processing and Gaussian curvature. According to the accuracy index that can reflect how irregular protrusions in the non-damage area affect the damage location and the effectiveness index that can identify the damage range, the reasonable density of measuring points is obtained. A variety of damage conditions are established to study the scope of applying the indexes for identification.The results show that the flexible curvature eigenvalue of the track slab with the debonding damage has obvious jump in the damaged area; and its peak value corresponds to the center of the damaged area, which can effectively identify the hidden damage at the bottom of the unit plate track plates of CRTS Ⅰ and type Ⅲ of different material properties. Aiming at the debonding damage of the slab bottom larger than 0.4 m × 0.4 m, the measurement point density of 0.2 m is conducive to reducing the impact of noise on damage location and improving damage scope identification. When the side length of the damaged area at the bottom of the track slab is larger than 0.3 m, the flexibility curvature eigenvalue can accurately identify and locate the damage. The maximum absolute value of the flexibility curvature of the track slab increases with the debonding size, and they have a nearly linear relationship. Thus, with the visual graph of the flexibility curvature eigenvalue, the damage area can be identified. © 2021, Editorial Department of Journal of Southwest Jiaotong University. All right reserved.