单元板式轨道脱空伤损识别的柔度曲率特征值法

为了实现对CRTS Ⅲ板式无砟轨道结构中轨道板板底脱空伤损的识别和定位，首先通过轨道结构模型的模态分析，获取其结构的柔度矩阵，结合高斯曲率和降噪数据处理构建柔度曲率特征值矩阵，利用非伤损区域内反映不规则突起对伤损定位影响的准确性指标和反映识别伤损范围的有效性指标得到合理的测点密度，最后建立多种伤损工况，研究该指标识别的应用范围. 研究结果表明:已脱空轨道板的柔度曲率特征值在伤损区域内存在明显突起，且峰值位置与伤损区域中心吻合，可在无基准参数下有效识别CRTS Ⅰ及CRTS Ⅲ型两种材料性能不同的单元板式轨道板底的隐蔽伤损；针对板底大于0.4 m × 0.4 m的脱空伤损，采用测点密度为0.2 m时有利于降低噪声对伤损定位准确性的影响，提高伤损范围识别的有效性；当轨道板底伤损区域边长大于0.3 m时，可利用柔度曲率特征值进行伤损识别和定位；轨道板柔度曲率最大绝对值随脱空尺寸变大而增加，二者基本呈线性关系，结合柔度曲率特征值的可视化图形可进行伤损面积识别. 

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.