Distributed fiber optic sensors (DFOS) were used, for the first time, to monitor lateral buckling of a rail under axial loading with different boundary conditions. In the experiments, two types of DFOS systems were used to collect the distributed strain data, and the performance of the two systems was compared. The distributed strain data were used to develop a fitted strain plane at each cross-section along the rail, and axial strain and bending curvature were derived from the fitted strain plane. A data extrapolation method using the distributed curvature data was developed to evaluate the actual boundary conditions at the ends of the rail since they did not match assumed ideal behaviour. The distributed rail deflection along the length of rail was calculated by integrating distributed curvature data and the results were compared with the deflection measured by linear potentiometers (LPs).

分布式光纤传感器 (DFOS) 首次用于监测不同边界条件下轴向载荷下钢轨的横向屈曲。实验中，采用两种DFOS系统采集分布应变数据，并比较两种系统的性能。分布应变数据用于在沿钢轨的每个横截面处开发拟合应变平面，并从拟合应变平面导出轴向应变和弯曲曲率。开发了一种使用分布曲率数据的数据外推方法来评估钢轨末端的实际边界条件，因为它们与假设的理想行为不匹配。