Longitudinal force measurement in continuous welded rail with bi-directional FBG strain sensors. (4th December 2015)

• Record Type: Journal Article
• Authors: Wang, Ping; Xie, Kaize; Shao, Liyang; Yan, Lianshan; Xu, Jingmang; Chen, Rong
• Is Part Of: Smart materials and structures. Volume 25:Number 1(2016:Jan.)
• Publication Date: 2015-12-04
• Subjects: continuous welded rail -- fiber Bragg grating -- longitudinal force -- temperature and strain -- cross-sensitivity -- bi-direction; Smart materials -- Periodicals; Strucural design -- Periodicals; 620.11
• DOI: 10.1088/0964-1726/25/1/015019
• Languages: English
• ISSNs: 0964-1726

Abstract

Abstract: In this work, a new method has been proposed to accurately determine longitudinal force measurement in continuous welded rail (CWR) with bi-directional fiber Bragg grating (B-FBGs) strain sensors (vertically and longitudinally installed according to the axis of rail). The response of B-FBGs has been theoretically analyzed by binding on CWR under different restrained conditions, where the coefficient of strain sensitivity of FBG is calibrated by its temperature sensitivity. Then the proposed sensor structure has been installed at two elaborately selected points on the subgrade on a Chinese high-speed railway in field. The experiment lasts for about 23 h. During the experiment, the rail temperature varied by about 7.8 °C and the differentials of relative value of wavelength change of B-FBGs of two points were 1.7850 × 10 −5 and 1.4969 × 10 −5 . The maximum difference between the experimental and theoretical results is 13.8 kN. The experimental results agree with the theoretical analysis very well. To guarantee the measurement accuracy of over 95%, the ratio of strain sensitivity coefficients of two FBG sensors of B-FBGs structure at one test point shall be within 0.78 ∼ 1.22.