title: The Longitudinal Force Measurement of CWR Tracks with Hetero-Cladding FBG Sensors: A Proof of Concept.
abstract: A new method has been proposed to accurately determine longitudinal additional force in continuous welded rail (CWR) on bridges via hetero-cladding fiber Bragg grating (HC-FBG) sensors. The HC-FBG sensor consists of two FBGs written in the same type of fiber but with different cladding diameters. The HC-FBGs have the same temperature sensitivity but different strain sensitivity because of the different areas of the cross section. The differential strain coefficient is defined as the relative wavelength differences of two FBGs with the change of applied longitudinal force. In the verification experiment in the lab, the HC-FBGs were attached on a section of rail model of which the material property is the same as that of rail on line. The temperature and differential strain sensitivity were calibrated using a universal testing machine. As shown by the test results, the linearity between the relative wavelength difference and the longitudinal additional force is greater than 0.9999. The differential strain sensitivity is 4.85 × 10-6/N. Moreover, the relative wavelength difference is not affected by the temperature change. Compared to the theoretical results, the accumulated error is controlled within 5.0%.
authors.affiliation: MOE Key Laboratory of High-Speed Railway Engineering, Southwest Jiaotong University, Chengdu 610031, China. lyshao@home.swjtu.edu.cn.|School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China. lyshao@home.swjtu.edu.cn.
authors.forename: Li-Yang
authors.initials: LY
authors.lastname: Shao
authors.affiliation: School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China. mengzh@my.swjtu.edu.cn.
authors.forename: Meng
authors.initials: M
authors.lastname: Zhang
authors.affiliation: MOE Key Laboratory of High-Speed Railway Engineering, Southwest Jiaotong University, Chengdu 610031, China. kzxie@my.swjtu.edu.cn.
authors.forename: Kaize
authors.initials: K
authors.lastname: Xie
authors.affiliation: School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China. xpzhang@home.swjtu.edu.cn.
authors.forename: Xinpu
authors.initials: X
authors.lastname: Zhang
authors.affiliation: MOE Key Laboratory of High-Speed Railway Engineering, Southwest Jiaotong University, Chengdu 610031, China. wping@home.swjtu.edu.cn.
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.affiliation: School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China. lsyan@home.swjtu.edu.cn.
authors.forename: Lianshan
authors.initials: L
authors.lastname: Yan
keywords: continuous welded rail; hetero-cladding fiber Bragg grating; longitudinal additional force