Non-contact absolute stress measurement in rail using photoluminescence piezospectroscopy:laboratory and field studies for high-speed rail tracks
A novel non-contact,mobile sensing technique to measure absolute stress in rail using Photoluminescence Piezospectroscopy(PLPS)is presented.PLPS is a vibrational spectroscopy technique for chemical identification and stress measurement by focusing lowpower laser on a substance surface.Thermite welding is a major welding method for continuous welded rail(CRW),which produces iron(Fe)and aluminum oxides(Al2O3)after aluminothermic reaction.PLPS was used as a non-contact stress sensing method since PLPS has an excellent detectability for alpha-phase aluminum oxide(α-Al2O3).Using a portable PLPS system,a prominent α-Al2O3 signal was collected from the bare surface of thermite weld samples.A loading frame test was conducted to determine the piezospectroscopic coefficient of α-Al2O3 in thermite weld.A pulverization method is introduced to determine absolute stress from an existing rail sample.The experimental results show many advantages of this method over traditional methods to measure stress in rail as a mobile sensing method.The PLPS technique was also validated at full-scale high-speed rail tracks managed by Korea Railroad Research Institute(KRRI).The stress time history measured with PLPS was compared with traditional strain gauge measurement.The comparison shows a good agreement for multiple days of field measurement.
continuous welded rail thermite welding absolute stress measurement photoluminescence piezospectroscopy α-Al2O3 non-contact sensing
Hae-Bum Yun
Associate Professor,Department of Civil,Environmental and Construction Engineering,University of Central
国际会议
The 7th World Conference on Structural Control and Monitoring(7WCSCM)(第七届结构控制与监测世界大会)
青岛
英文
1317-1327
2018-07-22（万方平台首次上网日期，不代表论文的发表时间）