Study On The Force Measurement Of Spherical Bearing Based On A Low Coherence Optical Fiber Sensing Technology

The spherical bearing is the joint part of the bridge beam and the pier body.It is an integral partof the bridge.The spherical bearing can transfer various loads of the bridge superstructure to the lower part of the bridge.With the rapid development of the bridge undertakings in China,the performance requirements of the ball bearing support are becoming more and more strict.The structural health inspection of the vertical bearing capacity of the spherical bearing is a significant problem related to the development of the national economy and the safety of the people.In particular,most of China's railways,bridges,and highway bearings are ball-type bearings.However,most spherical bearings do not have a dynamometric function and can't be used to detect bearing conditions during use.Therefore,monitoring the vertical bearing capacity of spherical bearings has crucial practical engineering significance for the long-term safe operation of the bridge road.In this paper,a new detection method is proposed for the monitoring of the vertical bearing capacity of the spherical bearing.Based on the Michelson interference principle,an optical fiber low-coherence force sensor designed.The fiber tightly wound around the support and passes through.The vertical bearing capacity of the bearing evaluated by the deformation caused by the vertical load of the ball bearing.The force sensor designed in this paper has the characteristics of high precision,simple operation,low cost and good stability.It is suitable for the monitoring of vertical bearing capacity of spherical bearings.The main content of this article includes:1.A brief introduction to the spherical bearing and the main problems in the health testing of the ball bearing and the necessity of testing the vertical bearing capacity of the spherical bearing.At the same time,the existing measurement on the market Force technology analyzed.2.An optical fiber low coherent force sensor was proposed.The principle of fiber low coherent sensing and the basic principle of white light interferometry for measuring optical fiber deformation introduced systematically.The sensor system used introduced.3.The force analysis of the spherical bearing performed.The QKQZ-I-5000 spherical bearing used in the experiment introduced.At the same time,finite element analysis performed on the static state of the QKQZ-I-5000 ball bearing.Simulations show that under the 5000 KN load,the maximum stress occurs at the upper bearing plate point,which is 74.8MPA,and the maximum vertical deformation is 0.788 mm.4.The experiment of optical fiber white light force sensor carried out.An optical fiber white light force sensor designed,and a ball bearing was loaded with a YAJ-30000 KN press to measure the deformation of the optical fiber wound on the support.The length of the sensing fiber light tightly wound is 7m,and the maximum micro-strain is 149.7?? under 5000 KN load.The maximum error of the experiment is 9.6%,Finally,experimental error analysis performed.