Research Of Deformation Monitoring For Grain Silo On The Distributed Long-gauge Fiber Bragg Grating Sensing Technique

Silo structure is a special structure used to store materials,which is widely used in metallurgy,building materials,coal,chemical industry,light industry,agriculture and other industries.With the development of economy and the progress of society,the demand for silos in related industries increases strongly,and the size of silos and the tonnage of internal storage materials are also growing.Although scholars at home and abroad have made a thorough study of various structural forms of silo structure,there are still many problems to be solved urgently.Existing silo structures often suffer from a series of structural diseases.Once the silo structures are damaged,it will lead to huge economic losses and casualties.Therefore,it is very urgent to monitor the health of silo structure.But at present there is not much research on the health monitoring of silo structure at home and abroad.In this paper,distributed long-scale fiber grating sensing technology is introduced to achieve the purpose of deformation monitoring of cylindrical silo structure.The main contents and innovations of this paper are as follows:(1)In this paper,the common failure modes and causes of silo structure are analyzed and summarized.For the first time,it is necessary to monitor the health of silo structure.The distributed long-scale fiber Bragg grating sensor is proposed to be used in the research of the health monitoring system of silo structure.At the same time,based on the geometric equation of elastic shell deformation,the radial deformation monitoring algorithm of cylindrical silo structure based on distributed long-scale fiber grating sensor is deduced by using finite difference theory.(2)The validity and error of the proposed algorithm are evaluated in several dimensions by using the finite element simulation software ABAQUS,which verifies the feasibility of the deformation monitoring algorithm.The deformation monitoring algorithm based on geometric equation of elastic shell deformation is compared with that based on circular curved beam model.The advantages of the algorithm based on elastic shell model in monitoring cylindrical thin shell structures with large diameter-thickness ratio are highlighted.(3)In order to verify the feasibility of the monitoring algorithm in practical application,a multifunctional structural deformation measurement system based on high-precision laser displacement sensor is built.This system has higher measurement accuracy and stability than previous research results.Laser displacement sensor measurement system is mainly used to provide reference for the actual deformation of the structure.Then,a steel silo scale model and a long-scale fiber Bragg grating sensor are used to verify the monitoring accuracy of the deformation algorithm.The final experimental results show that the relative error of radial deflection monitoring is less than 30% and the absolute error is 0.1 mm when 16 fiber Bragg grating sensors are laid transversely.Therefore,the radial deflection monitoring algorithm based on distributed longscale fiber Bragg grating sensing technology can be considered to have better accuracy and can be applied to the deformation monitoring of actual silo structures.