Online Monitoring Of Stress Of Bridge Steel Cable Based On Magnetoelastic Effect And Development Of Reconfigurable System

Due to its excellent tensile properties,high fatigue strength,and strong impact resistance,steel cables are now the major force and force transmitting components in major construction equipment and fields such as bridge construction,cranes,and cable cars.The change in the cable's cable force is an important indicator of the health of the steel cable structure.The steel cable has long been subject to failure due to corrosion,overload,fatigue and other factors in the natural environment,resulting in major accidents and losses.The cable force testing technology based on the magneto-elastic effect is a new type of non-destructive testing technology.Because of its advantages such as simple structure,low cost,and high measurement accuracy,it has been widely used in the monitoring of cable forces at home and abroad.However,due to the special structure of the existing magneto-elastic force sensor,it is difficult to install,maintain and calibrate the steel cable stress measurement,which is not conducive to the cable force monitoring of the steel cable in service.Therefore,the original magneto-elastic sensor is optimized and the new sensor structure has important practical significance and practical value.In this paper,based on a review of the shortages of the existing magneto-elastic sensors,finite element simulations were performed for telescopic magneto-elastic sensors.The optimized design work was performed on the structure of bypass magneto-elastic sensors,and a flexible magneto-elastic sensor was proposed.Enclosed magneto-elastic sensors,enveloping magneto-elastic sensors,placed magneto-elastic sensors,and mutual magneto-elastic sensors,and many other new sensor structures,built a hardware and software platform for cable force measurement,and programmed signal detection.The process was performed and cable rope force measurement tests were conducted on a variety of magneto-elastic sensors.The main research content is as follows:(1)Based on the magnetic and magnetic characteristics of the steel cable,the mechanism of the magnet cable effect of the steel cable is elucidated from the energy point of view.Based on the mathematical model of the cable force measured by the magnetoelastic method,the corresponding cable force calculation formula is deduced.(2)Based on the mathematical model of the measurement of the cable force by the magneto-elastic method,a finite element simulation model of the sleeve-type magneto-elastic sensor was established.The distribution of the magnetic induction intensity in the steel cable was analyzed,and the relationship between the stress of the steel cable and its permeability was obtained.alternative relation.(3)Developed five new reconfigurable magneto-elastic sensors,including a flexible magneto-elastic sensor,a semi-enveloping magneto-elastic sensor,an enveloping magneto-elastic sensor,a placement magneto-elastic sensor,and a mutual magneto-elastic sensor.Problems with installation and maintenance of telescopic magneto-elastic sensors has been solved.The hardware system of the magneto-elastic force measurement system was set up to realize the generation of excitation signals and the pre-amplification and filter processing of power and detection signals.Based on Lab VIEW developed the corresponding data acquisition software to complete the detection signal acquisition and preprocessing operations.Based on MATLAB,a data post-processing program was written to realize digital filtering,zero-line adjustment and numerical integration of detection signals.(4)Based on different excitation structures,the cable force measurement comparison tests were performed on the above five magneto-elastic sensors to verify the feasibility of the new sensor to achieve cable force measurement.The experimental results show that the five new magneto-elastic sensors designed have higher linearity and can adapt to the cable force measurement.Among them,semi-enveloping and enveloping magneto-elastic sensors have better sensitivity and better measurement performance than by-pass magneto-elastic sensors.