Analysis And Research Of Magnetic-Thermal-Stress Coupling Of Cable Stress Sensor Based On Magneto-elastic Effect

As one of the main transmitting and stressed structural components of the large spanbridge, the state of the steel cable directly affects the health status of the bridge. Compared tothe traditional methods of the cable stress measuring, the detection method based onmagneto-elastic effect of cable stress is a new type of cable force measurement method; it hasa lot of merits, such as high measure precision, fast response, and long life and so on. Cablestress sensors based on magneto-elastic effect have been applied to detect the cable stress ofsome practical bridges presently, but the research and development process of this cable stresssensor is based on statistics and analysis of a large number of experimental data, lacking oftheoretically and systematically analysis for magnetization characteristics, stress andtemperature changes, which directly affect the stress detecting process of the steel cablesensor.Making the energy balance of the magnetization process and the main factors, includingmagnetization properties and changing of stress and temperature as the entry point of theresearch, the multi-field coupling model of the cable stress sensor based on magneto-elasticeffect is constructed by analyzing the magneto-thermal model firstly and then magneto-elasticmodel later. Since the theoretical model is a high-order, multivariable and nonlinearmathematical equation, so the successive iteration approximation is adopted to calculate thenumerical solution of the model. By analysis of the numerical results，the affecting mechanismof excitation magnetic field characteristics, stress and temperature for cable stress measuringhas been illustrated in detail, and according to the result acquired from the model, thereference value of work-point of the sensor, frequency and amplitude of the excitationmagnetic field, operating range of the temperature have been advised successfully.