| In recent years, the rise of steel wire tire has become a trend in the development of tires manufacturing thanks to its excellent performance in terms of comfort, abrasion proof and high-speed buffer, safe and reliable, etc. As a skeletal material, the steel wire array has a direct impact on load supported and performance of the latter product and has become a compulsory on-line testing in production. The X-ray testing on the final tire can find most defects, however, at early stage, the defective products can be removed in time by the detection of arrangement of wire and cutting splicing after rolling process, which greatly avoid the wastes in large quantity and the large costs of the following processing. Therefore, recently, the research on the wire array detection becomes a hot spot of some international companies and academic institute. Traditional laser detection and X-ray method has been gradually replaced because of their shortcomings, says, harmful rays, large investment, so one of our targets is looking for a new method with safety of low-cost and high sensitivity. But the successful research is rarely reported so far. This dissertation presents a detection method of wire array gap and defects based on electromagnetic detection principle and do some in-depth research on the critical component of the system - sensors by finite element method.The main work of this dissertation can be listed as follows:(1) Present the steel wire gap detection method and sensor's structure. According to the information from the electromagnetic space impacted by the material state change of detection system and physical properties of equipment materials. The sensor is comprised of soft-magnetic core with high permeability and low-power and the winding of the enameled wire. Theoretical analysis shows that the method for industrial inspection is feasible.(2) Establish the analysis model of detection system. First, according to the fundamental characteristics of electromagnetic field, we establish the continuous mathematical model of practical engineering problem based on Maxwell's equations, and then establish the three-dimensional analysis model of system using the method of the equivalent discrete processing based on the finite element method. The electromagnetic parameters of any point in the domain of the field strength, depletion, etc. can be calculated by the corresponding numerical calculations methods, which can solve such a electromagnetic problem of the complex structure is resolved effectively.(3) Optimize the performance of the detection system. The finite element analysis software ANSYS which blends the multi-field environment was used to perform the on-line simulation, optimize the structure and physical parameters of the sensor, and to maximize the sensitivity of the sensor and system performance.(4) Extract the faint signal of detection system. The sensor output signal is weak while the random testing noise generated by outside world and the device itself is very strong. In this dissertation, the phase-locked amplifier circuit is used to detect the weak signal of the three-dimensional magnetic field buried in a large number of non-correlated noise and suppress interference effect at the same time.(5) Analyze various of typical defects in wire array. In industrial production, the shortcomings of steel wire array caused by the shortage of steel root, dislocation, irregular, crack, broken wires, etc., which can occur in the strip plane, and the core axis orthogonal to the vertical plane with the strip level, or the special synthesis of both. In this dissertation, we analyzed the signals in the defective state carefully to provide an effective basis for a comprehensive inspection of the system.The detection method proposed in this dissertation was a useful exploration and attempt for the application of electromagnetic non-destructive testing principles, which has some theoretical value and the prospects on a wide range of industrial applications. |
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