| Wire rope as promotion and loading equipment in the production,transportation and other fields have a wide range of applications,it is very important for the safety performance.Wire rope to work in the long run will produce different degree of fatigue damage,because of the complicated structure and wire rope fatigue damage after no obvious plastic deformation and crack,in the far less than the yield limit and ultimate strength of the material under the condition of sudden rupture,facing the whole device failure,fracture,such as serious threats,industrial production and safety to bring huge hidden danger,therefore,developed a new fatigue damage detection method is imminent,both to ensure that the wire rope before severe fatigue damage can change in time,and can ensure the safety of the equipment operation and does not produce waste of resources,the wire rope fatigue damage detection is of great importance.In this paper,based on the domestic and foreign steel wire rope safety status diagnosis and laboratory,on the basis of existing equipment,based on the parameters of the magnetic properties of test steel wire rope fatigue damage research principles and methods.First according to the laws of the wire rope fatigue damage cause material internal microscopic changes,establish a rope microstructure changes of the relationship between the parameters of the magnetic properties of the model.For wire rope fatigue damage accumulation,crack initiation,crack extension,instantaneous fracture microscopic changes in several stages to make a concrete analysis,combined with fatigue after external metallographic microstructure of wire rope,respectively expounds the fatigue damage and cause of the change of the magnetic properties of steel wire rope.According to the magnetic wire rope mechanical performance,fatigue damage is established with the theory of relationship between magnetic parameters.Secondly,based on the test coil sensor,based on the theory of law of magnetic circuit and sensor design principle,respectively the parameter design of exciter and sensors.To simulate the exciter structure by the finite element simulation,from the three kinds of excitation structure optimal sensor embedded structure are selected,and then the magnetic field analysis,to determine the excitation coil length;Establish a magnetic circuit,determine the design parameters of sleeve and pole;According to the requirements of steel wire rope excitation,the calculation and simulation analysis,the excitation signals are obtained.Sensor design,first of all,to determine the parameters of the detecting coil,then the smaller lift-off value according to the test results more accurate test results to determine the detection coil diameter,finally the integrator circuit design,make the detection device.Finally,by fatigue test and SEM microscopic observation,under different cycle times,get the steel bar inside SEM image and fracture surface SEM image,by analyzing its microstructure change,has been clear about the fatigue crack initiation mechanism,based on the experimental data,the relationship between magnetic parameters of microstructure change model is set up,it is concluded that the micro crack initiation period when the coercive force is larger,the influence of crack extension period when bigger influence on the residual magnetism,etc.Conclusion,microstructure change and the relationship between magnetic parameters as intermediate,wire rope fatigue damage and the relationship between the magnetic parameters of the model.According to the different influence of fatigue damage on a variety of magnetic parameters and using hysteresis loop contains the advantages of multiple magnetic parameters to detect fatigue damage.Using the existing laboratory equipment,combined with homemade detection device,through Lab VIEW design collection procedures,structures,steel wire rope fatigue damage detection platform.Through the Matlab software to piecewise fitting of data,map the different fatigue damage of hysteresis loop,and to test the result. |
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