Design And Experimental Study On Non-destructive Testing Device For Wire Rope Based On Double-level Permanent Magnet Excitation

At present,wire rope is widely used in various fields of production and life.The service performance of steel wire rope directly affects the safety of use.Therefore,it is necessary to accurately judge the remaining life of steel wire rope.Because all kinds of damage will be caused during the use of wire rope,which directly affects the service performance of the wire rope.Accurate detection and identification of wire rope damage is the premise of accurately judging the remaining life of wire rope and avoiding safety accidents.With the support of the National Key Reserch and Develop Program,the design and experimental study of the non-destructive testing device for the wire rope based on the new double-level excitation were carried out,aiming to provide an effective new excitation structure and damage signal processing method for the wire rope,and to provide a feasible scheme for the accurate identification and quantitative judgment of the magnetic field leakage signal of wire rope demage.Firstly,based on the characteristics of wire rope structure and main damage modes,combined with magnetic dipole model,the influence of defect characteristics and device parameters on leakage magnetic field signal was analyzed,and the main detection purpose of non-destructive testing device was defined.Secondly,the overall design of the non-destructive testing device for the wire rope ws carried out,the structure of the device was determined,and the double-level excitation structure composed of three groups of permanent magnets was designed;then,the three-dimensional static magnetic field simulation analysis of the double-level excitation structure was carried out with the three-dimensional finite element model of the double-level excitation structure.The influence of the number of permanent magnets and the distance between the poles on the excitation intensity was mastered,what's more,key parameters of the double-level excitation structure was determined.Thirdly,according to the principle of leakage magnetic field detection,the type of leakage magnetic field damage signal detection sensor were selected,and the signal acquisition circuit module of leakage magnetic field of the wire rope was designed and implemented.Aiming at the requirement of locating the damage location in the process of non-destructive testing of the wire rope,the synchronous acquisition program of damage and displacement signal of the wire rope is designed and compiled.Finally,based on the non-destructive testing device for wire rope,a double-level signal migration superposition noise reduction method was proposed,and the damage signal of the broken wire sample was extracted and identified by this method;then,the functional relationship between the number of broken wires and the signal amplitude was obtained.Moreover,based on this functional relationship,the identification test of the number of broken wires in the worn wire rope sample was carried out.The test results show that the device has a certain capacity to identify the number of broken wires.