Experimental Study On Corrosion Fatigue Damage Detection Of High Strength Steel Wire Based On Metal Magnetic Memory

As the main tensile component of cable-stayed bridge,suspension bridge and other tied arch bridge,the corrosion defects and fatigue load during service have a serious impact on the service life of bridge cables.Metal magnetic memory detection technology,as a new method in the field of green nondestructive testing,is essentially a magnetic detection technology based on the relationship between magnetic signal changes.Its spontaneous magnetic leakage signals are caused by changes in the signal characteristics due to the change of its microstructure,and there is a huge correlation between such signals and material damage.In order to further explore the change mechanism of magnetic memory signal of high-strength steel wire in bridge cable body under corrosion fatigue coupling,magnetic memory signal detection test platform designed by ourselves was used to collect magnetic signal distribution of high-strength steel wire under different damage states.The main contents and conclusions of this study are as follows:(1)The change rule of magnetic memory signal under the action of single factor of corrosion and stress was explored,and then pre-corrosion-fatigue and pre-fatiguecorrosion interaction tests were carried out,and finally corrosion and fatigue alternating interaction tests were carried out,specifically in two forms: pre-corrosion-fatiguecorrosion and pre-fatigue-corrosion-fatigue.(2)It is found that with the increase of corrosion time,the abnormal magnetic signal caused by corrosion defects becomes more obvious;With the increase of fatigue loading times,the magnetic memory signal of lossless steel wire increases first and then stabilizes.(3)The alternating stress field applied after pre-corrosion will weaken the magnetic signal caused by corrosion defects,and then the peak value of magnetic signal caused by corrosion defects will continue to increase;The application of the alternating stress field of pre-fatigue will strengthen the magnetic field and cause corrosion,and the peak value of magnetic signal increases compared with that of a single corrosion factor.When the fatigue load is applied again,the signal weakening at the corrosion defect will increase.The results show that the abnormal magnetic signals caused by early corrosion can be masked by fatigue,and the single corrosion factor cannot be used as the only damage index in the actual magnetic memory signal detection of bridge cables.It is necessary to consider the corrosion fatigue coupling effect comprehensively to verify the damage judgment basis of high strength steel wire under the corrosion fatigue coupling effect.