Research On Eddy Current Response Characteristics Of Plastic And Fatigue Damage In Aluminum Alloy

Based on the advantages of small density,high strength,corrosion resistance,aluminum alloy played an important and irreplaceable role in the fields of aviation,ship,railway,automobile,chemistry and other industrial fields.Eddy current detection technology has the advantages of non-contact,high flexibility,easy to realize automation,without coupling agent,and can work at high temperature.It is widely used in the field of industrial nondestructive testing.However,the related research at home and abroad is mainly focused on the elastic phase of aluminum alloy materials.This paper is based on the eddy current testing technology for aluminum alloy The plasticity and fatigue damage of materials have been studied in depth.In this paper,the relationship between the plastic residual deformation of 7075 aluminum alloy and the relationship between fatigue cycle and eddy current response is studied on the basis of experiment and numerical simulation.The influence of stress ratio,maximum fatigue stress and fatigue cycle number on the eddy current response is obtained,which can be used to evaluate the plastic damage and fatigue damage of aluminum alloy.It provides data and technical support for safe service.Specifically,the work contents and achievements mainly include the following aspects:(1)Through numerical simulation,the modeling,grid division,loading calculation and post-processing of the simulation model have been completed.Finally,the mathematical model of the tensile direction of the aluminum alloy and the relative variation of the eddy current in the direction of the aluminum alloy and the electrical conductivity of the aluminum alloy is obtained.(2)The plastic deformation of the aluminum alloy specimens was introduced by the tensile test.The eddy current response of the deformation specimen was obtained by eddy current testing.The relationship between the plastic strain and the eddy current response of the aluminum alloy was established,and the change of the electrical conductivity and plastic strain of the aluminum alloy was obtained.(3)Through the fatigue test under different stress ratio,different cycle times and different maximum stress conditions,the relationship between the eddy response of aluminum alloy and the change of stress ratio,cycle times and maximum stress is studied.The fatigue characteristic eddy response surface under different stress ratio is set up,and the final taste is tasted.The mathematical model of fatigue cycle number and electrical conductivity of aluminum alloy under fatigue characteristic condition is established.