| Most of the structures are working under the action of fatigue cyclic loading,and the fatigue fracture is one of the main forms of structural failure.6061 aluminum alloy is widely used in automotive,aerospace and other fields because of its high specific strength and low specific density and excellent welding properties.It has great theoretical significance and engineering application value to study the variation characteristics of aluminum material and its application in the study of fatigue life by finite element method.The study on fatigue damage mechanism was conducted based on aluminium sheet metal AL6061 with FEM defects analysis.The main works were as follows.(1)Mechanical properties and fracture morphology of AL6061 aluminum alloy were obtained by tensile test.Through the fatigue test,fracture load of the samples with about 20000 cycles was 4300 N.The fatigue test of different cycles with 4000、8000、12000、16000 and fracture were implemented on MTS fatigue machine.Then,these samples were put into CT scanning system for nondestructive testing to obtain the damage defects data.The interior damage distribution and evolution characteristics was analyzed through VG Studio software.It is found that,with the increase of the number of fatigue cycles,the elastic modulus were decreased,the porosity and the maximum damage area fraction were increased.The sphericity of the voids was above 60%,the shape was more than like ellipse.The pore size increased with the increase of the fatigue cycles.(2)The distribution and evolution law of the defects were obtained by the method of three-dimensional reconstruction of CT scanning data in Deigo algorithm for higher accuracy.Compared with VG Studio results,the results from Deigo algorithm had higher accuracy,which illustrated the advantages of Deigo algorithm in 3D reconstruction and defects analysis.(3)The finite element mesh model was generated by MIMICS,and imported into ABAQUS to analyse the changing law of the elastic modulus and strain energy by the method of elastic-plastic.The experimental Young’s modulus was consistent with the trend of effective elastic modulus,which indicated that the simulation method can meet the requirements of fatigue damage analysis. |
PDF Full Text Request