Research On The Punch-shear Clinching Process For 5182 Aluminium Alloy Sheets

The punch-shear clinching process uses the punching action and plastic deformation of the material to join the sheets.This process has the advantages of simple tool design,high efficiency and the ability to join less plastic materials.However,little research has been carried out into the punch-shear clinching process,which has limited its application.In this paper,we investigated the forming process of 5182 aluminium alloy sheets by punch-shear clinching,and analysed the tool and process parameters that affect the mechanical properties of the joint.The Rousselier constitutive model coupled shear damage was chosen to describe the deformation behaviour of 5182 aluminium alloy.The corresponding material parameters were calibrated by combining with ABAQUS simulation software.The initial void volume fraction f₀ was determined to be 0.005,the critical void volume fraction f_c was determined to be 0.12 and the shear damage factor k was determined to be0.9.The model was then applied into a finite element model of punch-shear clinching and used to analyse the material flow behaviour,damage evolution at the punching surface and stress field changes during the forming process.The results show that the punching action leads to a rapid growth of void in the punching surface of the sheets,the lateral flow of the material under pressure after fracture forms a mechanical lock,and the maximum stress in the formed joint is mainly concentrated in the rounded corners.Afterwards,the effect of punch angle and die clearance on the geometry of the joint was analysed using the finite element method.On the basis of the simulation analysis a die was designed for the punch-shear clinching experiment.The cross section profiles of the joints at different forming stages were obtained and microscopic profiles of shear fracture were observed on the punch-shear surface of the joints.The mechanical properties of the joints at different forming stages were then tested.The results showed that the tensile and shear loads of the joints increased as the forming force increased.The failure mode transitioned from pull-off to neck fracture.At a forming force of 35 k N,the shear and tensile loads of the joints were 2324 N and 883 N respectively.Finally,the effect of the process parameters on the joint performance was analysed experimentally.Under experimental conditions,the forming speed had no significant effect on the joint performance,but was able to significantly improve the joint efficiency.The shear load was greatest at an angle of 90°between the long side of the joint and the shear direction,and decreased as the angle became smaller.5182 sheet was joined to6061 sheet and high strength steel sheet.The shear load and tensile load of the joint were higher when 5182 sheet was used as the lower sheet than when 5182 was used as the upper sheet.When joining sheets with a total thickness of 4mm,the mechanical properties of the joint are better when the thickness of the upper sheet is greater than the thickness of the lower sheet.A sheet thickness configuration of 2.5 mm for the upper sheet and1.5 mm for the lower sheet resulted in the best overall mechanical properties of the joint producted in this experiment,with shear and tensile loads of 3490 N and 1118 N respectively.