Study On Mechanical Properties Of Single Lap Adhesive Bonding Joints Under Tensile Load

Body bonding technology,with the emergence of high-strength structural adhesives in recent years,the bonding is able to provide higher and higher strength,and the use in the body-in-white is more and more extensive.As a kind of joint technology,such as the connection of the structural parts of the vehicle body,the maximum load of the adhesiv directly affects the collision safety performance of the vehicle body.When a certain model uses a large number of bonding joints on the wheel house,if the gap control is not good,the actual gap during production will be too large,which will affect the load of the bonding joint.In this regard,the effect of different adhesive layer thickness?Sheet metal gap?on the strength of the bonded joint is studied.It is expected that the load of the bonded joint will decrease with the increase of the thickness of the adhesive layer,and analysis the single-lap joint can be used instead of the spot welded joint.Firstly,EP 5089 structural adhesive,which is widely used in automobile industry,is selected as the research object,through the Tensile Test,Shear Test,Tapered Double Cantilever Beam?TDCB?and End-Notched Flexure?4-ENF?obtained the EP 5089 structural adhesive material property parameters,and the EP 5089 structural adhesive MAT₁69?*MAT_ARUP_ADHESIVE?material card was established.Secondly,starting from the actual use scenario,considering the large plate gaps that may occur in the production process,a finite element model of single lap joints with different rubber layer thicknesses is constructed based on the cohesion model theory,and selected 0.1 mm,0.2 mm,0.5mm,1.0mm,2.0mm,4.0mm and 8.0mm these 7 different bonding thickness joints are subjected to tensile simulation test.At the same time,the tensile test of the corresponding single-lap joint of the thickness of the rubber layer was carried out,and the mechanical properties of the bonded joint were analyzed according to the relationship between deformation,failure and thickness which occurred during the tensile test.The simulation results are compared with the experimental results.The error analysis results are within a reasonable range.The validity of the model is verified and can be used for the corresponding CAE simulation calculation analysis.The results of simulation and test are analyzed.The results show that with the increase of the thickness of the single lap joint,the strength of the structural joint of EP 5089 shows a gradual decay of the logarithm.The confidence level of this property can be More than 98%,the accuracy of the results was determined.Finally,the required joint strength is determined by a tensile test of the spot welded joint.Analyze the design specification of the spot welding joint.The thickness and length of the bonding joint are affected by two different spot welding widths.The finite element model of the bonded joint is used to simulate and compare the spot welding strength.According to the analysis results,the joint of 12 mm lap width can provide the equivalent strength of the spot weding joint in the thickness of 2mm?Sheet metal gap?,and the joint of 15 mm lap width can provide the equivalent strength of the spot weding joint in the thickness of 3mm?Sheet metal gap?.In practical applications,Single Lap Adhesive Bonding Joint alternative Spot Joint can be considered depending on the form of force applied to the joint and at Body-in-white different location's structures.The research work of the thesis has important guiding significance for realizing the strength that the glue joint can provide under different sheet metal gaps,and whether to choose sealing or spot welding when developing the body-in-white.The finite element model established by the test method to obtain the influence of the bonding thickness on the strength has important engineering application value for the simulation analysis and evaluation of the collision safety performance of the following vehicles.