| The development of industrialization has made the current environmental pressure and the energy crisis increasingly severe in our country.Lightweight technology has become one of the important means to promote the sustained and healthy development of industrialization.In recent years,Lightweight materials such as aluminum alloys have led to the upsurge of ‘aluminum substitute steel’ in industry,and it is widely used in the automotive,chemical,and construction industries.With the development of material science,CFRP have emerged from the industrial development with its advantages of light weight,high strength,and strong fatigue performance,which have promoted the development of industrial lightweight reform and become the dominant material in aerospace,automobiles,shipbuilding and other fields.Under the coexistence of a variety of lightweight materials,there will be a problem of safe and reliable connection between CFRP and other traditional lightweight materials.With the introduction of MMD principle,the lightweight design of heterogeneous materials has become a hot topic of research.In this paper,based on the research results of the mechanical connection technology and relevant theoretical methods by domestic and foreign researchers,put forward the method of CFRP/aluminum alloy adhesive-rivet hybrid jointing,The failure loads of CFRP/aluminum alloy heterogeneous materials with adhesive,riveted,and adhesive-riveted joints were analyzed through FEA and tensile shear test,the fatigue damage and fatigue life of the structures were analyzed using the ANSYS n Code software,and the overall performance of the heterogeneous materials was analyzed through comparative analysis.Finally,taking the CFRP/aluminum alloy adhesive-rivet hybrid joints as the research object,the factors influencing the mechanical properties of joints were analyzed and discussed in order to improve the mechanical properties of CFRP/aluminum alloy adhesive-rivet hybrid joints.The main conclusions are as follows:(1)Combining the mechanical properties of CFRP/aluminum alloy adhesive-riveted hybrid joints,riveted,and bonded joints through FEA and experimental method,the results show that the distribution of stress with adhesive-rivet hybrid joints is more even and greatly reduces the stress concentration compare with riveting joints and adhesive joints,which makes the mechanical properties of the overall structure more significant.By comparing the results of the experimental method and FEA method,the feasibility of FEA to analyze the connection of heterogeneous materials was verified.(2)Combining the fatigue damage and fatigue life of CFRP/aluminum alloy bonded joints,riveted joints,and adhesive-rivet hybrid joints under cyclic loading with ANSYS n Code software.The results show that CFRP/aluminum alloy with adhesive-rivet hybrid joints are less damaged than the glued and riveted ones and the overall fatigue life is improved;the overall mechanical performance of the structure is more stable.(3)The glue layer thickness in the range of 0.127mm~0.5mm,the overall equivalent stress,the peeling stress and the shear stress of the glue layer,and the edge shear stress of the CFRP/aluminum alloy adhesive-rivet hybrid joints decreases as the thickness of the glue layer increases,which can prove that the overall mechanical properties of adhesive-rivet hybrid joints is better when the thickness of the glue layer becomes larger.(4)The size of the rivet hole has little effect on the value and distribution of the equivalent stress of the CFRP/aluminum alloy adhesive-rivet hybrid joints;however,it has a great influence on the peel stress and shear stress of the glue layer and the shear stress at the edge of the rivet hole.Combined with the research model of this paper,when the size of rivet hole is 5.2mm,the stress of the glue layer and the rivet hole of the model is the lowest,and the entire model structure is reasonable.(5)The adhesive material has less influence on the overall mechanical properties and the stress at the edge of the rivet of CFRP/aluminum alloy adhesive-rivet joints,but it has influence on the peel stress and shear stress of the adhesive layer,the overall mechanical properties are more stable of the acrylate glue joint with low elasticity modulus.(6)Under the same load,the maximum equivalent stress of the double rivets horizontal layout is reduced by nearly half compared with vertical layout,the peel stress and shear stress of the glue layer are also reduced,which can be benefit to the overall mechanical properties of the entire model. |
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