Investigation On Hole Making Process And Connection Performance Of CFRP/Aluminum Alloy Laminated Components

Lightweight is the development requirement of modern aerospace technology.Due to the outstanding characteristics of carbon fiber composite material(CFRP)with light weight and high strength,its application in the aerospace field is becoming wider and wider.A large number of CFRP and metal materials have appeared in related products.The key problem facing the aerospace industry is how to ensure the consistency of the stacked structure in the laminated connection area.When making holes in the CFRP / aluminum alloy laminated structure,due to large differences in material properties,defects are easily generated,which affects the quality of the workpiece and thus affects the connection performance of the two materials.Therefore,looking for a high-quality and efficient hole-making process of CFRP / aluminum alloy laminated structure is of great significance for improving the quality of domestic aerospace products.The root cause of the poor hole making quality of the CFRP / aluminum alloy laminated structure lies in the difference in the material removal mechanism of each layer and the complexity of the tool working conditions.In this paper,through experimental analysis,the different process parameters for the CFRP / aluminum alloy laminated structure are studied The influence of quality reveals the formation mechanism of hole-making damage,determines the optimal process parameter range,and explores the influence of process parameters on the tensile properties of the laminated structure.The specific test content and results of this article are as follows:(1)Carried out the research on the cutting force of CFRP / aluminum alloy laminated structure.Aiming at the characteristics of CFRP / aluminum alloy laminated materials,the drilling and milling hole making methods are used,combined with theoretical knowledge to theoretically analyze the change of axial force during drilling.At the same time,the drilling force measurement test during drilling and milling was carried out,the change trend of axial force during the drilling process was analyzed,the influence rule of process parameters on the axial force was discussed,and the stacking sequence was studied.And the correspondence between the processing method and the axial force.The results show that the axial force increases as the spindle speed increases,and decreases as the feed speed increases.The axial force generated by milling and drilling is significantly smaller than the axial force generated by drilling,the maximum axial force when the stacking order is 2A12 / CFRP is greater than the maximum axial force when the stacking order is CFRP / 2A12,and during the hole making process The axial force generated by the tool position feed in the middle of the carbon fiber composite board is the largest.(2)Carried out a research on the cutting temperature of CFRP / aluminum alloy laminated structure.Combined with the drilling temperature theory and the drilling process of laminated materials,the mechanism of cutting heat generation during the hole making process was studied,and the form of cutting heat transfer was analyzed.The temperature change during the hole making process was observed by infrared thermal imaging camera,and the temperature measurement method of CFRP / 2A12 laminated structure was designed.At the same time,the temperature measurement test of the CFRP / aluminum alloy laminated structure was carried out.The change trend of the pore-making temperature of the CFRP / aluminum alloy laminated structure with the technological parameters was studied.The results show that the hole-making temperature increases with the spindle speed,and the hole-milling temperature is significantly lower than the drilling temperature under the same process parameters.(3)Carried out a study on the surface quality of the CFRP / aluminum alloy laminated structure for the hole entrance.The process of chip generation and discharge and its impact on surface creation were analyzed,the chip morphology of the drill hole and the characteristics of the entrance and exit defects of carbon fiber and aluminum alloy were studied,and the comparison test of the hole making quality under different process parameters was carried out.The results show that the stacking order is CFRP / aluminum alloy,which is beneficial to chip breaking.The entrance and exit defects of aluminum alloy are mainly burrs and protrusions,and the surface defects have a clear decreasing trend with the increase of rotation speed.The hole-making defects of carbon fiber composite materials are mainly tears and burrs.There are no obvious defects at the entrance and exit of the interface,and it is not affected by the processing conditions.When the stacking order is CFRP / aluminum alloy,the carbon fiber exit tear can be avoided,and the hole making defect is the smallest when the spindle speed is 5000 r / min.(4)The tensile properties of the CFRP / aluminum alloy laminated structure were developed.Combined with the failure theory of the plate structure,the influence law of the hole-making defects on the damage load of the laminated material is analyzed,and the failure forms and causes of the laminated connector at different plate thicknesses are discussed.Off test.The results show that the carbon fiber tearing defects will reduce the tensile properties of the laminated material,and the small thickness of the aluminum alloy plate will cause the rivet sleeve to fall off,which will cause the connector to fail prematurely.