Research On Stamping Forming Charracteristics Of Al/CFRTP/Al Laminates

With the continuous development of advanced manufacturing and science and technology such as transportation and aerospace,people put forward higher requirements for products,such as fuel economy and lightweight structure,reusable and green requirements.Fiber metal laminates are widely used because of their high specific strength and stiffness,excellent fatigue and damage resistance and corrosion resistance,but their hybrid structure and high elasticity of fiber composites seriously affect the formability of FMLs.This paper takes Al/CFRTP/Al laminates as the research object to study the influence of different variables on the forming characteristics of fiber metal laminates after stamping.The specific research contents are as follows:Combined with the experimental environment and the relevant requirements in the process of the experiment,a set of mold which can be used for stamping aluminum plate and thermoplastic carbon fiber prepreg strip is designed.The stamping forming die has the characteristics of high stiffness,high strength and high temperature resistance.By measuring the springback Angle and analyzing the metallographic images of the Ushaped parts produced by different forming paths,it is found that the springback Angle and springback rate of the prefabricated plates are the largest.The carbon fiber in the middle core layer near the inside of the 0° direction occurs compression fracture and forms multiple fiber buckling,while the carbon fiber in the 0° direction near the outside occurs tensile fracture.The springback Angle and springback rate of the mixture were the smallest.The carbon fibers in the direction of 0° both inside and outside the middle core layer were tensile fracture,and the macrodefects such as rich and poor resin zone and uneven thickness distribution were formed.The springback Angle and springback rate of the first forming and then curing are small,and the carbon fibers have tensile fracture in the direction of 0° both inside and outside the middle core layer,and the thickness distribution is uniform without macroscopic defects.A new form of material,fiber lamination,is used to design the structure of the middle layer of fiber metal laminates.The springback Angle of U-shaped parts manufactured by different middle layer structures is measured and metallographic picture is analyzed.It is found that the springback Angle and springback rate of continuous carbon fibers are the largest in the middle layer structure.So the rebound Angle and rebound rate are smaller than continuous carbon fiber.Although the carbon fibers in the 0° direction were tensile fracture in all interlayers,the interlayers of discontinuous carbon fibers showed holes and pores.This shows that the structure design of the middle layer can improve the shape and dimension accuracy of the forming parts of the fiber metal laminates,but it will reduce the forming quality.