Mechanical Analysis And Vibration Assisted Optimization Of Aircraft Skin Stretch Forming

Aircraft skin stretch forming is widely used in the production of aircraft.The skin is a key component of the aerodynamic shape of the aircraft.The forming quality of the skin directly affects the aerodynamic performance and service life of the aircraft.This paper takes a model of a skin model of a certain aircraft factory as the research object,mainly as follows:(1)The theory and modeling of the skin shape.Firstly,it introduces the development status of the skin at home and abroad,and clarifies the research direction of this paper.Secondly,according to the previous scholars' research and combined with the specific model tire geometry,it is rationally simplified and the model is established by CATIA software.Finally The finite element model was established by using ABAQUS software for material properties,assembly,load,boundary conditions,contact,and meshing.(2)The trajectory design of the skin stretch forming.Firstly,the role of the skin stretch forming trajectory is outlined;secondly,the principle of the clamp trajectory design is explained;finally,according to the geometric characteristics of the mold,the trajectory of the clamp is derived in the single curvature section and the multiple curvature section respectively.(3)Mechanical analysis of skin stretch forming.According to the derived stretching forming motion trajectory combined with different pre-tensioning and replenishing amount,the finite element simulation of the skin stretching forming was carried out.The amount of rebound is used as a criterion for evaluating the quality of skin forming.According to the analysis,for the geometry of the mold used in this paper,the trajectory of the clamp is designed to have the best overall forming quality of the skin when the pre-stretching amount and the complementary stretching amount are both 1%.(4)Optimization of skin stretch forming.Based on the above-mentioned trajectory with the smallest amount of forming springback,the amount of springback is optimized by the method of vibration assisted forming.Multiple simulation tests were performed using the vibration frequency and amplitude as variables.The results show that for the mold used in this paper,the frequency is 30 Hz and the amplitude is 1.5mm.The lowfrequency vibration reduces the rebound amount from one side to 3.47 mm on the single curvature side,and the optimization degree can reach 54.1%.There is also a 9.3% optimization for the more complex shape of the multi-curvature side.