Research On The Critical Technology Of Fiber Placement And Forming Of CFRP Rotary Shell

Carbon Fiber Reinforced Plastics(CFRP)is widely used in various military and civilian fields due to its high specific strength and specific modulus,designable performance and easy integral molding.FDM-based continuous fiber reinforced composite material 3D printing technology can be used for rapid forming of parts with complex geometric shapes.However,because it is based on the principle of plane slicing,the mechanical properties of the fiber cannot be fully utilized in the vertical direction,and it is difficult or impossible to fill the fiber in the thin wall of the revolving shell.Therefore,this paper combines the automatic fiber placement process with 3D printing technology to realize the placement of continuous fibers on the curved surface,and the key technology of CFRP rotary shell molding is studied.The surface of the CFRP revolving shell is layered,and the mathematical model of the offset surface of each layer is established.According to the principle of differential geometry,the expression of geodesic curvature of the curve on the surface is derived.The second-order differential equation of the center angle and height of the geodesic path is established,and the numerical solution of the equation is obtained by the fourth-order Runge-Kutta method.MATLAB is used to simulate the fiber placement process,and the influence of geodesic parameters on the placement line type is analyzed.According to the design principles of composite laminates,the fiber path of each layer of the CFRP revolving shell is defined.The fiber path of each laminate is designed to establish the geometric model of the revolving shell.The mechanical properties of the CFRP revolving shell is analyzed by ABAQUS and compared with the pure resin revolving shell under the same load.The results show that the CFRP revolving shell has a larger elastic modulus of the fiber in the height direction,and the stress and deformation are better than the resin shell under the same compressive load.According to the CFRP rotary shell molding method proposed in this paper,a composite material molding device is designed and built.Completed the research content including the design of dual nozzle structure,dual nozzle control system design and robotic arm motion control.Finally,the device is used to carry out the CFRP rotary shell molding test.The results show that the method of stacking and forming CFRP revolving shells along the curved surface is feasible.