Finite Element Analysis And Experimental Research For Viscous Pressure Forming

Viscous pressure forming(VPF), a new developed sheet flexible-die forming process, has been playing a good application on sheet metal forming in aerospace industry. Because of the coupled deformation between sheet metal and viscous medium, it is necessary to utilize FEM to analyze VPF. However, existing FE methods can not analyze the deformation of viscous media accurately. In this paper, some key techniques of finite element analysis for VPF are analyzed and FEM for VPF is developed. VPF bulge process and VPF deep drawing process are analyzed by using FEM developed in this paper.The mechanical properties of viscous medium are one of main factors in VPF. But few of research works have concentrated on the mechanical properties and material model of viscous medium. The shear creep and recovery tests are carried out for one kind of typical viscous medium to investigate its rheological properties. Experiments results show that viscous medium exhibits obvious visco-elasto-plastic characteristic. Through analyzing experimental results, the visco-elasto-plastic material model for viscous medium is set up. Compared with exiting simplified material model, the visco-elasto-plastic model can reflect the characteristics of viscous medium accurately, which provides academic basis for selecting viscous medium and numerical simulations.Interface viscous adhesive interaction between sheet metal and viscous media is one of main characteristics on which VPF is different from other sheet metal forming processes. It is related to coupled interaction between viscous media flowing under high pressure and sheet metal deformation. Hence it is difficult to analyze the deformation behavior of sheet metal under the interaction of viscous adhesive stress. In this paper, the principle of viscous adhesive stress tensile test is provided. Using the viscous adhesive stress as tensile stress, sheet metal deformation can be measured directly. An experimental setup was designed and manufactured to carry out the viscous adhesive stress tensile test.