Research of the wrinkling elimination of stainless steel SUS304 by viscous pressure

Wrinkling is one of the most important factors influencing a forming precision of sheet metal, which brings difficulties to the forming process of sheet metal. In order to eliminate the wrinkling during the forming process, an accurate prediction is necessary. In this paper, the wrinkling elimination process was investigated based on the principle of the Yoshida Buckling Test (YBT) and viscous pressure forming. The experimental device was designed, and evaluation method of the wrinkling elimination rate was presented by the stainless steel SUS304. On this basis, the wrinkling elimination experiment was carried out, the influences of both the viscous medium molecular weight and the tensile state of wrinkle under the viscous pressure on the wrinkling elimination were obtained.

Experimental Research on Static Dent Resistance of Aluminum Alloy Double-Curved Panel

The static dent resistance performance of the aluminum alloy panel formed using viscous pressure forming (VPF) is studied by experimental methods. The successive load is used to cause the aluminum alloy panel dent in the static dent resistance test. The influence of the curvature radius and VPF process parameters on the static dent resistance performance is researched. Results show that the panel with the smaller radius has a larger stiffness and static dent resistance; the adequate drawing depth can optimum the static dent resistance performance of the double-curved panel and the drawbead also can increase the stiffness and static dent resistance.

Application of Viscous Pressure Forming in Aeronautics and Astronautics

Viscous pressure forming (VPF) is a new developed sheet soft-punch forming process in 1900s. The basic principle and characteristics of VPF are described. The applications of VPF technologies of nickel-based super-alloy corrugated thin-walled part, asymmetrical thin-wall part with variable diameter, super-alloy thin-walled part with variable diameters, corrugated thin-walled part with larger diameter and small section are presented. The results show that VPF is suitable for the forming of parts with high strength, low plasticity, super thin-wall and complex shaped.

Research on Formability of Aluminum Alloy Automotive Panels by Using Viscous Pressure Forming

The viscous pressure forming (VPF) was applied to form an automotive aluminum alloy panel in this paper. The formability of the panel was investigated. Further, the springback characteristics of the panel were analyzed. The results show that the viscous medium is helpful to improve the flow of the sheet blank. The positive and negative springback occur for the panel formed by VPF. It is different from the panel formed by rigid punch forming, in which only the positive springback occurs. Furthermore, the springback value of the panel formed by VPF is smaller than the latter.

Research on Formability of Aluminum Alloy 2024 Sheet by Viscous Pressure Forming

Viscous pressure forming(VPF) using a semi-solid, flowable, highly viscous and certain rate sensitive macromolecule polymer as the forming flexible-die is a good forming method for high strength, low plasticity, complex sheet metal parts. In this paper, the bulging process of aluminum alloy 2024 sheet is carried out by combining methods of experiments with numerical simulation. Influences of viscous medium properties on the geometry of bulging specimens, thickness distribution and the pressure field of viscous medium are analyzed, and the limit bulging heights of aluminum alloy 2024 sheets are obtained. The research results show that choosing viscous medium with high rate sensitivity in the forming process can increase the non-uniformity of viscous pressure field, improve the viscous pressure bulging property of aluminum alloy 2024 sheet, and ameliorate the distribution uniformity of wall thickness of bulging specimens.