Numerical analysis of the use of clustering balls in spinning-pressing-forming a curved surface

摘要

In this paper, the spinning-pressing-forming (SPF) method is employed to form a curved surface with smooth curvature. The principle of SPF is presented briefly. Finite element models are built to simulate different forming procedures, including clustering balls spinning after pressing (SAFP), spinning and pressing (SADP), and SPF with different diameters' balls such as big balls (diameter 5mm), mixed balls (diameters 2.5 and 5mm), as well as small balls (diameter 2.5mm). Effects of diameters, loading time, and number of turns are studied through stress and strain, and correlative experiments are done. The conclusions drawn are the following: (1) the average von Mises stress of SAFP is greater and more even than that of SADP, and the average strain of SAFP is higher than that of SADP, indicating that SAFP with greater von Mises stress and higher strain is better for sheet plastic deformed than SADP. (2) Extending spinning time is more effective than extending pressing as revealed by comparison of stress and strain distributions. With increasing number of turns, much stress is released, and plastic strain is improved, which is better for forming. The experimental results are similar to numerical simulation results. Although the three forming processes exhibit differences, the results of thickness thinning have similar trends.