Modeling of the process of superplastic forming of hemispherical shells from blanks of different profiles

Abstract

In the present work, the process of superplastic forming of hemispherical shells from blanks of different profiles on the basis of computer modeling is considered. A relevant task in superplastic forming of shells is to reduce the thickness difference, which will significantly improve the quality of their geometric characteristics with a general reduction in the cost of production. It is shown that the forming of a hemispherical shell from a billet of constant thickness with a fixed flange leads to an inevitable appearance of thickness differenses. It has been shown in a number of works that, in the case of superplastic forming of hemispherical shells from blanks of constant thickness made of titanium alloys, the difference in thickness exceeds 50 %. Various methods have been tried to solve this problem. From the analysis of published works, it follows that the solution to this problem lies in the use of a profiled blank. Traditionally, it is suggested to use a blank with a spherical profile. In the present work, a blank with a conical profile was used, since such a shape of the blank is easier both in manufacture and in calculations compared to a spherical one. The superplastic forming process was simulated using the ANSYS 10ED software package. Using the example of the formation of a hemispherical shell made of titanium alloy Ti-6Al-4V, it was found that the use of a blank with a conical profile makes it possible to reduce the thickness difference down to 7 %.