Thickness-profiling of initial blank for superplastic forming of uniformly thick domes

Abstract

Superplastically formed hemispheres invariably produces thickness variations showing lowest thickness at pole, increasing gradually to a maximum at the equator. The inevitable thickness variations are attributed to the different stress conditions, i.e. balanced biaxial at the pole and plane strain at the equator. In a previously published paper the author published the method of simulation of such thickness variations. In the present paper, an approach of reverse simulation of that has been described through which a thickness profile is created in the initial blank such that the hemisphere formed by gas pressure blow forming technique develops a near uniform thickness profile. The theoretical approach of creating a thickness profile in the initial blank for achieving a uniformly thick dome was validated by blowing a profiled blank to a dome of nearly uniform thickness profile.