Thickness Distribution of Superplastic Formed Titanium-based Domes

Superelastic forming is an appealing and affordable technique for manufacturing titanium-based structural parts. In this work, circular samples with uniform initial thickness were formed superplastically using finite element modeling (FEM) and the formed domes ore analyzed to investigate their thickness distributions. The results indicate that the dome thickness is not uniform and decreases from the apex to the periphery for each formed dome. The increase of the formed dome height results in the increased thinning of the samples, and the increase of the ratio between the thickness at the dome apex and that at the dome periphery. The predicted thickness distribution based on the Enikeev and Krugloy (E-K) model has a good agreement with the FEM result for the formed domes with a large apex height, while it deviates from the FEM result for the formed domes with a small apex height. A possible reason is the neglecting of the body force from the sample weight in the analytical E-K model. The obtained knowledge will help guide the initial thickness design for the plate samples to realize the expected final thickness distributions.