Testing models for superplastic bulge forming of domes

Abstract

The predictions of a new model for the superplastic bulge forming of domes developed by the authors, and of two earlier models, are examined in a study of the variation of dome height with time, the thickness distribution along the dome profile, and the factors influencing the thickness variation. The predictions of the models are compared with experimental measurements made on two aluminium alloys, AA 7475 and Supral 220, and an aluminium bronze, bulged under constant pressure conditions. The recent model shows improved agreement with experiment compared with the two earlier models. It has been shown that the strain rate sensitivity parameter m plays a large part in determining the thickness distribution, while the height of a dome is also important. MST /1145. © 1990 The Institute of Metals.