Experimental validation of sheet thickness optimisation for superplastic forming of engineering structures

This paper concentrates on the experimental validation of sheet thickness optimisation in the superplastic forming process. Initially, a procedure based on a proportional control method was proposed for determining the required initial thickness distribution, which led to a satisfactory final component. This was successfully implemented in a finite element simulation using ABAQUS. A series of experiments were conducted to verify the simulation results. A Sn-Pb (tin-lead) eutectic alloy was adopted as the forming material, and the sheet was inflated into a dome shape die cavity-forming rig, which was driven by mains pressure hot water. Two kinds of sheet thickness profiles, a simple 2mm thick sheet and a thickness modified sheet (designed to give a final dome thickness of 1mm) were used in the forming. Good agreement was observed between experimentation and simulation.