Numerical simulation of superplastic forming

The numerical simulation of superplastic formed diffusion bonded components using the finite element method has been available to industry for a number of years. However it remains the case that practitioners in the field, that is, those who make the products, generally remain sceptical of the possibilities afforded by the ability to simulate the SPF process. This paper will explain what SPF simulation can provide and illustrate this with a number of applications. Differences between the tradition flow formulation and an improvement known as the incremental flow formulation will be discussed together with a brief mention of constitutive equation considerations. It is reasonably well known that the finite element simulation of superplastic forming (FE/SPF) can provide a history of the forming process including the developing and final distribution of material thickness. However what is less understood is that the method can yield pressure time cycles that attempt to optimise the forming process by controlling some function of the strain rate so that superplastic behaviour is maintained. Finally problems and opportunities relating to the use of FE/SPF simulation are discussed.