Wiley InterScience Backfile Collection 1832-2000
The calculation of the pressure cycle is of crucial importance for the successful development of a thin sheet superplastic forming process. The pressure cycle must be such that the forming time is minimized while maintaining a strain rate that maximizes the strain-rate sensitivity parameter, in order to reduce the propensity of the material to undergo localized necking. One way of dealing with this problem is to control the pressure by constraining the maximum equivalent strain rate. This paper presents a general numerical algorithm for achieving such control, in conjunction with a finite element analysis of the forming process. Three examples are given of strain-rate controlled pressure cycles for the forming of a plane-strain strip.
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