Accuracy issues in modeling superplastic metal forming

K. I. Johnson, M. A. Khaleel, C. A. Lavender, M. T. Smith

Research output: Contribution to conferencePaper

5 Citations (Scopus)


The utility of finite element modeling in optimizing superplastic metal forming is dependent on accurate representation of the material constitutive behavior and the frictional response of the sheet against the die surface. This paper presents work conducted to estimate the level of precision that is necessary in constitutive relations for finite element analysis to accurately predict the deformation history of actual SPF components. Previous work identified errors in SPF testing methods that use short tensile specimens with gauge length-to-width ratios of 2:1 or less. The analysis of the present paper was performed to estimate the error in predicted stress that results from using the short specimens. Stress correction factors were developed and an improved constitutive relation was implemented in the MARC finite element code to simulate the forming of a long, rectangular tray. The coefficient of friction in a Coulomb friction model was adjusted to reproduce the amount of material draw-in observed in the forming experiments. Comparisons between the finite element predictions and the forming experiments are presented.

Original languageEnglish
Number of pages8
Publication statusPublished - 1 Dec 1995
EventProceedings of the 1995 124th TMS Annual Meeting - Las Vegas, NV, USA
Duration: 13 Feb 199516 Feb 1995


OtherProceedings of the 1995 124th TMS Annual Meeting
CityLas Vegas, NV, USA


ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys

Cite this

Johnson, K. I., Khaleel, M. A., Lavender, C. A., & Smith, M. T. (1995). Accuracy issues in modeling superplastic metal forming. 197-204. Paper presented at Proceedings of the 1995 124th TMS Annual Meeting, Las Vegas, NV, USA, .