Accurate Evaluation Method for the Hydraulic Bulge Test


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Optical measuring systems provide much more detail on the deformation of the blank in the bulge test than conventional contact height measuring systems. A significant increase in accuracy of the stress-strain curve can be achieved by fitting the surface to more complicated equations than the traditional spherical surface and by considering the local strain data to approximate the curvature for the midplane. In particular an ellipsoid shape is shown to be very accurate in describing the surface of the blank. Contact height measuring systems provide insufficient data to fit a surface to an ellipsoid shape and to establish local strain data. Pragmatic equations are proposed using the work hardening coefficient from the tensile test to approximate the same accuracy in stress-strain curves as obtained by optical measuring systems using the before mentioned evaluation method.



Key Engineering Materials (Volumes 554-557)

Edited by:

Ricardo Alves de Sousa and Robertt Valente




J. Mulder et al., "Accurate Evaluation Method for the Hydraulic Bulge Test", Key Engineering Materials, Vols. 554-557, pp. 33-40, 2013

Online since:

June 2013




[1] R. Hill, A theory of the plastic bulging of a metal diaphragm by lateral pressure, Philosophical Magazine 41 (1950) 1133-1142.

[2] R.F. Young, J.E. Bird, J.L. Duncan, An automated hydraulic bulge tester, Journal of Applied Metalworking 2 (1981) 11-18.


[3] S. Keller, W. Hotz, H. Friebe, Yield curve determination using the bulge test combined with optical measurement, Proceedings of the IDDRG Conference (2009) 319-330.

[4] J. Mulder, H. Vegter, H. Aretz, A.H. van den Boogaard, Accurate determination of flow curves using the bulge test with optical measuring systems, In preparation (2013).


[5] M. Vucetic, A. Bouguecha, I. Peshekhodov, T. Götze, T. Huinink, H. Friebe, T. Möller, B-A. Behrens, Numerical validation of analytical biaxial true stress - true strain curves from the bulge test, Proceedings of the 8th NUMISHEET Conference (2011).


[6] D.M. Woo, The analysis of axisymmetric forming of sheet metal and the hydrostatic bulging process, International Journal of Mechanical Science 6 (1964) 303-317.


[7] P. Peters, C. Leppin, P. Hora, Method for the evaluation of the hydraulic bulge test, Proceedings of the IDDRG Conference (2011) 9 pages, not numbered.