On the prediction of plastic instability in metal sheets
Paper in proceedings, 2007

The current report presents some results from a study on the prediction of necking failure in ductile metal sheets. In particular methods for creating Forming Limit Curves (FLCs) are discussed in the present report. Three groups of methods are treated: Experimental methods, Theoretical/analytical methods, and the Finite Element Method (FEM). The various methods are applied to two different materials: An aluminum alloy and a high strength steel. These materials do both exhibit a distinct necking behavior before fracture, and they do both exhibit only a small strain rate dependence. As can be expected, the resulting FLCs from the various experimental, theoretical, and numerical methods show a substantial scatter. The reasons for these deviating results are analyzed, and some conclusions are drawn regarding the applicability of the different methods.

Forming Limit Curve

ductile failure

strain localization


Sheet metal


Kjell Mattiasson

Chalmers, Applied Mechanics, Material and Computational Mechanics

Mats Larsson

Proceedings of NUMIFORM'07, The 9th international conference on numerical methods in industrial forming processes, June 17-21, 2007, Porto, Portugal, AIP Conference proceedings 908

Vol. 1 129-134

Subject Categories

Manufacturing, Surface and Joining Technology

Other Materials Engineering



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