DYMAT 2009
Volume 2, 2009
DYMAT 2009 - 9th International Conference on the Mechanical and Physical Behaviour of Materials under Dynamic Loading
Page(s) 1595 - 1600
Section Numerical Simulations
Published online 15 September 2009
DYMAT 2009 (2009) 1595-1600
DOI: 10.1051/dymat/2009225

Localization in shell expansion in biaxial loading conditions

J.L. Dequiedt

CEA, DAM, DIF, 91297 Arpajon, France

Published online: 15 September 2009

The development of plastic instabilities in a thin shell loaded in biaxial traction in its tangent plane is difficult to justify when the constitutive material is elasto-plastic with a Von Mises yield surface. The criterion for the activation of bands of localization is not fulfilled except for strongly negative strain hardening parameters (in other words, a strong strain softening effect which is probably never met). On the contrary, the use of a Tresca yield surface leads to bands for perfectly plastic materials. The simulations of plastic instabilities in an expanding hemisphere of tantalum with a Steinberg plasticity model show the same tendencies: the use of a Von Mises yield surface gives no localization whereas the use of a Tresca surface gives a localization pattern which looks like the one observed experimentally.

© EDP Sciences 2009