J. Phys. IV France 08 (1998) Pr8-249-Pr8-256
A 2-D non-local analysis of hydroforming for thin sheetsL.P. Mikkelsen1, 2 and V. Tvergaard2
1 Cambridge University, Engineering Department, Trumpington St., Cambridge CB2 1PZ, U.K.
2 Department of Solid Mechanics, Technical University of Denmark, 2800 Lyngby, Denmark
An enhanced membrane theory is used to analyse hydroforming of thin metal sheets. The use of a plane stress or membrane model for such metal forming studies, rather than a full three dimensional numerical analysis, is highly advantageous from the point of view of reducing computer requirements, but the onset and development of localized plastic straining is not realistically predicted. It has been found that a nonlocal formulation of a membrane model, in which a material length is used to represent thickness effects, can give rather accurate predictions of the full 3-D effects. The non-local model implemented here in a hydroforming study is a 2-D version of gradient dependent plasticity theory. The model is used to illustrate the effect of different initial geometries and of different material length parameters.
© EDP Sciences 1998