Ali Chaaba*, Lahbib Bousshine, Mohamed Aboussaleh and El Hassan Boudaia
The Journal of Mechanical Science and Technology, vol. 25, no. 11, pp.2859-2870, 2011

Abstract : Limit analysis approaches are widely used to deal with metalworking processes analysis; however, they are applied only for perfectly plastic materials and recently for isotropic hardening ones excluding any kind of kinematic hardening. In the present work, using Implicit Standard Materials concept, sequential limit analysis approach and the finite element method, our objective consists in extending the limit analysis application for including linear and non linear kinematic strain hardenings. Because this plastic flow rule is non associative, the Implicit Standard Materials concept is adopted as a framework of non standard plasticity modeling. The sequential limit analysis procedure which considers the plastic behavior with non linear kinematic strain hardening as a succession of perfectly plastic behavior with yielding surfaces updated after each sequence of limit analysis and geometry updating is applied. Standard kinematic finite element method together with a regularization approach is used for performing two large compression cases (cold forging) in plane strain and axisymmetric conditions.

Keyword : Limit analysis; Non linear kinematic strain hardening; Implicit standard materials; Mathematical programming; Finite element method