A comparison of the primal and semi-dual variational formats of gradient-extended crystal inelasticity
Artikel i vetenskaplig tidskrift, 2017

In this paper we discuss issues related to the theoretical as well as the computational format of gradient-extended crystal viscoplasticity. The so-called primal format uses the displacements, the slip of each slip system and the dissipative stresses as the primary unknown fields. An alternative format is coined the semi-dual format, which in addition includes energetic microstresses among the primary unknown fields. We compare the primal and semi-dual variational formats in terms of advantages and disadvantages from modeling as well as numerical viewpoints. Finally, we perform a series of representative numerical tests to investigate the rate of convergence with finite element mesh refinement. In particular, it is shown that the commonly adopted microhard boundary condition poses a challenge in the special case that the slip direction is parallel to a grain boundary.

Crystal plasticity

Semi-dual format

Gradient enhanced continuum

Författare

Kristoffer Carlsson

Chalmers, Tillämpad mekanik, Material- och beräkningsmekanik

Kenneth Runesson

Chalmers, Tillämpad mekanik, Material- och beräkningsmekanik

Fredrik Larsson

Chalmers, Tillämpad mekanik, Material- och beräkningsmekanik

Magnus Ekh

Chalmers, Tillämpad mekanik, Material- och beräkningsmekanik

Computational Mechanics

0178-7675 (ISSN) 1432-0924 (eISSN)

Vol. 60 531-548

Ämneskategorier

Metallurgi och metalliska material

Styrkeområden

Materialvetenskap

DOI

10.1007/s00466-017-1419-y