Hello C_A Community,
now I'm working with shell-like structures. I read that only shell modeling COQUE_3D supports nonlinear materials as well as nonlinearity in geometry. I'd tried analyse shell-like structure (see attachment), with weak isotropic hardening. I noticed that when plastic strains occurs, solver can't cope with problem, and returns exeption about singular matrice. I've done also similar analysis but, with ideal elasticity, and everything went ok . Singular problem always concerns about rotational DOF. In the mess file we can see:
!----------------------------------------------------------------------------------------------------------------------------!
! !
! !
! Option activée : pour les !
! Alarme : !
! L'algorithme de réactualisation des grandes rotations est tel que les rotations doivent être inférieures à 2 pi radians. !
! Assurez-vous que les rotations ne soient pas très grandes au risque de résultats faux. !
! !
! !
! Ceci est une alarme. Si vous ne comprenez pas le sens de cette !
! alarme, vous pouvez obtenir des résultats inattendus ! !
!----------------------------------------------------------------------------------------------------------------------------!
I suppose that together with plastic strains, occurs very large rotations of nodes, and due to above limitation of "GROT_GDEP" solver stops.
Is it any method to do shell analysis with substantial plastic strains? I will be glad if someone confirm my assumption/theory about the problem.
regards
Filjan
Attached file:
Orb.tar.gz, 54327kb
