multiPlas - Dynardo GmbH

The global load step bisection can be disabled by choosing a large value for cutmax. In the case of a
local bisection, no hints are written out.
Be careful not to use too large values for maxinc and simultaneous suppression of the global bisection.
This may lead to a large computational effort in a Newton-Raphson-Equilibrium iteration! In this case,
request the cause by use the global bisection!
Multi surface plasticity fundamentally is a physical path dependent phenomenon. Therefore a global incrementation
in order to represent the relocation of force correctly is of utmost importance.
In the multi surface routines, softening (residual strength) is only introduced in at the equilibrium states
(so only after reaching the global Newton-Raphson equilibrium). Therefore, a global incrementing is important
in the case of softening.
The value dtmin in the tb-data-fiel has to be identical to the value of dtmin that is used by ANSYS in the
solution-phase (deltim,dtanfang,dtmin,dtmax,...).
If no convergent solution could be found:
-decrease incrementation (dtmin,...)
-increase the global convergence criteria (cnvtol,f,...)
Newton-Raphson, full (usage of consistent elasto-plastic tangent) or Newton-Raphson, init (starting stiffness)
is supported. For the practical problems Newton-Raphson, init is recommended. Especially when
considering geometric nonlinearities or when working with EKILL / EALIVE the full Newton-Raphson
method is necessary.
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USER’S MANUAL, January, 2013