# (U2.04.07) Using methods of transient solving for quasi-static highly nonlinear problems

http://www.code-aster.org/V2/doc/default/en/man_u/u2/u2.04.07.pdf

**Résumé:**
This document presents the use of methods of transitory resolution (implicit or explicit) for computational simulation of quasi-static problems presenting of strong non-linearities materials. One only seeks to obtain solutions where the ram effects are negligible.
These methods of resolution (based on the use of DYNA_NON_LINE) are conceived as an alternative to the usual quasi-static approaches of Code_Aster (based on STAT_NON_LINE) when they prove to be unable to converge in an acceptable time. That can be the case for applications implementing damaging materials.
The methods which are the object of this document are of two types:

- implicit transitory resolution,
- resolution clarifies pseudo-dynamics.

The choice will be depend on the nature of the problem to treating, in particular, in restrain with the scales of time considered. The use of these strategies being more delicate than the quasi-static approach, they are to be held for the most problematic cases. The reading of U2.06.13 documentation strongly constitutes pre-necessary advised: the general advices of use of DYNA_NON_LINE remain relevant.