.. _V1.01.342:

**v1.01.342** ZZZZ342 - Validation of ELAS_HYPER in small disturbances
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**Summary:**

This test validates the ELAS_HYPER law of behavior:


* compared to an elastic linear calculation (Hooke's law) under the hypothesis of small disturbances (HPP);


* by verifying, in compressible form, the equivalence of the formulation depending on whether the Poisson's ratio :math:`\nu` or the compressibility module :math:`K` is entered;


* by comparing the total formulation (formulation by default) and incremental (formulation imposed by the presence of an initial state) of the law of behavior.

A cube with side :math:`1\mathit{mm}` is embedded at its base and subjected to a loading of uniform pressure equal to :math:`1\mathit{Mpa}` at the other end. The material is Neo-Hookean (:math:`\mathit{C10}\mathrm{=}300\mathit{Mpa}`, :math:`\nu \mathrm{=}\mathrm{0,25}`).

The reference solution is of type AUTRE_ASTER and it is obtained by an elastic linear calculation with Hooke's law for an equivalent Young's modulus under the hypothesis of small disturbances (:math:`E\mathrm{=}1500\mathit{Mpa}`).

The results obtained in terms of movements and constraints are in very good agreement with the reference.

This test includes three models:


* modeling A: D_ PLAN


* B modeling: C_ PLAN


* C: 3D modeling

The A and C models are also the subject of calculations in GREEN_LAGRANGE kinematics.

This documentation is deliberately brief.