.. _U3.12.03: **u3.12.03** Modeling COQUE_3D ================================== **Summary:** The modeling COQUE_3D presented here corresponds to a formulation of the general kinematics of shells and plates, of the Naghdi-Reissner type, where the generalized constraints are obtained from the laws of three-dimensional behavior of the constituent materials [:ref:`R3.07.04 `]. Unlike the DKT - DST models, Q4G corresponding to the formulations of plate elements developed by J.L. BATOZ [bia1] _ which use plane finite elements, the COQUE_3D modeling makes it possible to perform calculations of shell structures of any shape, with a good approximation of the geometry. In addition, this modeling is capable of representing the large rotations of structures [:ref:`R3.07.05 `] under the hypothesis of small deformations. The degrees of freedom are the movements and the rotations, taken at the nodes of the elements. The nonlinear behavior is discretized by :math:`\mathit{P2}` polynomials, which allows precise calculation of the constraints. It can be used for three-dimensional shell structure problems in linear and nonlinear mechanical analysis. This formulation also exists for slice problems, or revolution problems. It is based on 1D elements: (see [U3.12.02]). Thermomechanical calculations are linked using the finite elements of thermal shells (see [:external:ref:`U3.22.01 `]). .. toctree:: :hidden: self .. toctree:: :maxdepth: 2 :numbered: Discr_tisation Affectation_des_caract_ristiques Chargements_support_s Possibilit_s_non-lin_aires Exemples_de_mise_en__uvre___cas-tests Bibliographie