u3.12.04 Modeling GRILLE_EXCENTRE, GRILLE_MEMBRANE, and MEMBRANE

Summary:

This document describes for models GRILLE_EXCENTRE, GRILLE_MEMBRANE, and MEMBRANE:

• the degrees of freedom carried by the finite elements that support modeling,

• the related support meshes,

• the materials and loads supported,

• calculation options for elementary matrices and post treatments,

• non-linear possibilities as well as fracture mechanics options if they exist.

Modeling GRILLE_EXCENTRE (Phenomenon: MECANIQUE) corresponds to finite elements whose support cells are triangles with three nodes and is used to represent reinforcements for shell-type reinforced concrete models. In fact, it makes it possible to take into account the eccentricity of the reinforcing layers with respect to the average sheet.

Modeling GRILLE_MEMBRANE (phenomenon: MECANIQUE) corresponds to finite elements whose support cells are triangles with three or six knots and quadrangles with four or eight knots and is used to represent reinforcements for 3D massive reinforced concrete models. Indeed, it does not allow eccentricity to be taken into account and therefore does not require a degree of freedom of rotation, which is useless in 3D modeling.

Modeling MEMBRANE (phenomenon: MECANIQUE) corresponds to finite elements whose support cells are triangles with three, six or seven knots and quadrangles with four, eight or nine knots and is used to represent any linear membrane behavior or a nonlinear isotropic membrane behavior. It does not allow eccentricity to be taken into account and only has degrees of freedom of movement.

• 1. Discretization
  • 1.1. Degrees of freedom
  • 1.2. Support mesh for stiffness matrices
  • 1.3. Cargo support mesh
• 2. Meaning of symbols
• 3. Assignment of characteristics
• 4. Supported materials
• 5. Supported loads
  • 5.1. Order AFFE_CHAR_MECA
  • 5.2. Order AFFE_CHAR_MECA_F
• 6. Nonlinear possibilities
• 7. Elementary matrix calculations
• 8. Post-processing of the calculation
  • 8.1. CALC_CHAMP options