1. Discretization

1.1. Degrees of freedom

For three-dimensional multifiber beam modeling, the degrees of discretization freedom are, at each node of the support mesh, the six displacement components (three translations and three rotations). These knots are supposed to describe a segment of the average fiber of the beam.

Finished element	Degrees of freedom (at each vertex node)
POU_D_EM	DX	DY	DZ	DRX	DRY	DRZ

1.2. Support mesh for stiffness matrices

Finite element support meshes, in displacement formulation, are segments with two nodes SEG2:

Modeling	Mesh	Finished Element	Remarks
POU_D_EM	SEG2	MECA_POU_D_EM

1.3. Cargo support mesh

As for conventional beam elements (POU_D_E), all loads applicable to multi-fiber beam elements are treated by direct discretization on the support mesh of the element in displacement formulation.

No load support mesh is therefore required for the edge of the beam or bar elements.

1.4. Main characteristics of modeling

Modeling POU_D_EM is based on solving a beam problem where each defined section is divided into several fibers.

Each fiber then behaves like an Euler beam, that is to say that the sections remain straight and perpendicular to the average fiber (hypothesis of great slenderness).

The section may be of any shape.