Next: *BEAM SECTION Up: Input deck format Previous: *AMPLITUDE Contents

##
*BEAM GENERAL SECTION

Keyword type: model definition

This option is used to assign material properties to beam elements with a cross section which is neither rectangular nor elliptical. For the available beam general sections, please consult Section 6.3. Right now, only a pipe section is coded.

Notice that internally beam general sections are expanded into beams with a rectangular cross section (this is also the way in which the beam is stored in the .frd-file and is visualized in the postprocessor. The actual cross section is taken into account by appropriate placement of the integration points). The rectangular cross section is the smallest section completely covering the beam general section. For instance, for a pipe section the expanded section is square with side length equal to the outer diameter.

The parameters ELSET, MATERIAL and SECTION are required, the parameters ORIENTATION, OFFSET1 and OFFSET2 are optional. The parameter ELSET defines the beam element set to which the material specified by the parameter MATERIAL applies. The parameter ORIENTATION allows to assign local axes to the element set. If activated, the material properties are applied to the local axis. This is only relevant for non isotropic material behavior.

The parameter SECTION defines the cross section of the beam and takes the value PIPE for a pipe cross section. It is defined by its outer radius (first parameter) and its thickness (second parameter).

The OFFSET1 and OFFSET2 parameters indicate where the axis of the beam is in relation to the reference line defined by the line representation given by the user. The index 1 and 2 refer to the local axes of the beam which are perpendicular to the local tangent. To use the offset parameters direction the local directions must be defined. This is done by defining local direction 1 on the third line of the present keyword card. The unit of the offset is the thickness of the beam in the direction of the offset. Thus, OFFSET1=0 means that in 1-direction the reference line is the axis of the shell, OFFSET2=0.5 means that in 2-direction the reference line is the top surface of the beam. The offset can take any real value and allows to construct beam of nearly arbitrary cross section and the definition of composite beams.

First line:

- *BEAM GENERAL SECTION
- Enter any needed parameters.

Second line:

- first parameter
- second parameter

Third line:

- global x-coordinate of a unit vector in 1-direction (default:0)
- global y-coordinate of a unit vector in 1-direction (default:0)
- global z-coordinate of a unit vector in 1-direction (default:-1)

    Example:

    *BEAM GENERAL SECTION,MATERIAL=EL,ELSET=Eall,SECTION=PIPE
    .11,.01
    1.,0.,0.

assigns material EL to all elements in (element) set Eall. The section of the beam is a pipe section with outer radius 0.11 and thickness 0.01.

Example files: simplebeampipe1,simplebeampipe2,simplebeampipe3,simplebeampipe4.

Next: *BEAM SECTION Up: Input deck format Previous: *AMPLITUDE Contents