Orthotropic

The orthotropic option recognizes the structural orthotropy of plates and shells. Structural orthotropy refers to the lack of uniformity of plate stiffness in different directions, due to, for instance, plate ribbing. Orthotropy recognizes differences in stiffness in the mutually perpendicular directions, but it does not recognize the lack of uniformity of the material. All the geometrical heterogeneities are recognized only in the stiffness matrices of elements. A plate with a thickness defined in this way should be treated as a structure with equivalent thickness but different stiffnesses in perpendicular directions.

Note: Local change of rib stiffness is not recognized; the exact plate geometry is not visualized and it is not recognized during calculations of reinforcement.

Specify orthotropic thickness parameters:

Label - define a name for a thickness.
Color - select the panel color.
Direction X - click this to open the Orthotropy direction dialog, where you can define the main orthotropy direction.
List with available types of predefined plate geometry (such as ribs, box floor, grillage, and trapezoid plate). If you select the user-defined option, you can create a custom orthotropy matrix: after selecting a plate geometry type, the relevant edit fields are available that allow you to define the plate dimensions.
Display or Define - click this to open the Stiffness matrices dialog. The Define button displays after you select user-defined on the list of predefined plate geometry types.
Thicknesses - when this is selected, you can define the thickness values:
- Th - the equivalent thickness used to calculate the plate self-weight.
- Th1 - used to define the equivalent thicknesses used for calculations when applying thermal gradient loads.
- Th2 - used to define the equivalent thicknesses used for calculations when applying thermal gradient loads.
  The thickness values are calculated automatically on the basis of the geometrical plate parameters.
Parameters of foundation elasticity (elastic support coefficient K) - click this to open the Definition - Elastic Foundation dialog.
Material

Note: Reinforcement calculations for this type of plate will not provide correct results. A new algorithm for plate reinforcement should be implemented that would recognize a T-section or an H-section. Therefore, the reinforcement calculations for this type of plate are carried out as if they were homogenous plates with invariable cross-section.

After you have defined the parameters, click Add. The newly defined thickness type will be added to the list of active thickness types.