Parametric connections

To create a parametric connection:

• Open the connection library and hit . The following dialogue appears:
  
• Name
  Give the connection a name.
• Limitations – if you assign this connection to a selection of bars, how should the selection look like?
  • Number of bars
    A connection can consist of 1 or 2 bars.
    In case of 2 bars, the connection has a ‘main bar’ and a ‘secondary bar’. The stiffness function will be assigned on the secondary element.
  • Connection type
    The connection type can be along the strong or weak axis (of the main bar).
  • Minimum & maximum angle between bars
    In case of 2 bars, you can limit the angle between the bars with the minimum and maximum angle.
  • For both main and secondary element, you can allow:
    • For the cross-section
      • Any shape
      • A specific type of shapes {list}
      • One specific cross-section from the section library
    • For the material
      • Any material
      • A specific type of material
      • One specific material

• Image
  Each connection can have an image.
• Resistance and stiffness
  Six components can be taken into account in the calculation, if the corresponding checkbox is ticked.
  The prime (‘) refers to the local coordinate system of the element. It can be visualized on the screen by editing the Window Configuration .
  • Torsion Tx’
  • Bending moment My’
  • Bending moment Mz’
  • Shear Vy’
  • Shear Vz’
  • Normal force N

For each of these internal forces you can impose the stiffness, resistance and interaction.

Stiffness

For each of the internal forces, you can impose a stiffness diagram by clicking on . The following dialog appears:

Here you set the stiffness behaviour for the component being negative (< 0, top part) and positive (>0, bottom part). Either you select one of the predefined states – fixed, free or value (value required) or you add a user-defined diagram by entering multiple sets of values for

• (φ, M) for moment components
• (u, F) for shear or normal force components

Resistance

For each of the internal forces, you can impose enter a negative (< 0, first value) and positive (>0, second value) value for the resistance.

Diamonds will check the resistance of each component individually, by comparing the acting force F_Ed to the resisting force F_Rd. The result should be less than 1:

   

F_Rd corresponds to the entered resistances in the image above.

Interaction

For connection verification purposes, you can enter one or multiple interaction formulas for the component resistance. Already entered formulas accessible through the pull-down list. As Diamonds automatically checks the resistances for the components individually, it is unnecessary to add them here.

You can add , modify and remove formulas.

To add a new interaction formula:

• Click on . Tthe following dialogue appears:
  
• Enter a name for the interaction formula.
• The internal forces (components) checked in the previous dialog, are shown in black and are available for use in the interaction formulas. Unchecked intenral forces are disabled.
  
  To include a component to the formula, you thick the check box. Components will be added as the acting force divided by the resisting force F_Ed/F_Rd. This ratio can be multiplied with a factor and put to a power– in the ‘Parameters’ section.
  It is possible to assign the component to a group. A group consists of one or multiple components put ‘between brackets’. This group can also have a multiplication factor and a power.
  Note that the power is not limited to integers, you can enter for example a square root with a 0.5 value.
• At the bottom of the window, you immediately see the formula appearing, allowing easy visual verification and modification. The entire formula should result in a value less than 1, in order to have an acceptable connection verification.
• Click ‘OK’ to save the interaction formula or made modifications to it.