Plastic hinge library
You can access the plastic hinge library using the following option, which is available in the "Project" section of the top toolbar, within the "Project" tab (under the "Structure" sub-tab).
The plastic hinges created here can be selected and used when inserting plastic hinges into rods via the "Plastic hinges" option on the "Rods" tab.
List of plastic hinges
The list of plastic hinges that appears when you open the "Plastic hinge library" features a series of options at the top for "Add", "Edit", "Copy", "Delete" and reordering hinge types, as well as for importing and exporting the elements defined here to files on the hard drive.
When defining the properties of each plastic hinge, you must specify a "Reference" and choose between two types:
- Elastic-linear Hardening
- Modified Ibarra-Medina-Krawinkler
In addition, the "Colour of plastic span" is defined; this colour will be used to highlight hinges that have reached the plasticity point in the stress display.
Hinges with elastic-linear hardening
The data required to define the behaviour of a plastic hinge with "Elastic-linear hardening" are the "Plastic moment" and the "Hardening ratio" (or slope in the plastic region).
In the "Plastic moment" drop-down menu, you can choose to have the program calculate this value automatically – which is possible for steel sections with a known plastic modulus – or enter it manually in all other cases.
Ibarra-Medina-Krawinkler hinges
"Modified Ibarra-Medina-Krawinkler" type plastic hinges allow the behaviour of resistance and stiffness reduction following plasticisation to be modelled using a backbone curve.
The data required to define the behaviour of a plastic hinge in a given degree of rotational freedom are as follows:
- Plastic moment (Positive, Negative)
- Hardening ratio (Kp/Ke) (Positive, Negative)
- Plastic rotation capacity (Positive, Negative)
- Limit plastic rotation capacity (Positive, Negative)
- Residual resistance ratio (Mr/My) (Positive, Negative)
- Ultimate rotation capacity (Positive, Negative)
The data entry panel features a help button that displays the hinge’s performance curve and a legend explaining the parameters that define it.
