Multiframe allows you to use four basic types of members end releases. These are members that are pinned or rigid at one or both ends. If "rigid", they can transmit moments at the end, or if "pinned" they cannot transmit moments.
To set the member releases
§ Select the member or members to be pinned
§ Choose Member Releases from the Frame menu
A dialog box will appear with icons indicating the four types of member releases.
§ Click on the icon that represents the type of member, you require
or
§ Click on the individual degrees of freedoms to select which are released.
§ Click on the OK button
When you specify the type of a member you have control over which degrees of freedom are released at the pinned ends of a member. You can release any of the three rotations at each end of a member. This helps prevent the problem of torsional mechanisms being created when a group of connected members all have the Tx' action released. To help prevent this, the default settings for a pinned end only release the major and minor rotations (My' and Mz'). You may also select to release the axial force at either end of the member. Shear releases are not available in Multiframe via this dialog. However they can be simulated using member end springs with no stiffness. These are described elsewhere in this manual.
The members in the Frame window with pinned ends will be drawn with a circle near the ends that are pinned. Although the pins are shown to be a small distance from the end of the member in the Frame window, for the purposes of analysis they are in fact infinitely close to the ends of the member. A pinned end releases moments about the local member axes.
Note that the assumed member releases are initially set to rigid/rigid and it is not necessary to explicitly define any releases on a member, unless you have previously set the member releases to rigid/pinned, pinned/rigid or pinned/pinned.
You can change the member releases on a member by double clicking on the pin icons at the ends of the member.