structure node fix command


structure node fix keyword ... <range>

Primary keywords:

rotation    rotation-x    rotation-y    rotation-z    system-local    velocity    velocity-x    velocity-y    velocity-z

Fix the velocity-fixity conditions for all nodes in the range, thereby preventing these values from changing. The conditions are given in terms of the node-local coordinate system. If a velocity component is fixed, then the value of this component should also be specified in the node-local coordinate system via the structure node initialize command. If a fixed displacement is required, then the appropriate velocity components should be initialized to zero. A degree-of-freedom with a rigid attachment condition cannot be fixed; the rigid condition overrides the fix condition. The velocity-fixity conditions are freed with the structure node free command.


rotational velocity in all three rotational degrees-of-freedom (node-local system)

rotation-x (3D ONLY)

rotational velocity about \(x\)-axis (node-local system)

rotation-y (3D ONLY)

rotational velocity about \(y\)-axis (node-local system)

rotation-z (3D ONLY)

rotational velocity about \(z\)-axis (node-local system)


inhibits automatic updating of the node-local system based on the elements that use the node (as described here). The default behavior is free (see structure node free system-local).


translational velocity in all translational three degrees-of-freedom (node local system)


translational velocity in \(x\)-direction (node-local system)


translational velocity in \(y\)-direction (node-local system)

velocity-z (3D ONLY)

translational velocity in \(z\)-direction (node-local system)