Torsional Spring in ANSYS Workbench

Torsional springs can come in handy when inertia plays a large role in the dynamic response. Fortunately a simple snippet converts a typical linear spring into a torsional spring. Workbench uses COMBIN14 springs by default.

keyopt, _sid, 3, 1 ! rotational DOF about spring axis
r, _sid, 0.01 ! rotational stiffness

Torsional Mode due to Torsional Spring

One could also specify the radial stiffness of the spring above by specifying the direction. Note that KEYOPT(2)=1.
keyopt, _sid, 2, 1 ! UX direction about global axis
r, _sid, 1e5 ! Translation stiffness

Same goes for off-axis rotational DOF via KEYOPT(2)=4.
keyopt, _sid, 2, 4 ! ROTX direction about global axis
r, _sid, 1e5 ! Rotation stiffness

The Workbench (v18.2) Archived File: LINK

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