During the calculation, I get an error message in RFEM with Error No. 1639, or in RSTAB with Error No. 1640: "Member No. XY and | Member hinges No. YZ are freely rotatable about the x-axis. Please check this in Table 1.17 (or 1.7 in RSTAB) or another related table." Can you please tell us more about activating and using this service?

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Accepted Answer

In fact, this error message only appears if a member hinge that allows a rotation about the local x‑axis has been assigned to a member at both ends. Thus, the member can rotate freely about its own axis and is therefore unstable.Assign a new release to one of the member ends where the degree of freedom φx is not hinged.

Error Message 1639/1640 for Free Rotation About x-Axis