Member Specification (KMX, KMZ)

Hi,

I wish to know how and when to assign values for KMX and KMZ (unit: kN-m/deg.).

I've seen members with either KMX =0.001 or KMZ=1 or KMY=1 but I need to fully understand how did they get these values and why.

There are members with "checked" END MY (not free to rotate at Y) understanding its member-end and connection must be designed free to rotate only at X and Z but I have no confident understanding on values to use for KMX, KMY and KMZ.

Looking forward for someone who could help me.

Thank you very much in advance.

Regards,

Chelle