Dave/Richard,

I am attempting to create a simple model of an expansion joint as a zero-length element while imposing an axial restraint, I am running into error #937. Details below...

Example:- start of joint = node 1010; end of joint = node 1015;
length of joint = zero; all exp joint parameters (axial, bending, etc.) have been filled in;

Restraint:- node:1010, Cnode:1015, type: LIM, gap: 0.

The following error is resulting:-
"Fatal Error # 937
Have zero length error on element used to define guide restraint direction cosines."

I have found that if I remove the restraint from this element (the 1010-1015 element) and move it onto the prior element (therefore 1000-1010), while still naming the restraint exactly the same (all of the same input mentioned above), the error disappears and the results appear to be correct!

Can you explain this problem I am having? Is this a known issue? I do not recall facing this problem in the past.

Regards,
Ryan

Use global definitions (X Y Z or skew) for zero length elements or define the restraint using local orientation (GUIDE LIMIT) on a non-zero element in the same direction.