Error when using Bilin Material

[zsherliza]

Dear Vesna,
I am trying to simulate a collapse in my 3D bridge structure (I hope this is possible). I have read the example by Laura Eads and adopted her example into my work, however, when I try to run
my script it says "can't read sec_p1" no such variable. For your information, I have set sec_p1 as the Bilin material, my column are assigned the beamWithHinges elements, and I am using OpenSees
version 2.3.0. Why did I get this error?

Thank you, looking forward for some explanation.

[vesna]

It looks to me that you are trying to use $sec_p1 before it was really defined. Make sure you define it before using it for the first time. Also, there is a bug in the model you are looking at. Laura assigns equalDOF to the nodes that have the same coordinates as fixed nodes. This will create problems in eigen and dynamic analysis. Instead of using equalDOF when defining rotational spring for these nodes use fix command.