# There is at least 1 small equation solver pivot term plz help!!

mohammed164
Member

in Structures

There is at least 1 small equation solver pivot term (e.g., at the ROTY

degree of freedom of node 348). Please check for an insufficiently

constrained model.

## Comments

Some part of the model is free to rotate about the Y axis. Add a constraint to stop that.

i'm sorry but how !!?

How many parts are in this model and how are they connected to each other? How is the model connected to ground?

THANK YOU AGAIN

IF you don't get upset!!

i have anther problem when i try to exchange line body from beam to truss he told switch to large deflection but in solver control can't find large deflection option !!??

THANK YOU

In Mechancial, under Static Structural click on Analysis Settings. Large Deflection is turned on there.

THANKS AGAIN

hi

when i change line body from beam to link/truss and solve, give me error

*** ERROR *** CP = 1.391 TIME= 22:05:43

There are 105 small equation solver pivot terms (e.g., at the UY degree

of freedom of node 304). Please check for an insufficiently

constrained model

and when modified element size in mesh to 10 and solve he give me that error

*** ERROR *** CP = 1.219 TIME= 22:10:58

There are 24 small equation solver pivot terms (e.g., at the UY degree

of freedom of node 182). Please check for an insufficiently

constrained model.

please helpppppp!!!!!

You need to set the Element size to a number larger than the total height of the model so that there is only 1 element on each line body. You only want one link element on each line. If the line body represents a wire, then you might want to set the element to be tension only so that it doesn't carry any compressive force.

Is it possible to have error because zero member?

same error !!!

*** ERROR *** CP = 1.219 TIME= 22:10:58

There are 24 small equation solver pivot terms (e.g., at the UY degree

of freedom of node 182). Please check for an insufficiently

constrained model.

What is a zero member?

like this !

no force, no tension, no Compression

Is it truss/link required to resolve custom settings ???

hi

I figure out what the problem and solved Except one element give me error

*** ERROR *** CP = 1.469 TIME= 22:420

There are 1 small equation solver pivot terms (e.g., at the UZ degree

of freedom of node 47). Please check for an insufficiently

constrained model.

i try every member and no thing !!!?

please help !!!

What are these lines across the section? That looks like there is a node/vertex at that point. If those are all Truss elements, that is no good. If those are Beam elements then it is okay.

that's what i figure out and fixed unless one member can't find

*** ERROR *** CP = 1.266 TIME= 22:24:46

There is at least 1 small equation solver pivot term (e.g., at the UZ

degree of freedom of node 100). Please check for an insufficiently

constrained model.

THAT ERROR

can't find that element !!!!

Add a Modal analysis to the Static Structural Model. Drag and drop any Fixed Supports or zero Displacement BCs. The offending part may reveal itself.

The text file you attached is not useful for finding the problem.

You can create a Named Selection to show which node is # 100. That would be helpful.

i try simple model and nothing, same error

i'm disappointment