# degree of freedom

## Stacking of DOFs in Abaqus

Free Tags:

I am studying the response of a bridge in MATLAB, and have successfully retrieved mass and stiffness matrices from Abaqus using the following keywords:

*Step

*Matrix generate, STIFFNESS, MASS

*Matrix output, STIFFNESS, MASS, FORMAT=COORDINATE

*End step

This gives matrices on a mathematical form, very well suited for use with MATLAB.

## DOFs in Abaqus

Hi,

I got a simple 2D problem (a rectangular shell, static general, CPS4R element), with 557 nodes, each of them have 2 DOFs (U1 and U2), according to the data file. But when I print out the ELEMENT STIFFNESS MATRIX, for each element it is a 12x12 matrix which means the rotational DOF about z axis is also taken into account. How can I omit this 3rd DOF? Can I?

Thank you.

## Help me : Node Print of User Defined Degree of Freedom

Hello Experts,

I have written a uel subroutine where I have totally 12 degree of freedom. Among these 12 degree of freedom, 6 are standard abaqus degree of freedom (3 Displacements and 3 Rotations) and another 6 are User defined degree of freedom.

I assign these these degree of freedom in following way.

*USER ELEMENT,TYPE =U9, NODES=9,PROPERTIES=24,coordinates=3
1,2,3,4,5,6
9,1,2,3,4,5,6,7,8,9,10,11,12

## Ansys Error what's going on ???

Dear All,

I have much problem when modelling my project with ANSYS, one of problem that I met always like this

*** ERROR ***                           CP =     296.828   TIME= 14:56:15
A small negative equation solver pivot term has been encountered at the
ROTZ degree of freedom of node 11758.  Check for an insufficiently
constrained model. 