Warning in Ansys 1

[civilmh]

Hello,
I am analysing a 3-D model of concrete column under axial load. The concrete is modelled by Solid45 Element with William-Warnke for material of the concrete. The solution converges to the true results for small loads (approximately for 20 % of ultimate loads) but for larger loads does not. The warning message is “there are 2 small equation solver pivot terms”.
Please help me if you have any idea.
thanx

 

[Drej]

Pivot warnings suggest boundary conditions (ie a poorly constrained model) or possibly there could be local failure within the model. Check for under- and over-constraints.


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[civilmh]

I am analysing a 3-D model of Circular concrete column under Axial load.
The concrete is modelled by Solid 65 With William-Warkne Criteria Failure.
The Dimension Of The Column Is (D=152 mm , H= 305 mm) That The DOFs(Dx-Dy-Dz-Rx-Ry-Rz) Of the Bottom Is Constraint.
The solution converges to the true results for small loads (approximately for 20 % of ultimate loads) but for larger loads does not.
The warning message is “there are 2 small equation solver pivot terms”.
I Think That Resoan of this warning due to crushing in concrete.
If The Uniaxial Crushing Stress be -1,the warning disappear
but property of crushing disabled,and this property is important for me.


Please help me if you have any idea

Thaks alot