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Hi all,
I am stuck up in characterizing the parameters for pinching 4 material. The command is as given below.
uniaxialMaterial Pinching4 $matTag $ePf1 $ePd1 $ePf2 $ePd2 $ePf3 $ePd3 $ePf4 $ePd4 <$eNf1 $eNd1 $eNf2 $eNd2 $eNf3 $eNd3 $eNf4 $eNd4> $rDispP $rForceP $uForceP <$rDispN $rForceN $uForceN > $gK1 $gK2 $gK3 $gK4 $gKLim $gD1 $gD2 $gD3 $gD4 $gDLim $gF1 $gF2 $gF3 $gF4 $gFLim $gE $dmgType

I am unable to understand the last 17 parameters. They are related to strength and stiffness degradation. But even if I put them as "0", still I am
able to get the output. But will it be correct? What would be the difference?
(or) is there a way to get these parameters.


Thank you...

I checked, but couldn't find any wrong in unit conversions. My units are consistent.

I am doing pushover analysis for a frame with non-linear connections. When a apply lateral displacement controlled loading in steps (as we do in a non-linear analysis), I am able to get the load-displacement curve of the frame.

But there is one issue. The curve I am getting is of the same shape as the experimental counterpart, but its scaled down around 12 to 16 times
on the force axis. i.e. when I multiply the output force values (reactions at the supports) by some value, say 12.3, I am getting the exact load - displacement curve. I am unable to understand why there is such scale down. Displacement axis is matching exactly.

Kindly help me out, please!

Thank you.

Thank you sir,
I found the error. but again it is showing this warning-

WARNING TwoNodeLink::setup() - element: 40
ignoring nodes and using specified local x vector to determine orientation.
It's a 3-D model
I am working in X-Z plane and the link is between nodes parallel to z axis. In that case my vectors are:
$x1 $x2 $x3 and $y1 $y2 $y3
0 0 1 -1 0 0

still it is showing the warning.
Finally I also have a LAPACK error:
BandGenLinLapackSolver::solve() -factorization failed, matrix singular U(i,i) = 0, i= 421
DisplacementControl::newStep(void) - failed in solver
StaticAnalysis::analyze() - the Integrator failed at iteration: 0 with domain at load factor 0
OpenSees > analyze failed, returned: -2 error flag

Can you help me out?

Thank you,
Ashok.

My opensees.exe gets vanished in a flash (unable to see any errors) when I create a twoNodeLink element

Can anyone kindly help me!

Thanks in advance,
Ashok