Python Element recorder

[zashurow]

Hello,

I am new to opensees and am converting some existing code from tcl to python. I am struggling with converting the following element recorder:

recorder Element -file $DataDir/StrainT.out -ele 1 section fiber -10.75 0. stressStrain

What I currently have is:
recorder('Element', '-file', DataDir+'/StrainT.out','-closeOnWrite', '-ele',1, *['section',1, 'fiber',[-10.75,0], 'stressStrain'])

I am getting stress-strain values, but they are incorrect. I suspect it is something to do with defining the coordinates (-10.75,0) because changing the numbers does not change the results.

Does anyone know what I am doing wrong?

Thanks

[selimgunay]

You might be defining your section incorrectly. I would use an elasticmaterial and check against analytical results (leT's say using sigma=My/I)

[ahankariindian]

I am having a similar problem for stressStrain recorder in openseespy.

Here is what I did:

I downloaded both .tcl and .py examples of the pushover analysis of RC Frame from the respective websites. I added two lines of code in each example to record the stress-strain values at two different fibers. The same two fibers were used in both .tcl and .py versions of code.

.tcl additional lines of code:

recorder Element -file stress1.out -time -ele 1 section 1 fiber [expr $y1-$cover] [expr $z1-$cover] stressStrain
recorder Element -file stress2.out -time -ele 1 section 1 fiber [expr $cover-$y1] [expr $z1-$cover] stressStrain

.py additional lines of code:

recorder('Element', '-file', 'stress1.out', '-time', '-ele', *[1], *['section', 1, 'fiber', [y1 - cover, z1 - cover], 'stressStrain'])
recorder('Element', '-file', 'stress2.out', '-time', '-ele', *[1], *['section', 1, 'fiber', [cover - y1, z1 - cover], 'stressStrain'])

Note that the fibers I picked are on either side of the neutral axis and hence I expected one to be in tension while other in compression. .tcl version gave me meaningful results. However, .py version gives me the same numbers regardless of what fiber I choose. The numbers are also not consistent with the .tcl output. Is this a problem with the recorder object in openseespy?

Also note that the forces and deformations of the element from both versions match exactly.