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Hi all,

I have tried to download the parallel version of Opensees3.0.3 but it redirects to a non-existing page.
Could you please solve the issue? I cannot even download a previous version.

Thank you and best regards,

Corrado

Dear all,

Recently an OpenSees version based on Python has been released (http://openseespydoc.readthedocs.io/en/ ... index.html). Looking at the documentation I have noticed that there is lots and lots of stuff (Materials, Elements, Recorders...) which is probably in the official version 2.5.0 but not referenced in any way in the documentation. Is there any updated documentation available anywhere?

Regards,

Corrado

Dear selimgunay,

Thank you for your response. I cannot find any answer to my questions from the documentation, except for (maybe) setMaxOpenFiles command to set the maximum limit for the recorders, which I have not tried yet. The commands you suggested do not explain i) how the fibers are numbered, ii) how to output the number of fibers in a section, iii) what the meaning of "matArg1" is.

To make question ii) clearer, I would like to know if there exists a command similar to getNodeTags, but referring to fibers, something like "getNumberOfFibers $sectID". Alternatively, if there is a workaround for this.

Any other suggestions?

Corrado

Dear all,

I have reinforced concrete structure, where the members are modelled as forceBeamColumn with fiberSec section. I would like to output stress-strain relationships for EACH fibre (say N) and for EACH Gauss point (say M). As I can understand, I should create NxM recorders, but apparently there is a limit for the number of recorders. Furthermore, I cannot understand how to iterate over the number of fibres, and how are they numbered, i.e. I would like to know, given a fiberSec section, how many fibres have been defined. So, my questions are:

- What is the limit for the number of recorders, and how can I set it?
- How can I retrieve the number of fibres in a section in any part of the tcl model, i.e. without storing it when I build the section?
- What is the meaning of 'matArg1' in the command output 'fiber $fiberNum $matArg1 ..' (http://opensees.berkeley.edu/wiki/index ... er_Section)?
- How are they numbered (referring to fibreNum of the previously mentioned command)?

Thank you for any help.

Corrado

Dear all,

I found a very strange behaviour for the Hysteretic uniaxial material model. Apparently, in the unloading phase of a cyclic quasi-static test it uses the "maximum" stiffness of the backbone curve, instead of the "initial" one. This may give rise to unexpected behaviour when the material backbone curve is not defined as stiffness-decreasing.

I prepared a short example to show this strange behaviour. Basically, the model is represented by a single zero-length element which has one end fixed and a displacement history at the other end. This displacement history is an increasing ramp up to 20mm and then a decreasing ramp until 0. In other word, there is a loading semi-cycle. The material is defined such as the elastic limit is 30mm, and thus it should remain elastic during the whole loading history. With this constraint, two Hysteretic materials are defined: the first (applied to dof 1) has a degrading stiffness after the elastic limit, i.e. a stiffness which is LESS than the initial one; the second (applied to dof 2) has an increasing stiffness after the elastic limit. Since the zero-length element dofs are uncoupled I applied the same loading history to both dofs to see the differences in the material response. You can clearly see that the unloading stiffness of the second material is different from what should be expected, given that the material has not passed the elastic limit.

wipe
#create the ModelBuilder object
model BasicBuilder -ndm 3 -ndf 6

# add nodes - command: node nodeId xCrd yCrd
node 1 0.0 0.0 0.0
node 2 0.0 0.0 0.0

## read material
set K 5000.

uniaxialMaterial Hysteretic 1 [expr $K*30] 30 [expr $K*30*1.01] 45. [expr -$K*30] -30 [expr -$K*30*1.01] -45. 1 1 0.0 0.0
uniaxialMaterial Hysteretic 2 [expr $K*30] 30 [expr $K*30*2.0] 45. [expr -$K*30] -30 [expr -$K*30*2.0] -45. 1 1 0.0 0.0

# add zero-length elements
element zeroLength 1 1 2 -mat 1 2 1 1 1 1 -dir 1 2 3 4 5 6

# set the boundary conditions - command: fix nodeID xResrnt? yRestrnt?
fix 1 1 1 1 1 1 1

set incrOutput 1.
set initialTime 0
loadConst -time [expr $initialTime-$incrOutput]

#TimeSeries
timeSeries Path 1 -time {0. 50. 100.} -values {0 20 0 }
#set load on node 2
pattern Plain 1 1 {
sp 2 1 1.0
}

pattern Plain 2 1 {
sp 2 2 1.0
}


#set recorder for reaction and displacement
recorder Node -file rot.txt -node 2 -time -dof 1 2 disp
recorder Node -file mom.txt -node 2 -time -dof 1 2 reaction

# Cyclic loading to the model by Disp. control
constraints Lagrange
numberer Plain
system BandGeneral
variable TolStatic 1.e-6; # Convergence Test: tolerance
variable maxNumIterStatic 400; # Convergence Test: maximum number of iterations
variable printFlagStatic 0; # Convergence Test: flag used to print information on convergence (optional) # 1: print information on each step;
variable testTypeStatic EnergyIncr ; # Convergence-test type
test $testTypeStatic $TolStatic $maxNumIterStatic $printFlagStatic;
algorithm KrylovNewton;
integrator LoadControl $incrOutput
analysis Static
analyze 101; #steps

Dear all,

I would like to understand (and report in a paper) the exact formulation of the degradation rules for the Hysteretic material.

Unfortunately, no academic reference is provided in the manual (expect for the qualitative aspects shown in http://opensees.berkeley.edu/OpenSees/m ... l/4052.htm) and I am not able to formulate these rules reading from the source code.

Please can anyone help me with any reference?

Thank you and best regards,

cchisari