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Yes, I just noticed that. The load is applied at the local x-axis.

It is not possible. You can try to explain the problem or, if possible, copy the line of code that has the problem, and I will try to help you.

Can you provide more explanation for your problem?

Anyway,

I have had a problem with eleLoad a while ago, but it ultimately worked with me:
http://opensees.berkeley.edu/community/ ... =2&t=64317

This example shows how to apply cyclic load:
http://opensees.berkeley.edu/wiki/index ... rtal_Frame

You may need to have a look at this:

https://ascelibrary.org/doi/10.1061/%28 ... 2%28244%29

ConfinedConcrete01 is based on Braga and Laterza (2006) model, while concrete 02 is based on Yassin (1994) work. Hence, they would definitely show some differences in behaviour.

Regarding your period change, why don't you just test whether you run the model correctly by following the examples given the ConfinedConcrete01:
http://opensees.berkeley.edu/wiki/index ... 1_Material

I started by following these examples, and gradually got a sense of every input parameter. Feel free to ask me about any of them.

Regarding FRPConfinedConcrete, I honestly can't remember exactly which example I followed, but I think the one provided on the page worked with me.

I am sure there is something wrong in your input of the parameters in both models, which leads to the change in period. You may start off by doing it for the uniaxial test to make sure, from the stress-strain curves, that you get the model right, like in the examples given in the link above.

I have tried both FRPConfinedConcrete and ConfinedConcrete01, and they showed similar results. However, I would recommend ConfinedConcrete01, as it requires less info. It has been used in many studies over the past few years.

You may need to check the rigidity of the beam between the two columns. It may be hard to obtain convergence if it has large rigidity. I have faced a similar issue in one of my models.

I am not sure about the coordinates directions of your model, but I think you need to double check the fixity. You are using fix 1 0 1 1 1 1 1. Remember that you need to restrain Vy, Vz and T.

Yes, I am currently facing a similar issue with convergence for higher intensities. I just posted a question on it recently:

http://opensees.berkeley.edu/community/ ... =2&t=65708

I am using Plain numberer and got differences in results (post-peak) when I used more than one element.

In my case, the differences are actually in static analysis. I did not check the dynamic analysis.

I am not actually sure about the source of this problem, but if you really need to model your structure using more than one element, you may try to use displacement beam-column element, but you will need to provide many elements to get close results to the one element model using force beam-column.

As a beginner, I would strongly advise you to follow the OpenSees basic examples available through the link below. Have a look at them and then start coding a model or two yourself by referring to the explanation provided in each example.

It can be a little hard at the beginning, but by the time you will be able to model any structural element. It is also not a bad idea to sketch the structural elements with their nodes coordinates, fixities, and transformations (if the model is 3D) in their respective both global and local axes to avoid getting confused.

OpenSees examples:
http://opensees.berkeley.edu/wiki/index.php/Examples

Thanks Ericson for your reply and sorry for the delay in getting back to you.

The elastic section is given the normal properties of a column. I also increased the elastic section stiffness, but it still does not change the results. My model is actually in mm, tonne, sec and N.

To make it easy for me to explain my model, I am copying below a similar code of what I am trying to do:

node 1 0.0 0.0 0.0
node 3 0.0 2000.0 0.0
# -----------------------------------------
# Boundary Conditions
fix 1 1 1 1 1 1 1
fix 2 1 0 1 0 1 0

# -----------------------------------------
# Geometrical transformation
geomTransf PDelta 1 1 0 0
geomTransf Linear 2 1 0 0

# -----------------------------------------
# -----------------------------------------
# UNIAXIAL MATERIAL PROPERTIES
# 1. Concrete

uniaxialMaterial Concrete04 1 [expr -1.2*31.0] -0.005 -0.051 28000.0 2.37 0.0021

# -----------------------------------------

# 2. Steel

uniaxialMaterial Steel02 2 414 206842.7 -0.01 18 0.925 0.15 0.0 1.0 0.0 1.0

# -----------------------------------------
# -----------------------------------------

# CIRCULAR FIBER SECTION
# Section fiber

section Fiber 3 {
set u 100.0

set ro 500.5

set rc [expr $ro-$u]

set numbar 14

set arbar 3000.0


patch circ 1 32 30 0 0 0 $ro 0.0 360.0



# Steel reinforcement
layer circ 2 $numbar $arbar 0 0 $rc

}
# -----------------------------------------
# -----------------------------------------

# ELEMENTS

# Number of integration points
set np 5

# 1. Zero-length springs section
element zeroLengthSection 1 1 2 3 0 1 0 0 0 -1





# 2. Intermediate rigid element between zero-lenth springs

set A 190000.604
set E 26000.0
set G [expr $E1/(2+0.4)]
set Iz 3.7E+13
set Iy 3.71E+13
set J [expr $Iz1+$Iy1]

element elasticBeamColumn 3 2 3 $A $E $G $J $Iy $Iz 2

Hi,

I am running a dynamic (time-history) analysis of a single degree of freedom (SDOF) model using distributed plasticity (dispBeamColumn element).

I am using the below code to run my analysis. I tried to improve the convergence by using the different alternative algorithms of the analysis code of example 7 (Portal frame EQ distributed), but it did not improve it.

Can anyone please check my code below, and if possible, give me any suggestion on how to improve the convergence?



# 2. Analysis
# System of equations
system BandGeneral
#system FullGeneral
numberer Plain
# Constraint handler
constraints Transformation
# Convergence test
test NormDispIncr 1.0e-6 100
# Integrator
integrator LoadControl 0.1
# Solution algorithm
algorithm Newton
# Analysis object
analysis Static

for {set i 1} {$i < $NumSteps} {incr i} {

set ok [analyze 1 $dt_analysis]

set ok 0; break;
}
if {$ok != 0} {

Hi,

I am trying to model a cantilever using zero-length section elements at its both ends while the middle element is elasticBeamColum element.

I would like to capture the response of cantilever based on the fiber section defined for the ZeroLengthSection element at both ends.

The nodes arrangement is as follows ( in 2D):
[Node 1] ----- ZeroLengthSection element ----- [Node 2] ----- elasticBeamColum element ----- [Node 3] ----- ZeroLengthSection element ----- [Node 4]

Node 1 is fixed (fix 1 1 1 1)
Node 4 is fixed at the rotation only (fix 4 0 0 1)

I have added Vy to the fibre section of the ZeroLengthSection element, using section Aggregator command.

However, the pushover results show linear elastic behaviour. It tried to replace the elastic Beam Column element with a nonlinear forceBased element, and the results changed to nonlinear.

This means that the model results are based on the middle element not on the ZeroLengthSection elements.

Can anyone please help me with this?