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Dear all, I have a problem using Brick elements in transient analysis. I modeled a simple model of 5 brick elements. I tried static, modal and transient analyses on this model. While the results of static, modal cases are exactly like sap2000 results, the results I am getting for transient analysis ...

Hello, I want to model a masonry wall with varying thickness. The material model is nonlinear. I wanted to define nonprismatic brick elements with fiber section. (is this a good choice?) However, I do not know how I should define the fibers for such elements whose sections are changing.any idea? Als...

Hi all, I have a problem in running transient analysis on a nonlinear steel frame. When I define columns and beams with only two elements, I dont get any warning. But when I increase the number of elements in columns or beams (more than two) opensees.exe will be closed without any warning. Any idea ...

Hi all, My model is a 2span steel frame (with bilinear material, steel01 and fiber sections). When I run it , opensees will be suddenly closed and I can not figure out what is the problem. When I run it with only one nodes in the middle of the column and beam parts, it will finish the analysis witho...

Hi all; I am doing a transient analysis on a nonlinear frame, I keep getting this warning: WARNING: CTestEnergyIncr::test() - failed to converge after: 10 iterations ModifiedNewton::solveCurrentStep() -the ConvergenceTest object failed in test() DirectIntegrationAnalysis::analyze() - the Algorithm f...

Dear vesna, Thank you for your help, I fixed those two dofs for node 2, also modified my analysis object based on what you said. It still doesnt work at none of the time steps & gives me this warning 4000 times: "analysis failed, Newmark : : new step()-domainChange failed or hasn't beed called Direc...

Hi, I wanted to model a sdof system with one lumped mass and a nonlinear spring (bilinear) $ apply dynamic load to it. Here is my code. It does not work and I don't know where I am making the mistake. Can anyone help me please. The force is harmonic with T=3sec & Ampl=1. Could you also tell me how I...

Deal all;
Could anybody help me with this please?
In modal analysis,
Is there anyway to store mode shape vectors in different files without using (%i) symbol in the line below?

recorder Node -file [format "modes/mode%i.out" $k] -nodeRange 1 6 -dof 1 2 3 "eigen $k"

Thanks

Hi all,
Does anyone know how we can export model matrices ( M & K ) from opensees code?
Thanks

Hi all; I wanted to define a joint with three rigid links,(like two columns and a beam that are all rigid) however my code does not work , I am using : integrator LoadControl 1 1 1 1 test EnergyIncr 1.0e-6 10 1 algorithm Newton numberer Plain constraints Transformation 1.0 system SparseGeneral analy...

As I said, I am using average acceleration method and based on chapter 5 of Chopra's book with this method we dont expect to have instability in the response regardless of time step length! So, I dont understand what is happening here.

Dear vesna, Thanks for your help. just another question, I decreased the mass in your example to model a massless system, this time if you check the acceleration data you see there is a stability problem, even with average acceleration method. Do you have any idea? Because I wanted to use this metho...

Do you have any suggestions?

Yes, It looks fine but the results I get with this code is wrong. I assumed the mass is negligible, so I found the displacement , velocity and acceleration by running a number of static analysis. And also, since the force function is harmonic , I expect to get cosine function for velocity and sine f...

Hi all; I wanted to impose a dynamic force on one of the nodes of my structure and do dynamic time history analysis. But the velocity and acceleration that I get seems wrong. To figure it out, I defined a simple example. force.txt is the text file of function : F=10*sin(2*pi*t) with dt=1/20. I assum...