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Frank, Lets say I want to assign an initial acceleration of 0.981 m/s2 to node 4. In acc.txt file there is 0.981 value as only 1 row without anything else. ==================== pattern MultipleSupport 100 { set accSeries "Series -dt 0.0005 -filePath acc.txt -factor 1.0"; groundMotion 500 P...

Explanation:

By spring coeficient "k", I mean the "E", modulus of elasticity of the "uniaxialmaterial elastic" .

uniaxialMaterial Elastic $matTag $E <$eta>

I called $E as "k" and $eta as "c" in the previous message.

I am working on site response analysis and I want to use elastic base with outcropping motion. When we define the seismic input in terms of shear stresses (or forces for 2D) we define a zero length element with dashpot and spring. We can calculate the damping coefficient (c) of dashpot by using the ...

When we download the code from CVS, there is another OpenSees directory in the main OpenSees directory. And I believe they are exactly the same. What is the use of it? Is it for updating purposes with CVS?

Thanks

Let me ask the question again. Im applying a dynamic force history to a node. Dynamic force history is a sine function and it is a function of velocity. As force history starts from zero ( velocity starts from 0), initial acceleration and displacement shouldnt be zero. How can I solve this problem? ...

Frank,

How can I remove it after 1step?

Thanks

When I use 1.0 for HHT (integrator HHT 1.0 ), I get the same result as Newmark Avg Acceleration (Newmark 0.5 0.25) . For HHT, gamma=1/2*(1-2*alpha) and Beta=1/4*(1-alpha)^2 So when alpha=0 then HHT should be the same as Newmark Avg Acc. Thus, actually in the command manual the provided information f...

Whats the difference between Newmark and HHT? When I use Newmark for my nonlinear soil domain analyses, Im getting high frequency responses, but in HHT high frequencies disappear. Which one should I trust ? Im using a very small time step like 1/800 sec for both Newmark and HHT. And secondly questio...

I am applying a dynamic load to nodes 3 and 4 as follows : set force1 "Series -dt 0.005 -filePath LOAD1.txt -factor 0.5"; pattern Plain 2 $force1 { load 3 1 0 load 4 1 0 } [b]I also want to add an initial acceleration to nodes 3 and 4. How is this possible? [/b] I guess this should be a bi...

How does OpenSees read the input files? Lets say I want to apply a dynamic force and the input file has a column like : 50 100 150 and the time step is 0.005 sec. Does OpenSees read the file as follows ? time Force 0 0 0.005 50 0.010 100 0.015 150 or like this? time Force 0 50 0.005 100 0.010 150 Th...

Whats the difference between using a quad element with fluidsolidporous material and using a fournodequadup element? We can get one pore pressure value (as for one element) by using quad element with fluidsolidporous material. For the fournodequadup element, we can get 4 pore pressure values at each...

I have a 1-D soil column (quad elements) with dashpots at the bottom as in Lysmer Boundary case. Lateral nodes are constrained in both directions. Im trying to find the reactions at the bottom and apply them to solve the static gravity analysis. However, Im confused with the material update stage. W...

Hi everyone, I am getting different results in the ""normal stresses "" with OpenSees versions 2.00 and 2.10 for the same input using USCD soil models. For example, if you run example 3 on the USCD website, cyclic.ucsd.edu/opensees/Plastic%20Pressure%20Independent%20Wet%20Level%2...

Thx Silvia, So, does that mean that we cant check whether the program reads our input file correctly or not? I mean, by using recorder command I am getting an output file. The program looks like it does everything correctly. I dont see any error and it creates the output file. But the results are wr...

Hi all, I want to know if it is possible to get a file which summarizes all the input that the program reads. I have been using OpenSees in Windows for a while and then I compiled it with Linux, but the results of two OS`s didnt match. I am trying to figure out why this could happen. Either somethin...