Can not get a correct acceleration when running the example of absorbing boundary2D.

[Thomas_CZX]

Dear STKO Team,

I download the absorbing boundary2D example from STKO E-learning website,

2dexample.rar

(126.32 KiB) Downloaded 202 times

but when I run this example the acceleration time history curve oscillates violently.

111.png (106.85 KiB) Viewed 3903 times

The correct response should be something like below:

112.jpg (31.5 KiB) Viewed 3903 times

This is strange because it is just a simple 2D model with elastic material and absorbing boundary2D. I have checked every parameters are the same as in the video, and the size of the elements are already very small. Can you give me some suggestion about how to fix this problem? Many thanks!

[STKO Team]

In the current OpenSees version, the TRBDF2 integrator does not work if the system is Linear with -factorOnce.
So you either uncheck the -factorOnce, or use Newmark or any other integrator

[Thomas_CZX]

It works correctly now , many thanks for your guide!

[STKO Team]

You're welcome