Hello, I have been tring to understand the concept of mechanical damping using in ADONIS and FLAC, however I am still confused about the time integration when it comes to displacement boundary conditions.
Say I have a plane strain 1x1 box being compressed oedometrically up to 10% axial strain.

newmodel()
rect("startPoint",0,0,"endPoint",1,1)
discretize("maxedge",0.1)
triangle("maxedge",0.1)
material("create","IsoElastic","matid",1,"matname","Material 1","density",2500,"shear",3759.4,"bulk",9803.92)
material("assign","matid",1)
applybc("xfix","xlim",0.993,1.023,"ylim",0.018,0.933)
applybc("xfix","xlim",-0.032,0.012,"ylim",0.050,0.927)
applybc("xfix","xlim",-0.306,1.031,"ylim",-0.024,0.018)
applybc("yfix","xlim",-0.175,1.047,"ylim",-0.028,0.014)
applybc("yvel",-0.1,"xlim",-0.046,1.037,"ylim",0.977,1.041)
hist("add","ydisp","atPoint",0.516,0.865)
solve()
plot("contour","ydisp")

If I have no control on the size of the time step, or the number of steps it takes to solve, how can I control the imposed displacement?

Thank you

Hi,

exact same problem has been explained in the post below please take a look:

http://geowizard.org/forum/index.php?topic=289.0

"fix" command in the program means fix the applied velocity to the nodes. If is everything is zero (first step), fixed node means no displacement but if you apply velocity you need to fix the same node to be able to apply constant velocity through cycling. for instance in your script after applybc("yvel".... you need to add this:
applybc("yfix","xlim",-0.046,1.037,"ylim",0.977,1.041)

time-step in the static mode is 1 (i.e. dt = 1) so if you want to apply 1m fixed displacement you need run model for 10 steps (0.1x10=1) to get to that displacement. I recommend you choose small displacement as boundary condition and increase the number of steps to avoid shocking the model with initially large displacement. for instance use:

applybc("yvel",-1.0e-5,"xlim",-0.046,1.037,"ylim",0.977,1.041)
...
...
solve("numstep",100000)

-Roozbeh

Thank you Roozbeh,

This is clear now. Another issue I am having is with the history plot. If I change the code to:

newmodel()
k=1000
rect("startPoint",0,0,"endPoint",1,1)
discretize("maxedge",0.1)
triangle("maxedge",0.1)
material("create","IsoElastic","matid",1,"matname","Material 1","density",2500,"shear",3759.4,"bulk",9803.92)
material("assign","matid",1)
applybc("xfix","xlim",0.993,1.023,"ylim",0.018,0.933)
applybc("xfix","xlim",-0.032,0.012,"ylim",0.050,0.927)
applybc("xfix","xlim",-0.306,1.031,"ylim",-0.024,0.018)
applybc("yfix","xlim",-0.175,1.047,"ylim",-0.028,0.014)
applybc("yvel",-0.1/k,"xlim",-0.046,1.037,"ylim",0.977,1.041)
applybc("yfix","xlim",-0.046,1.037,"ylim",0.977,1.041)
hist("add","ydisp","atPoint",0.5,1)
solve("numstep",k)
plot("chart","hist","id1",1)

I still get an empty history plot

your script is running fine and I see the history plot. please move the program folder to different drive (if it's in C:) and make sure no antivirus preventing ADONIS from writing in the folder. every-time you use history command program tries to create a file and store all the data in it. if it's prevented history won't show up. it's very rare but might be a possibility.

You were right, moving it to a non-system folder made ir run. Thank you

Actually, the problem seems to be repeating the operation. If I load the script for the first time, it shows the history plots, if I ask it to be loaded again these plots come back empty. I have to close the program, and load the script again.

But anyway, thank you for you help

thanks for your feedback, I'll take a look into this and try to recreate the issue and address it in the next release.