How to Apply Lateral Boundary Attachment for a 1D Model in FLAC2D 9.4?

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1

Hi everyone,

I am migrating a 1D dynamic analysis from FLAC 8.1 to FLAC2D 9.4 and I am having difficulty reproducing the lateral boundary attachment condition.

In my FLAC 8.1 model, the two lateral boundaries were attached to each other using:

attach aside from 1,1 to 1,_mj bside from 2,1 to 2,_mj

This was used to make the corresponding gridpoints of the two lateral boundaries have the same horizontal motion, which is required to reproduce 1D soil-column behavior.

For the dynamic stage, I also released the horizontal restriction using:

free x j 2 _mj

n FLAC2D 9.x, I understand that the attach command has been replaced/modified, but I am not sure what is the correct syntax to reproduce this specific condition between the two lateral boundaries of a 1D model.

What is the recommended FLAC2D 9.x code to attach the corresponding gridpoints of the two lateral boundaries in a 1D model, equivalent to the FLAC 8.1 command above?

I am specifically looking for the lateral attachment between the two sides, rather than using free-field boundaries.

Any example or guidance would be greatly appreciated. Thank you!

2

Hello Miguel_S

I am using following function to attach side boudary nodes :

fish define PeriodicBC(gPnt,gpGroup,gpSlot)
global M_xMin, M_xMax, _Attach_List
global ModelSize = M_xMax-M_xMin
if gp.isgroup(gPnt,gpGroup,gpSlot)
local pos1 = gp.pos(gPnt)
local pos2 = pos1 + vector(ModelSize,0)
local id1 = gp.id(gp.near(pos1))
local id2 = gp.id(gp.near(pos2))
command
zone attach gridpointid [id2] to-gridpointid [id1]
endcommand
endif
end

zone gridpoint group ‘bound=left’ range p-x [M_xMin] tol 1e-3
zone gridpoint group ‘bound=right’ range p-x [M_xMax] tol 1e-3
[PeriodicBC(::gp.list,‘left’,‘bound’)]

You can use this function by changing [M_xMin] and [M_xMax] model boundaries for both 1D and 2D analyses.