Yade

how does yade calculate the boundary displacement when I give a strain

Asked by dan.wang

I applied strain to the boundary to calculate the stress.
I used O.cell.velGrad to reach the goal strain(periodic boundary is used).
And my question is :
How does Yade calculate the boundary displacement using the strain I applied (dt, loadstep are known)?

I read part your Dr. 's paper and the source code(Cell.cpp) and still don't know. Can you please tell the theory or where can I find the paper that detailly talks about it?
Thanks!

Question information

Language:
English Edit question
Status:
Expired
For:
Yade Edit question
Assignee:
No assignee Edit question
Last query:
Last reply:
Revision history for this message
Bruno Chareyre (bruno-chareyre) said : 		#1

Hi,
There is no boundary hence no "boundary velocity".
The infinite periodic space is simply deformed at a certain rate as defined by the velocity gradient L=velGrad, so that a point at position x is shifted to x+L*x*dt after a small time increment.
I hope it helps.
Bruno

Revision history for this message
dan.wang (dan.wang) said : 		#2

so you mean each sphere will change its coordinate according to the shift formula x'=x+L*x*dt?

Not Just the coordinate of the period node?

Revision history for this message
dan.wang (dan.wang) said : 		#3

In your Dr's paper, page 29, section 2.6, "periodic boundary condition"
it tells that:

according to the reference size s, corners(0,0,0) and transformation T, which can be wrote as T+=T0+velGrad*dt*T0.

So how does the T work? From the source code in Cell.cpp, I can hardly know what does the variable "trsf" do next...

Thanks!

Revision history for this message
Launchpad Janitor (janitor) said : 		#4

This question was expired because it remained in the 'Open' state without activity for the last 15 days.