Hello:

I have a very unique problem here with Abaqus Standard!

I have a very slim fracture in which I am trying to simulate proppant transport, and the this very narrow fracture is embedded inside a plain strain porous elastic material.

As I am trying to solve this problem under a condition where my porous elastic material is in geostatic equilibrium at initial condition, i am noticing a couple of weird things:

1. No matter what, Abaqus always assumes that the initial gap of the fracture is 0.002 (that is the default value for Abaqus for an cohesive traction element), even I though I specifically say that the fracture width in my model is about ten times smaller (2.0e-4)!!! I have used the following:

*Initial Conditions, Type-Initial Gap

elset_name, 2.0e-4

(But Abaqus Standard does not get the message!!! When I see the simulation run, the parameter PFOPEN, the fracture width parameter, always shows up as 2.0e-3!!!!!)

I have also specified the thickness under *Cohesive section, but absolutely nothing!!!!

Another way is to specify the following keywords:

*Section Controls, Initial Gap Opening

elset_name,

But whenever I tried to insert these keywords anywhere, the job got aborted, and the specific solution to this was stated clearly!!!! Would you know where in my .inp file, can i write down these keywords?

2. There seems to be no variation at all, whatsoever, with the fracture width across the the entire fracture length!!! I expected the fracture to be wider at the injection node, where I am injecting fluids and proppants at a constant during step 2 and step 3, and narrower towards the other end!!! In other words, there would have been some variation in the fracture width across the x-axis, but there is none at all!!! Is there any geomechanical equilibrium issues causing this?

I have attached the .inp file.

Any input or thoughts on this would be greatly appreciated! Thank you very much!