ABAQUS - increase the size of the interior elements

Hello everyone,

I am currently working on modelling ITZ zones in concrete 2D microstructure. ITZ is the cement paste zone near the surface of aggregate which differs in properties from bulk cement paste. The thichness of ITZ zone ranges from 10-50 micrometer (0.01 - 0.05 mm). The size of RVE I am using is 100X100 mm which makes ITZ a very fine detail in my microstructure. I have created a instance in abaqus merging all parts, Aggregate, ITZ and Matrix( Cement Paste).

I seeded the instance with using these parameter:

Global Size: 2

Maximum deviation factor = 0.0001 (Approximate no of element per circle 7854)

Minimum size value = 0.1

these parameter ensures that I get same size elements at ITZ region regardless of size of perticular aggregate.

Now here is my problem:

This seeding gives me the meshing in Picture 1, in which element size decrease from outer boundary to ITZ zone, but not increases again after passing the ITZ zone and getting into Aggregate region. My required mesh can be seen in Picture 2. Can anyone help me with this?

In abaqus documentation, there is mention of "increase the size of the interior elements" but it says one can only do it when using tetrahedral element. Can I do it 2D case using quad dominated elements?

Thanks.

Vasav Dubey

Graduate Student

Texas A&M University