Compression Test to find Global Young's Modulus

[chillss]

First of all I'm quite new to Abaqus so I would like some help on my situation.

I have created a 2-D square with circles inside. Then I have fixed the bottom (encastre) and also applied a boundary condition to the top edge so it displaces 2% of the height of the square to act as compression.

The square and hence each individual element has been assigned a homogeneous material with an arbitrary young's modulus and poison's ratio. The point of this test is to see how the global young's modulus of the whole structure will differ from the arbitrary young's modulus due to the holes (acting as porosity which should weaken the structure).


However the problem is that I am not quite sure how to get the global young's modulus. I have tried to get the XY data for single nodes at the top edge and plot their Mises Stress vs Displacement (which then converted into strain). However when I try at different nodes, the young's modulus can be quite different (20-30%) and I'm not sure if my results are accurate.

Do you think there is a way where I can get the total stress values experienced by the entire top edge instead of just at each element? Or do you think there is another way of going about this?

You can see attachments for my file

 

[ESPcomposites]

I would not look at the stress, but rather the applied load. You might want to use the (total applied load)/area to be the effective stress in your calculation.

Since you applied an enforced displacement, you will need to find the corresponding load to reach that level. I don't know about CAE, but Patran has a free body tool for that. I am sure there is a way to do it in CAE though. The other option is to apply a load, rather than a displacement, though that could present a problem of nonuniform displacement(have not looked at the model).

Brian

http://www.espcomposites.com