you need to use UMAT subroutine to develop your progressive damage model. Hashin criterion does not take into account the stiffness degradation....

You have to include the temperature effect as well beside the stiffness degradation

Hajer Boussetta

Dear Hajer

thanks for ur comment. Hashin damage progressive damage model has the damage evolution ability which can simulate damage progression based on the fracture energies of fiber and matrix. Is that's right?

Mohamed M.A. Ammar

Hi Mohamed

thanks a lot

But i didn't understand why the temperature effect is needed and how can i include it.

I would happy to guide me further

Hi Mehdi,

The material deformation leads to temperature increase.

You can add it using the same subroutine.

Dear Mehdi:

I suggest U provide more detail about your numerical model, including the element types, the boundary conditions, the material properties etc.so that we can come up with suitable solutions.

HSNFT criterion is very low, so that indicate the failure is not caused by tension of fibers. First of all you have to check fiber direction coordinate system, because sometimes it is incorrectly defined by default. So check laminate direction and material coordinates. Secondly, check material properties defined in the model. ALso check shearing criterion. Regards

Thanks to all my friends ..

The composite ring was modeled as Shell (S4R) element and rigid constraint were applied to disks. Upper disk pulled up and bottom was fixed. also friction coefficient value of 0.1 was defined between disk and the specimen.

I work on the model with try and error and the force-displacement became better .. but still the force-displacement curve was not match to experimental tests ...

I don't know which parameters should be change in Abaqus model to improve results .. ????

Displacement in fracture in EXP. is about 4mm but in FEM is 0.9 mm ....

E1=45 GPa

E2=12.5 GPa

v12=0.28

G12=4.5 GPa

XT=1400 MPa

XC=650 MPa

YT=50 MPa

YC=140 MPa

S=65 MPa

Ft /Fc/ mt /mc 12.5 / 12.5 / 1/ 1 N/mm ; fracture energies for hashin damage model.

Mehdi,

Note that the differences in the force-displacement curves start as soon as loading is applied, which means that the initial stiffness is different (the initial slope is different). This usually indicates that either the elastic properties or the boundary conditIons (or both) are not set correctly. I suggest that you investigate this problem first (before drawing conclusions about the peak load)

Good luck!

Juan A Hurtado

thanks dear Juan ...

You are exactly right ....

I check those issues again.

Juan A Hurtado

Dear Juan ,

I have another challenge !!

I agree with u about initial material stiffness and strength but how B.Cs affect on the Force-Displacement response?

thanx