A phase mixture model of a particle reinforced composite

[vinnuram]

Hey all,
I am Vinnu Arige.I am doing a project on A phase mixture model of a
particle reinforced composite.Here composite is treated as mixture of
viscoplastic metal matrix an reinforcing particle phase and a porous
elastoplastic boundary phase.As i considered the Strengthening
mechanisms and the constitutive modelling approach such as dislocation
density related constitutive equations are considered.Porosity is to
be considered in the boundary phase.

As i am pretty new to abaqus, i need some clarifications :
1.How should i consider the non dimensional dislocation density factor
in the equation in abaqus?
2.Does UMAT works for this case?
3.And also can porosity be considered in abaqus and how?
4.How should a sub routine written: i mean like which file(like note
pad or through fortran only)
5.If anybody have a sample subroutine for user defined material
subroutine, please let me know?

Or if anybody can suggest any other idea u are welcome.

This might look really small questions for all of you in groups but as
i am new to using abaqus its difficult for me.
Thank you and hope to see ur relpies

[Jorgen]

Hi Vinnu,

Sounds like an interesting and challenging project!

Here are a few comments:
1. Well, you need to either use an existing model or develop your own model for how the dislocation density influences the mechancal response.
2. Once you have a constitutive model that you like, you can then create an ABAQUS umat that implements the model.
3. Yes, you can incorporate porosity. One simple way is to consider the porosity to be a state variable. In your UMAT you can then keep track of how the porosity changes during the loading.
4. You can write a UMAT or VUMAT subroutine using any text editor. I personally like emacs.
5. I recommend that you carefully study the ABAQUS manuals. There is an example UMAT presented and discussed in the user manual.

Best of luck,
Jorgen