Dear Tejanath Reddy Sureddy

I am referring to version 2.0.3 and plasticity model "phenopowerlaw":

tau0_slip is the initial slip resistance, it determines the yield point. The more you increase tau0_slip, the higher the yield point. You can use this property to match the experimental yield point in the stress-strain curve.

tausat_slip is the slip resistance after all hardening has taken place (saturation). You don't need to keep the same ratio between tau0_slip and tausat_slip.

The second important parameter you should fit is the hardening rate, which is the increase of stress per unit plastic strain. That is determined by the parameter h0_slipslip.

Once you are done with tau0_slip and h0_slipslip, you can fine tune the other parameters, such as tausat_slip.

Trust this helps.

Best Regards,

Nicolò Grilli

Dear Tejanath Reddy Sureddy,

Thanks to Nicolo for the detailed information on tuning of parameters. I agree with all of them as I have used the tuning process for Ferrite phase before I simulated my steel having ferrite and cementite phases. One thing which I want to add is the modification of the fitting parameters which are 'n' and 'w' in my case (listed at the end of the phase parameters).

These parameters also have the over all effect on the global stress strain diagram of the material.

Dear Nicolo Grilli

Thanks for your valuable suggestions. This helped me a lot. Another query is how can I simulate using DAMASk if multi phases are present and do we have to change the parameters for all the phases or changing parameters of the highest volume fraction of the phases is sufficient?

Dear @Muhammed Umar

Thanks for your suggestions. Can you please elaborate about 'n' and 'w' parameters. What do they represent and what effects will they have on the simulations? Thanks in advance

Regards,

S TEJANATH Reddy

Dear Tejanath Reddy Sureddy

The multiphase material can be modelled by resolving the two different phases,

meaning you can assign different materials properties to different regions of the sample. This can be done in DAMASK as explained here:

https://damask.mpie.de/bin/view/Usage/Abaqus

You will need to create two different materials with different constants.

The first constant (homogenization scheme) will be the same,

the second constant (microstructure) will be different to model the two phases.

For instance you will have in the input file:

*User Material, constants=2

1.,1.

*User Material, constants=2

1.,2.

for the two different phases. Then, in the material.config file you will have in the microstructure block:

[Phase1]

crystallite 1

(constituent) phase 1 texture 1 fraction 1.0

[Phase2]

crystallite 1

(constituent) phase 2 texture 2 fraction 1.0

Then two different constitutive models in the block and different orientations in the block.

If you don't need to resolve different phases, you can use the homogenization schemes available, for instance RGC. These allows you to include different phases that are homogenized for each element, so no need to define different materials in different regions. However, you lose the spatial resolution.

The details are described in the recent publication:

Article DAMASK – The Düsseldorf Advanced Material Simulation Kit for...

and in the thesis by Prof. Franz Roters:

https://pure.mpg.de/rest/items/item_2014632_1/component/file_2014631/content

Best Regards,

Nicolò Grilli

i am new also, i want to ask how to paint tensile stress-strain curve from the data (.txt) each increment ?

DAMASK is about to be released in version 3. There is already a substantial amount of the reworking documented on the website https://damask3.mpie.de. Please check out some of the examples that demonstrate how to directly plot stress–strain curves from the HDF5 result file (small adaptation of https://damask3.mpie.de/documentation/examples/plot_per_grain_scatter.html).

Philip Eisenlohr

The new webpage looks amazing.

Nicolò

Hi, do you know how to draw the pole figure and inverse pole figure from the result calculated by damask3.0 (i.e. HDF5 file)