Hi Madhu,
On 01/08/2016 10:45 PM, Madhu Mahadevappa wrote:
Yes, you are right about the strain tensor.
First I will try to implement the material model. Could you give me some more information about the implementation of the material model, I mean some key starting points on how to do this?
You will need to write functions, that for current displacements computes the stress (and tangent modulus) - basically (25) and (26) in the document you sent. Those functions will be used in a new term you need to implement as well (check our developer's guide). You will need to somehow keep track of the various strain components - you can store data in an attribute of the term.
I am not sure how to use it without the time solver - sfepy does not use the incremental formulation anywhere, so this would also be a new thing (=up to you).
r.
Regards, Madhu
On Friday, 8 January 2016 11:08:45 UTC+1, Robert Cimrman wrote:
Hello Madhu,
On 01/07/2016 10:22 PM, Madhu Mahadevappa wrote:
Dear Robert,
I want to implement a constitutive model for ice in compressionwhich is developed using damage mechanics. Damage mechanics in the model utilizes Schapery's approach, which in turn derived from non-linear viscoelastic theory.I also want to implement an explicit solver which can capture high-speed dynamic events accurately.Could you help me understand what it will take to implement this material model, what SfePy can already do, and what I will need to contribute to for making this project work?
You will need to implement a new term, a more complex version of [1], that captures your constitutive equation. Am I right, that the small strain tensor is used, as in the term [2]?
Concerning the explicit time-stepping solver, there is a very basic version [3], but I do not think it will be of much use for you - you will be on your own here, as for the method(s). I can only support you with advice on how to add such a thing to sfepy. Having a good explicit solver would be a very nice addition.
[1] http://sfepy.org/doc-devel/developer_guide.html#how-to-implement-a-new-term [2]
http://sfepy.org/doc-devel/src/sfepy/terms/terms_elastic.html#sfepy.terms.te... [3]
http://sfepy.org/doc-devel/src/sfepy/solvers/ts_solvers.html?highlight=expli...
This project is being carried out to know how easy is to use SfePy for the research that is going on in our university and to contribute for open source softwares like SfePy. The results will also be validated by comparing with the experimental.
Thanks for your interest, contributions are welcome! Feel free to ask more.
Please refer the attached paper for further details about the material model.
Looking at the model implementation section, that should be doable (equations (23)-(29)). I guess the more difficult part will be the explicit solver.
r.