Dear Lammps users
I’m trying to model aluminum 7075 alloy under tensile loading in order to get the stresses and strains
I’m using the MEAM potential in the model, where I got the parameters for the parameter file from the literature
the model is running fine but the stress is dropping after the yield point where it shouldn’t
I have noticed something which I can’t understand, when the ialloy parameter in the parameter file has the value of 2, the model is running fine ,but if I change the number to 1 or 0 I get this error “LOST ATOMS”
I have no knowledge in the potential files and the meaning of the parameters
Can anyone please help and explain to me what is happening
Thanks and regards
Isra
the fact that a simulation is completing does not automatically mean that all its inputs are correct, only that they are not grossly wrong.
whether a simulation using published parameters is working correctly is best verified by reproducing results of the publication.
the format of the parameter files for MEAM is documented in the pair style documentation. the meaning of the parameters is discussed in the publication(s) of the MEAM potential (and variants), which are named in the documentation. changing parameters without knowing what they mean is a very bad idea.
the GI-GO rule applies.
axel.
Dear axel
Thank you for the fast reply
I’m actually trying to reproduce the results in a published paper but the parameters of the parameter file are not mentioned in that paper and I got them from a different paper
Unfortunately results are not matching after the yield point and I did follow exactly the model description in the paper
My question is could the parameters of the parameter file be different? In other words for the same alloy would their be two different parameter files?
I did read the published papers on MEAM potential but still couldn’t understand the meaning of all parameters
Regards
Isra
Dear axel
Thank you for the fast reply
I’m actually trying to reproduce the results in a published paper but the parameters of the parameter file are not mentioned in that paper
and I got them from a different paper
so you need to reproduce results from the other paper first to make certain you have transcribed the parameters and settings correctly.
and you need some way to make certain that the parameters you use and the same as in the paper you want to reproduce.
Unfortunately results are not matching after the yield point and I did follow exactly the model description in the paper
i have seen the phrase “I did follow exactly the model description in the paper” or something similar many times on this list and more often than not, it was not true. It is a good strategy to be very doubtful of being able to do something exactly as somebody else described it, especially when you are as inexperienced as you seem to be. one of the things that makes somebody more of an expert is the realization of how many (unexpected) ways there are to make a mistake.
My question is could the parameters of the parameter file be different?
that is a question for the authors of the paper you want to reproduce.
In other words for the same alloy would their be two different parameter files?
sure.
I did read the published papers on MEAM potential but still couldn’t understand the meaning of all parameters
then you need to study more to understand that. this is not something the mailing list can help you with.
axel.